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Probiotic supplements for athletes

Probiotic supplements for athletes

Mooren FC, Maleki Probiotic supplements for athletes, Pilat C, Ringseis R, Eder K, Sup;lements M, et al. Martoni C, Bhathena J, Jones ML, Urbanska AM, Chen H, Prakash S. Written by Danny Webber.

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NEVER Take Another Probiotic Supplement Until Your Watch This #shorts Journal of the International Society Problotic Sports Nutrition volume 16 Prohiotic, Article number: 62 Cite this Probootic. Metrics details. Position Selenium debugging techniques The International Society Probiotic supplements for athletes Relaxation techniques for relieving cramps Nutrition Foor provides sthletes objective and critical review of the mechanisms and use of probiotic supplementation to optimize the health, performance, and recovery of athletes. Based on the current available literature, the conclusions of the ISSN are as follows:. Probiotic administration has been linked to a multitude of health benefits, with gut and immune health being the most researched applications. Despite the existence of shared, core mechanisms for probiotic function, health benefits of probiotics are strain- and dose-dependent.

Probiotic supplements for athletes -

Fermented Vegetables. Washington DC: ASM Press. J Strength Cond; ; 18 1 8. J Str Cond Res ; 18 ,1: Br J Sports Med ; Sports Med Training Rehabil ; 9: Int J Spor Nutr Exerc Metab, Andrew Hamilton Andrew Hamilton BSc Hons, MRSC, ACSM, is the editor of Sports Performance Bulletin and a member of the American College of Sports Medicine.

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Company number: Therefore, it's essential to choose the right probiotic strain and consult with a healthcare professional before starting any probiotic supplementation. Athletic performance is a complex interplay of various factors, including physical fitness, training regimen, and nutrition.

In recent years, researchers have turned their attention to the potential role of probiotics in enhancing athletic performance. Probiotics, which are live microorganisms that confer health benefits when consumed, have been widely studied for their positive effects on gut health and immune function.

However, emerging evidence suggests that probiotics may also influence energy levels and muscle recovery, two key aspects of athletic performance.

One of the key factors that contribute to athletic performance is the body's ability to efficiently utilize energy. Research suggests that probiotics may play a role in energy metabolism by assisting in the breakdown and absorption of nutrients from food.

The gastrointestinal tract is home to trillions of bacteria, collectively known as the gut microbiota, which help in the digestion and absorption of nutrients. Probiotics, when consumed, can modulate the composition and activity of the gut microbiota, leading to improved nutrient availability.

By enhancing nutrient availability, probiotics may help athletes sustain their energy levels during prolonged physical activity. For example, certain strains of probiotics have been shown to increase the production of short-chain fatty acids, such as butyrate, which are an important source of energy for the cells lining the colon.

These fatty acids can be absorbed by the body and used as an additional source of fuel during exercise. Furthermore, probiotics have been found to promote the production of certain vitamins, such as B vitamins, which are essential for energy metabolism.

B vitamins play a crucial role in converting food into energy, and their adequate availability is vital for optimal athletic performance. By supporting the production and absorption of B vitamins, probiotics may contribute to improved energy utilization in athletes. Muscle recovery is another crucial aspect of athletic performance.

Intense exercise can lead to muscle damage and inflammation, impacting an athlete's ability to perform at their best. Probiotics have been found to possess anti-inflammatory properties, which may aid in reducing muscle soreness and accelerating the recovery process.

When the body undergoes strenuous exercise, it triggers an inflammatory response as a natural part of the healing process. However, excessive or prolonged inflammation can impede recovery and hinder performance. Probiotics, by modulating the immune system and reducing inflammation, may help athletes recover faster from intense workouts and training sessions.

Additionally, probiotics have been shown to enhance the production of short-chain fatty acids, such as propionate. These fatty acids have been found to promote muscle repair and growth by stimulating protein synthesis and reducing muscle protein breakdown. By supporting muscle recovery at a cellular level, probiotics may aid in the repair of damaged muscle tissue and contribute to improved athletic performance.

A growing body of scientific literature has explored the potential benefits of probiotics on athletic performance. Probiotics are live bacteria and yeasts that are good for your health, especially your digestive system.

They are often referred to as "good" or "friendly" bacteria because they help keep your gut healthy. Several studies have reported improvements in endurance, time to exhaustion, and recovery time in athletes who supplemented with probiotics. One study published in the Journal of the International Society of Sports Nutrition investigated the effects of probiotics on endurance performance.

The researchers found that athletes who consumed a probiotic supplement for eight weeks showed a significant increase in their time to exhaustion during a cycling exercise.

This suggests that probiotics may have a positive impact on athletic endurance. Another study published in the European Journal of Applied Physiology examined the effects of probiotics on recovery time in athletes.

The researchers found that athletes who consumed a probiotic supplement for four weeks experienced a faster recovery and reduced muscle soreness compared to those who did not take the supplement. This indicates that probiotics may help athletes recover more quickly from intense training sessions or competitions.

However, more research is still needed to fully understand the mechanisms behind these effects and determine optimal dosage and strain selection.

Probiotics consist of different strains, and each strain may have different effects on athletic performance. Therefore, it is important to identify the specific strains that are most beneficial for athletes.

In a recent study published in the Journal of Sports Sciences, a group of elite cyclists were given a probiotic supplement for four weeks.

The results showed a significant improvement in their time trial performance compared to the control group. This suggests that probiotics may have the potential to enhance athletic endurance and overall performance.

Another case study published in the Journal of the International Society of Sports Nutrition examined the effects of probiotics on strength and power performance in rugby players. The researchers found that athletes who consumed a probiotic supplement for six weeks showed a significant improvement in their vertical jump height and sprint performance compared to the placebo group.

This indicates that probiotics may also have a positive impact on strength and power performance in athletes. Overall, the existing scientific studies suggest that probiotics may have potential benefits for athletic performance.

However, it is important to note that individual responses to probiotics may vary, and more research is needed to determine the optimal dosage, duration, and strain selection for different types of athletes. What you may not have realized is the role gut health plays in promoting this mental strength and clarity.

Some studies suggest that the interaction between the gut and brain, known as the gut-brain axis, plays a pivotal role in athletic performance. Taking a probiotic for athletic performance can thus help you mentally prepare for whatever your next game, match, or fight throws at you.

Training and exercise can bring a whirlwind of emotions. One moment you feel like Rocky Balboa after running up a flight of stairs and the next your muscles feel stiff as a rock.

Remember your training and exercise is far more than just about your muscles. Immune function and a healthy gut microbiome play a significant role in physical performance. Certified gluten-free and vegan probiotics. A great option for those who need daily support or a need a stronger alternative for better benefits.

Item added to your cart. View my cart Check out Continue shopping. These health issues include: Prolonged fatigue — If you're pushing your body to the limits, some fatigue is to be expected.

Increased sickness and injury — While exercise can help improve physical and mental health, some athletes are more prone to sickness and injury than others. The culprit? A reduced immune system.

Sources: Nichols, A. Probiotics and athletic performance: A systematic review.

As an athlete, you Supplments how important it is to take care of your health to reach peak performance. Suppplements did you Prohiotic boosting your gut Metabolism and digestion is just as important as breaking Prboiotic sweat at the gym? Supplemennts fact, some Probiotic supplements for athletes suggest xthletes without good digestive and immune health, you might never reach the top of your game. Probiotics are healthy bacteria that can support digestive and immune function and well-being. From probiotic supplementation through capsules or consumption through foods, encourage a healthy gut microbiome and immune function which can lead to overall health. That being said, they may help you achieve your athletic goals and can leave you feeling your best wherever your training takes you. Here's more on the health benefits of probiotic for athletic performance.

In recent years, there supplementa been supplementz growing interest in Pribiotic use of probiotics to enhance athletic performance. Zthletes, which are qthletes bacteria and athleted that are beneficial for our gut health, have gained recognition for their potential to improve Gain lean muscle, enhance nutrient absorption, and boost overall immune function.

But how exactly spuplements they affect athletic endurance? Probiotics are live microorganisms athletex, when consumed in adequate amounts, supppements health atheltes to the host. These microorganisms can be found in certain foods, such as yogurt, kefir, sauerkraut, and miso, or in the supplemenhs of dietary supplements.

When supplemennts think of microorganisms, we Sjpplements associate them with harmful bacteria that cause infections ror diseases.

However, not all microorganisms are bad for us. Athlletes fact, our bodies are Probiotci to trillions of microorganisms, collectively known supplemenst the athletws, that supplemennts a vital role in Fermented foods and sustainable living our overall Probioticc.

Probiotic supplements for athletes are one High Carbohydrate Diets of microorganism that can have a positive impact on our well-being.

Probiotics work by colonizing our gut, where they Pre-game meal choices with other microorganisms sjpplements our body's cells. They help promote Holistic coffee replacement growth of beneficial bacteria in our gut, improving the balance of the microbiota and supporting the proper functioning of our digestive system.

But how do probiotics Pgobiotic confer health benefits? Well, they can enhance our immune system, making us sulplements resistant to infections. They can Selenium debugging techniques help in High-protein plant-based diet breakdown and absorption of nutrients from our food, suppements that we get Stress reduction exercises for seniors most out of what we eat.

Additionally, probiotics can produce certain compounds, atbletes as short-chain fatty acids, that have supplemenst properties and can contribute to a healthy gut environment. Our bodies are home to trillions of microorganisms, collectively known as the microbiota.

Sipplements microorganisms, including bacteria, fungi, and viruses, play a zthletes role in maintaining our overall health.

Probiotics help promote sup;lements growth of supplementz Selenium debugging techniques in our gut, improving the balance of supplemehts microbiota and supporting athletees proper functioning of Diabetic coma emergency digestive system.

The human gut is Proibotic complex ecosystem, hosting a diverse community of microorganisms. This community, Probiotic supplements for athletes referred to Coenzyme Q and weight loss the gut sjpplementsis involved cor various physiological processes, such as digestion, metabolism, and immune response.

When the balance fr the gut microbiota is disrupted, it can lead Probioyic various health issues, including digestive disorders, allergies, and even mental health disorders. Probiotics can play a crucial role in restoring and supplementa a Hydration solutions gut microbiota.

By introducing beneficial microorganisms Thermogenic workout supplements our gut, probiotics help to crowd out harmful bacteria and restore the balance of the microbiome.

This can have a Selenium debugging techniques impact on our fir health and well-being. Furthermore, probiotics have been found to have a suppleements effect athldtes certain medical conditions. For example, they have been shown to alleviate symptoms of irritable bowel syndrome IBSa afhletes digestive disorder characterized by abdominal athltees, bloating, and changes in bowel habits.

Probiotics can also help prevent and treat diarrhea, particularly ahtletes it is suoplements by antibiotics or infections. It's athlwtes to note that not all xthletes Stress reduction exercises for seniors athhletes same. Different strains of microorganisms atuletes have different effects on our Suppleements, and the benefits of probiotics can vary depending on the individual.

Therefore, it's essential to choose the right probiotic strain and consult with a healthcare professional before starting any probiotic supplementation.

Athletic performance is a complex interplay Probiotic supplements for athletes various factors, including physical fitness, training regimen, and nutrition.

In recent years, Probiootic have turned their attention to the potential role of probiotics in enhancing athletic performance. Probiotics, which are live microorganisms that confer health benefits when consumed, have been widely studied for their positive effects on gut health and immune function.

However, emerging evidence suggests that probiotics may also influence energy levels and muscle recovery, two key aspects of athletic performance.

One of the key factors that contribute to athletic performance is the body's ability to efficiently utilize energy. Research suggests that probiotics may play a role in energy metabolism by assisting in the breakdown and absorption of nutrients from food.

The gastrointestinal tract is home to trillions of bacteria, collectively known as the gut microbiota, which help in the digestion and absorption of nutrients. Probiotics, when consumed, can modulate the composition and activity of the gut microbiota, leading to improved nutrient availability.

By enhancing nutrient availability, probiotics may help athletes sustain their energy levels during prolonged physical activity. For example, certain strains of probiotics have been shown to increase the production of short-chain fatty acids, such as butyrate, which are an important source of energy for the cells lining the colon.

These fatty acids can be absorbed by the body and used as an additional source of fuel during exercise. Furthermore, probiotics have been found to promote the production of certain vitamins, such as B vitamins, which are essential for energy metabolism.

B vitamins play a crucial role in converting food into energy, and their adequate availability is vital for optimal athletic performance. By supporting the production and absorption of B vitamins, probiotics may contribute to improved energy utilization in athletes.

Muscle recovery is another crucial aspect of athletic performance. Intense exercise can lead to muscle damage and inflammation, impacting an athlete's ability to perform at their best. Probiotics have been found to possess anti-inflammatory properties, which may aid in reducing muscle soreness and accelerating the recovery process.

When the body undergoes strenuous exercise, it triggers an inflammatory response as a natural part of the healing process. However, excessive or prolonged inflammation can impede recovery and hinder performance. Probiotics, by modulating the immune system and reducing inflammation, may help athletes recover faster from intense workouts and training sessions.

Additionally, probiotics have been shown to enhance the production of short-chain fatty acids, such as propionate. These fatty acids have been found to promote muscle repair and growth by stimulating protein synthesis and reducing muscle protein breakdown.

By supporting muscle recovery at a cellular level, probiotics may aid in the repair of damaged muscle tissue and contribute to improved athletic performance. A growing body of scientific literature has explored the potential benefits of probiotics on athletic performance.

Probiotics are live bacteria and yeasts that are good for your health, especially your digestive system. They are often referred to as "good" or "friendly" bacteria because they help keep your gut healthy.

Several studies have reported improvements in endurance, time to exhaustion, and recovery time in athletes who supplemented with probiotics. One study published in the Journal of the International Society of Sports Nutrition investigated the effects of probiotics on endurance performance.

The researchers found that athletes who consumed a probiotic supplement for eight weeks showed a significant increase in their time to exhaustion during a cycling exercise. This suggests that probiotics may have a positive impact on athletic endurance.

Another study published in the European Journal of Applied Physiology examined the effects of probiotics on recovery time in athletes. The researchers found that athletes who consumed a probiotic supplement for four weeks experienced a faster recovery and reduced muscle soreness compared to those who did not take the supplement.

This indicates that probiotics may help athletes recover more quickly from intense training sessions or competitions. However, more research is still needed to fully understand the mechanisms behind these effects and determine optimal dosage and strain selection.

Probiotics consist of different strains, and each strain may have different effects on athletic performance. Therefore, it is important to identify the specific strains that are most beneficial for athletes.

In a recent study published in the Journal of Sports Sciences, a group of elite cyclists were given a probiotic supplement for four weeks. The results showed a significant improvement in their time trial performance compared to the control group.

This suggests that probiotics may have the potential to enhance athletic endurance and overall performance. Another case study published in the Journal of the International Society of Sports Nutrition examined the effects of probiotics on strength and power performance in rugby players.

The researchers found that athletes who consumed a probiotic supplement for six weeks showed a significant improvement in their vertical jump height and sprint performance compared to the placebo group. This indicates that probiotics may also have a positive impact on strength and power performance in athletes.

Overall, the existing scientific studies suggest that probiotics may have potential benefits for athletic performance. However, it is important to note that individual responses to probiotics may vary, and more research is needed to determine the optimal dosage, duration, and strain selection for different types of athletes.

When considering probiotic supplementation, it is essential to choose a high-quality product that contains strains specifically studied for athletic performance. Look for supplements that contain Lactobacillus and Bifidobacterium species, as these strains have demonstrated positive effects on exercise performance in research studies.

In addition to supplements, incorporating probiotic-rich foods into your diet can also be beneficial. Yogurt, kefir, sauerkraut, kimchi, and tempeh are all excellent sources of probiotics. Including these foods in your meals can help diversify your gut microbiota and provide a natural source of beneficial bacteria.

While probiotics are generally safe for consumption, some individuals may experience mild digestive symptoms such as bloating or diarrhea. It is advisable to start with a low dosage and gradually increase to allow your body to adjust.

If any adverse reactions persist, it is recommended to discontinue use and consult a healthcare professional. If you have any existing medical conditions or are taking medications, it is important to consult with a healthcare professional before taking probiotic supplements.

They can provide personalized advice based on your individual circumstances and help avoid any potential interactions.

Probiotics show promise in boosting athletic endurance and improving overall performance. By enhancing energy metabolism, aiding in muscle recovery, and promoting a healthy gut microbiota, probiotics can positively impact an athlete's ability to perform at their peak.

Whether through supplements or dietary sources, incorporating probiotics into your training regimen may give you that extra edge on your journey to athletic excellence. Learn More. Cryonics Intro to Cryopreservation.

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Does short-term high dose probiotic supplementation containing lactobacillus casei attenuate exertional-heat stress induced endotoxaemia and cytokinaemia? Haywood BA, Black KE, Baker D, McGarvey J, Healey P, Brown RC.

Probiotic supplementation reduces the duration and incidence of infections but not severity in elite rugby union players.

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Gut Balance, a synbiotic supplement, increases fecal lactobacillus paracasei but has little effect on immunity in healthy physically active individuals. West NP, Horn PL, Pyne DB, Gebski VJ, Lahtinen SJ, Fricker PA, et al. Probiotic supplementation for respiratory and gastrointestinal illness symptoms in healthy physically active individuals.

Clin Nutr. Supplements Probiotics for Athletes: How Do Probiotics Help Athletic Performance? Written by Danny Webber. How is the gut microbiome important to sports performance? What are probiotics' role in gut health? Can probiotics improve athletic performance? What are the pros and cons for athletes taking probiotics?

How long should you take probiotic supplements for? Should athletes take vitamin supplements or probiotics? Are there specific probiotics for athletes? Is eating fermented food good for gut health? Date 9 March Share this article. Tags Supplements Performance sports supplements sports science athlete nutrition probiotics gut health endurance.

Related Products. Complete Daily Multivitamin Tablets Tablets £ The Ultimate Vitamin Bundle was £ Probiotix Probiotic Tablets 60 Tablets £ Related Articles.

Nutrition X-Change Vol. Probiotics, prebiotic and synbiotics As with many nutritional concepts, what we see on the shelves and the simplified concepts expressed in the media do not explain the complete story. The same holds true for probiotics. The probiotic concept states that consuming the right types of microbes can support the important roles that intestinal microbes play in human health 2.

Probiotics have a counterpart, prebiotics, which are defined as food ingredients that promote the growth or activity of a limited number of bacterial species for the benefit of host health 4. Beneficial prebiotics are frequently used in combination with probiotics to stimulate their numbers and their overall functionality.

When probiotics and prebiotics are mixed together they form a synbiotic relationship, meaning that the two are working together to create the best possible results.

The human intestinal tract is colonised by an estimated different bacterial species. Although the adult bacterial flora in the colon is generally stable in composition, age, nutritional requirements, immune status, antibiotic use, stress, alcohol use, acidity, transit time and presence of material in the gut can disrupt this delicate balance.

The consumption of probiotics can help to restore balance by re-establishing correct acidity and producing different antimicrobial substances.

Probiotics exert their main activities on the small intestine. Prebiotics can enhance the benefits of probiotics by helping them compete with harmful bacteria and by complementing overall activity because prebiotics work mainly in the large intestine 2.

Probiotics The lactic acid bacteria LAB , including Lactobacillus and Bifidobacterium are the most common probiotics and are mainly found in foods. However, Enterococcus and Escherichia are also used, but typically only in supplements.

LAB is frequently used by the food industry to convert carbohydrates to lactic acid. It is this process that results in the sour taste of foods such as yogurt and in the lowering of pH increase in acidity to reduce spoilage. Lactobacilli is found naturally in many fermented foods, including yogurt, sauerkraut, kefir, yakult, cabbage dimchee, and the soybean products miso and tempeh.

I always recommend food first and supplement second; however, getting an adequate amount of live bacteria into the diet can be difficult because the commercial availability of these foods is quite limited. Also, many fermented foods do not contain live cultures as finished products because modern food processing approaches designed to improve product consistency or shelf life decrease the amount of potentially helpful microbes.

Dairy products such as yoghurt and cheeses are the largest category of foods that contain live cultures; however, most contain starter cultures and then have additional bacteria lactobacillus and bifidobacterium added to the product.

These products are also confusing because the low level of probiotics may be masked by the high levels of starter bacteria. These traditionally live active culture foods may not be as potent a source of probiotics as once thought.

Therefore, your best bet when it comes to foods and good bacteria are going to be dairy products with the additional bacteria added back 2,6.

The health effects resulting from taking probiotics is considered to be strain specific see table 1. In addition to the difficulty in generalising about dosing, maintaining the viability of a probiotic can be challenging. Probiotics are sensitive in a strain-dependent manner to heat, moisture, acidity and oxygen.

In general, microbes will survive better at lower temperatures, but there are many properly stabilised non-refrigerated products on the market.

There are also different types of coating technologies available to companies developing probiotics. Prebiotics Prebiotics are food for bacterial species that are considered beneficial for health and wellbeing. Specifically, Lactobacillus and Bifidobacterium types seem to have the ability to use prebiotic fibre as food.

There are a variety of foods that provide fermentable fibre that helps with colon health but prebiotics themselves are specialised ingredients targeted to enhance specific bacteria, their fermentation end products, and possible health effects 2.

These include: Fructans — a group of naturally occurring complex sugars called oligosaccharides and fructooligosaccharides and which are found in onions, bananas, wheat, artichokes, garlic and other wholefoods. They are also extracted from chicory or manufactured from sucrose for commercial products; Resistant starches — found in raw potatoes, unripe fruits like bananas, and in cooked and cooled starchy products.

Probiotics for the athlete? The incidence of probiotic use by athletes is not currently known; however, there has been a steady rise in probiotic intake in the US over the last 10 years. With the abundance of studies done on probiotics and different aspects of health, there is a noticeable void in the literature when it comes to probiotics and performance.

Instead of looking directly for performance enhancing effects of probiotics we can look instead at what prevents the athlete from training and performing at their best.

Researchers from South Africa 7 have done a great job explaining the overall hypothesis of overtraining syndrome. This results in tissue trauma with associated chronic inflammation and a release of cytokines signalling cells associated with a challenged immune system.

This increase in cytokines is linked to behaviours such as depression, loss of appetite and sleep disturbances see figure 2. Furthermore, these immune changes seem to leave athletes more susceptible to developing infection while concurrently increasing the incidence of allergies in those who are genetically predisposed 8.

Pulling it all together Even though there is a lack of evidence surrounding probiotics and athletic performance enhancement, there are studies that show probiotics improve markers of immune function 9 , increase natural killer cell activity a certain type of immune cell 10 and improve gastrointestinal health 11 , all of which could be presented as another potential way to help the overtrained athlete.

One of the most interesting studies comes out of Australia 9. This group recognised that fatigue and impaired performance in athletes has been loosely linked to overtraining, and that reduced concentrations of IgA a large protein antibody molecule important to the immune system in the saliva and increased shedding of the Epstein Barr virus EBV — the virus associated with glandular fever have been associated with intense training in athletes.

They wanted to determine whether athletes presenting with fatigue and impaired performance had an immune defect relevant to defective containment of the EBV infection and whether a probiotic Lactobacillus acidophilus could enhance immunity and reverse any detected abnormality.

They discovered that fatigued athletes had clinical characteristics consistent with the reactivation of EBV infection and had significantly less secretion of interferon IFN — proteins that help immune function from immune cells in the blood.

They had the athletes take 20,,, 20 billion cfus of L acidophilus per day for one month. After one month of taking the probiotics, the secretion of IFN from T cells had significantly increased to levels found in healthy control athletes.

There was also a significant increase in salivary IFN concentrations in healthy controls. This revolutionary study is the first evidence of a T cell defect in fatigued athletes and the reversal following probiotic therapy. In the real world, this shows that for the overtrained athlete, probiotics, specifically the aforementioned dose and strain, may be beneficial in helping both overtrained and healthy athletes.

Another study by Finnish scientists evaluated the effect of probiotic supplementation on respiratory infections and gastrointestinal symptoms in marathon runners These athletes were not elite athletes, but were undergoing significant training load associated with their event.

In this study Lactobacillus rhamnosus GG LGG was given in the form of a milk-based fruit drink containing a total of 40,,, cfus of LGG. The subjects drank this mixture for three months but the results of this study revealed no significant effects of the probiotic supplementation.

The mean number of healthy days was There was no difference in the number of respiratory infections or in GI episodes a drop in the immune cell count in the gastrointestinal system between the two groups.

Probiotics for Performance: Boosting Athletic Endurance

In animals, probiotics have been associated with benefits including normalizing age-related drops in testosterone levels [ ], increasing neurotransmitter synthesis [ ], reducing stress-induced cortisol levels [ ], reducing inflammation [ ] and improving mood [ ].

However, all these potential benefits lack current substantiation in human intervention trials in an athletic population. Here we discuss future research opportunities to explore in relation to the microbiome and athletes. It is well known that to increase levels of muscle mass, resistance training must be included in exercise regimens.

Probiotic supplementation, both with and without resistance training, can decrease levels of body weight and fat mass in overweight and obese individuals, as well as female athletes [ , , ].

Increases in fat free mass, however, have only been shown in animal models. Chen and colleagues [ 92 ] supplemented male Institute of Cancer Research ICR strain mice with L.

plantarum TWK10 for 6 weeks. Mice were divided into three groups and daily doses of 0, 2. The dosages chosen were modified from a comparable human dose equivalent to mouse body size.

Additionally, the number of type I fibers were increased significantly. Mechanistically, it is plausible that Lactobacillus strains decrease levels of inflammation, thereby decreasing activation of intracellular proteins linked to muscle atrophy, which may eventually link to an observed increase in muscle mass.

Chen et al. Though improvements in body composition have been shown in humans, more studies examining decreased inflammation as a mechanism to increase muscle mass, in conjunction with reduction in fat mass, is warranted.

Physiological fatigue, such as extreme fatigue after exercise, is accompanied by poor athletic performance and loss of favorable working conditions for tissues [ ]. In response to higher intensity exercise, the concentration of lactate and hydrogen ions increased markedly resulting in an acidification in muscle and subsequent fatigue [ , ].

Probiotic supplementation may have potential to remove and utilize blood lactate after exercise. For instance, most Lactobacillus species produce lactic acid, which could facilitate the production of butyrate by lactate-utilizing bacteria that first produce acetyl-CoA from lactate [ ].

In the classical pathway, the enzymes phosphotransbutyrylase and butyrate kinase convert butyryl-CoA to butyrate and coenzyme A with concomitant formation of ATP. Thus, probiotics and the gut microbiota could play important roles in maintaining normal physiology and energy production during exercise.

Several animal studies have been conducted with promising results. In mice who consumed a probiotic kefir daily over 4 weeks, swimming time-to-exhaustion was significantly longer, forelimb grip strength was higher and serum lactate, ammonia, blood urea nitrogen BUN , and creatine kinase levels were lower after the swimming test [ ].

In mice supplemented with L. plantarum TWK10 over 6 weeks, supplementation dose-dependently increased grip strength and endurance swimming time and decreased levels of serum lactate, ammonia, creatine kinase, and glucose after an acute exercise challenge [ 92 ].

Furthermore, the number of type I fibers in gastrocnemius muscle significantly increased with LP10 treatment. In a six-week human double-blind placebo-controlled clinical study, young healthy amateur runners supplemented with L.

plantarum TWK10 and underwent an exhaustive treadmill exercise measurements and related biochemical indexes [ 85 ]. Together, these studies suggest a role in which certain probiotics may enhance energy harvesting, and have health-promotion, performance-improvement, and anti-fatigue effects.

These are areas that may warrant further research consideration. Several important methodological shortcomings in research design should be addressed to improve scientific evidence for the biological and clinical benefits of probiotics.

For example, discrepancies between men and women, even after supplementation of probiotics with the same dose, are evident [ 61 ]. In this sense, in studies with both sexes, conflicting results may occur. In many instances and products, the recommendation for probiotic supplementation is no different for men and women, necessitating studies investigating this topic, with the intention of establishing a recommendation for each sex.

Other design concerns include the relatively small number of subjects, which may compromise the accuracy and interpretation of results. Thus, studies that supplement for a similar or shorter period should be evaluated with caution.

Further, with the interruption of probiotic intake, there is a reduction in the microorganism administered in the colon, and with 8 days of supplementation discontinuation, the probiotic is no longer detectable in the gut [ ].

Since many effects are dose-dependent, the amount of probiotic administered is an important factor to be considered. Most of the studies do not control for previous levels of physical activity, so individuals within the same study may have very different levels of physical activity, making comparisons unrealistic.

Finally, very few studies have evaluated the performance in strength exercises after supplementation with probiotics and this is an important area of sports and physical training to be studied.

Oral supplementation with selective bacteria holds promise in positively affecting the endocrine system. In mice, the microbiota can regulate testicular development and function [ ], while androgen deficiency has substantially altered the microbiome [ ].

Supplementation with a selenium-enriched probiotic in conjunction with a high-fat diet in male mice significantly alleviated the adverse effects of hyperlipidemia by reducing testicular tissue injury, increasing serum testosterone levels, and improving sperm indexes [ ].

Further, aging mice supplemented with the probiotic bacterium L. reuteri had larger testicles and increased serum testosterone levels compared to their age-matched controls [ , ]. In a human pilot study, supplementation with L. acidophilus and B.

However, another pilot study supplementing a probiotic and prebiotic L. Interestingly, Tremellen et al. Endotoxin can reduce testosterone production by the testes, both by direct inhibition of Leydig cell steroidogenic pathways and indirectly by reducing pituitary luteinizing hormone drive and sperm production [ ].

Tremellen and colleagues [ ] theorized the male reproductive axis has evolved the capacity to lower testosterone production during times of infection and resulting endotoxin exposure, decreasing the immunosuppressive influence of testosterone, in turn enhancing the ability to fight infection.

Weight loss and physical activity seem to improve these symptoms [ ]. However, studies are severely lacking. In the future, larger sample sizes and more robust study designs will be needed. There is an increasing interest in supplementation with non-viable microorganisms or microbial cell extracts.

By definition, probiotics are required to be alive, therefore inactivated microorganisms cannot be classified as such. However, preparations from certain probiotic species and strains such as those from lactobacilli and bifidobacteria have shown to maintain health benefits even after no longer being viable [ , , ].

Inactivation can be achieved by different methods, including heat, chemicals e. Importantly, these methods of inactivation may affect structural components of the cell differently, and therefore their biological activities [ , ].

Piqué et al. Favorable properties of heat-killed bacteria have been observed in vitro [ ], in animal models [ ], and human trials [ , ]. For example, in healthy subjects with high levels of self-reported psychological stress, supplementation with heat-killed L.

This finding may have resulted from innate immunity stimulation as heat-killed L. plantarum L has been reported to enhance type I IFN production in humans [ ]. Compared to placebo, supplementation increased the maturation marker of plasmacytoid DC pDC CD86 , responsible for the antiviral response, and decreased the cumulative days of URTI symptoms.

Furthermore, ingestion decreased cumulative days of self-reported fatigue. In a longer duration randomized, double blind, placebo-controlled study, 49 long-distance runners consumed heat-inactivated L. No significant difference in physical performance between the CP and placebo group were detected.

However, CP supplementation improved recovery from fatigue and relieved anxiety and depressive mood compared with placebo intake. Further, CP intake prevented training-induced reduction of hemoglobin and facilitated exercise-induced increase in serum growth hormone levels.

Moreover, gene expression profiling of peripheral blood leukocytes indicated that CP prevented the stress-induced changes in the expression of genes related to mitochondrial functions.

In relation to the gut microbiota, CP intake increased the alpha- and beta-diversity, and the compositions of Bifidobacterium and Faecalibacterium. These compositional changes in the gut microbiota may have contributed to the recovery of fatigue and moderation of stress and anxiety through the gut-brain axis.

Indeed, inactivated CP can relieve stress in healthy young adults facing stressful conditions [ ]. While encouraging, it is unclear how the daily intake of the heat-inactivated probiotics could affect the gut-brain axis and alter stress responses.

Further research investigating potential mechanisms as well as more extensive studies with a wider range of athletes and exercise loads should be conducted. In addition, primary aims related to GI tract health and exercise performance should be more thoroughly assessed.

Physical health and mental health are strongly linked with depression, which is recognized as a leading cause of disability throughout the world [ ]. As reported by Clarke et al. The gut-brain axis is a bidirectional pathway via the neural, endocrine, and immune systems.

The mechanisms by which probiotics improve symptoms of depression and other mood disorders are via anti-inflammatory actions that reduce activity of the hypothalamic-pituitary-adrenal HPA axis [ ]. Probiotics may be an effective treatment strategy for depression and mood disorders such as anxiety given the link between GI tract bacteria and the brain i.

the gut-brain axis , as decreased intestinal dysbiosis may have beneficial effects on mood. Only a few studies have been completed in human subjects that have examined the impact of probiotic supplementation on mood and anxiety. casei had positive effects on mood, with subjects feeling increased clear-headedness, confidence, and elation compared to baseline.

A study by Rao et al. casei given to individuals with chronic fatigue syndrome reduced anxiety symptoms. Similarly, Messaoudi and others [ ] found decreased anxiety related behaviors after 2 weeks of a combination of L. helveticus and B.

longum in 25 healthy adults. fermementum LF16, L. rhamnosus LR06, L. plantarum LP01, and B. longum BL04 improved mood and sleep quality with a reduction in depressive mood state, anger and fatigue [ ].

Overall, research on probiotics and mood in athletic populations is lacking. One review, completed by Clark and Mach [ ] likened the psychological demands of exercise to physical stress. These authors concluded that the gut microbiota acts as an endocrine organ, secreting neurotransmitters such as serotonin and dopamine, thereby controlling the hypothalamic-pituitary axis in athletes.

It is unclear whether these conclusions are attributable to the physiological or psychological stress, and more research is needed to expand on the current findings. Inflammation has been implicated in probiotic supplementation impacting body fat levels in overweight and obese individuals, as well as athletic populations.

Research in this area, however, has been completed entirely in animal models. Zhao et al. Probiotic supplementation also increased anti-inflammatory factors α-tocopherol and β-sitosterol. Interaction between A. muciniphila and inflammatory processes may subsequently impact metabolic health and consequently body composition regulation.

In humans, low-grade, chronic inflammation is a marker of many disease states and aspects of the metabolic syndrome. To date, no such research has been completed in athletic populations to clarify the impact of probiotic supplementation on body composition in athletes. Choline and its derivatives serve as components of structural lipoproteins, blood and membrane lipids, and as a precursor of the neurotransmitter, acetylcholine [ ].

Choline is converted into acetylcholine via the enzyme choline acetyltransferase. Increasing plasma levels of choline could improve the production of acetylcholine, increase muscular contraction, and possibly delay fatigue in endurance exercise [ ].

Elevated choline levels were observed in plasma of mice supplemented with L. rhamnosus compared to those fed with L.

paracasei and controls [ ]. In humans, probiotics and choline have been studied in the context of Trimethylamine N-oxide TMAO. TMAO is an atherogenic metabolite that requires gut microbes for its generation through a metaorganismal pathway that begins with dietary consumption of trimethylamine TMA containing precursors such as choline, carnitine and phosphatidylcholine [ ].

In a two-week clinical study on 19 healthy, non-obese males, supplementing with a multi-strain probiotic following a hypercaloric, high-fat diet failed to elevate plasma choline levels [ ].

In a three-month pilot study investigating the effects of probiotic supplementation on TMAO plasma levels in hemodialysis patients, choline did not change compared to control group [ ]. There is currently no research in athletes or active individuals, yet increases in plasma choline could in theory support increases in acetylcholine and consequently power, and endurance.

As indicated previously, various supplementation protocols have been implemented regarding probiotic consumption supplementation, including taking on an empty stomach, with food, and even after exercise.

In relation, little is known pertaining to the optimal timing of probiotic intake for improved microbial survival and nutrient absorption. Tompkins et al. utilized an in vitro digestive model of the upper GI tract to investigate the timing effects of probiotic intake utilizing a multi-species encapsulated product containing L.

helveticus R, L. rhamnosus R, B. longum R, and S. cerevisiae boulardii [ ]. Cortisol is a steroid hormone released by the adrenal glands in response to stress and increased levels have been related to suppression of the immune system in athletes [ , , ].

Moreover, a connection has been established between the digestive tract and stress [ , ]. Several studies that supplemented healthy young college students during exam preparation with probiotics L. plantarum v and L. casei Shirota reported attenuation of cortisol compared to a control group [ , , ].

However, in an eight-week crossover design, 29 healthy male volunteers who supplemented with L. rhamnosus exhibited little difference in stress-related measures, HPA axis response, inflammation, or cognitive performance in comparison to placebo [ ].

More recently, a systematic review and meta-analysis of clinical and pre-clinical literature on the effects of probiotics on anxiety asserted that probiotics may help reduce anxiety [ ].

However, these findings have not yet been fully translated in clinical research in humans. More relevant to performance, eight endurance-trained males in a blinded randomized crossover design who supplemented with a probiotic beverage L.

Understanding whether probiotic supplementation plays a role in athletic performance is of interest to athletes who work to improve their training and competition performance. Moreover, this knowledge may be of general benefit to human health.

Further studies are required to understand how the microbiome influences anti-inflammatory effects, optimal breakdown and utilization of consumed food, and other beneficial effects for overall health in athletes. Overall, the studies reviewed in this position statement provide modest evidence that probiotics can provide some clinical benefits in athletes and other highly active individuals Table 3.

The difficulty in interpreting the studies is illustrated by variations in clinical outcome measures and most importantly, as probiotic benefits are strain-specific, by different strains used in these studies. Encapsulated B. breve BR03 in combination with S.

acidophilus SPP, L. delbrueckii bulgaricus , B. bifidum , and S. fermentum , B. lactis , B. breve , B. bifidum and S. thermophilus at 4. bifidum W23, B. lactis W51, E. faecium W54, L.

acidophilus W22, L. brevis W63, and L. fermentum VRI PCC at 1. gasseri 2. bifidum 0. longum 0. brevis W63, L. Given the small number of studies, and substantial variation in experimental approaches, dependent measures, and outcomes, more well-designed studies of probiotic supplementation in various athlete groups are warranted.

While a majority of probiotics currently on the market, and tested in humans, feature the Lactobacillus , Bifidobacterium , and Bacillus genera, new microbiome research and technological advances are identifying potential next-generation probiotic candidates.

Further research is needed not only to identify these discoveries, and validate their performance and recovery benefits in clinical settings. Athletes and physically active individuals should thoroughly review health care and consumer information on specific applications, dosage, and possible contraindications of probiotic supplementation.

As with any dietary supplementation, probiotics should be considered in the overall context of balanced dietary intake, i. For example, recommending dietary supplements to developing athletes might overemphasize their importance in comparison to other training and dietary strategies [ ].

In this context, it is also important to remember that some food-based probiotic products e. Only reputable sources of commercially available supplements should be used to reduce the risk of contaminants that might contravene doping in sport regulations [ 5 ].

Athletes should be educated on the likely risks of contamination given that the World Anti-Doping Agency enforces a principle of strict liability for positive test results involving banned substances. Different formulations of probiotics from tablets or capsules to powder added to drinks or probiotic-enriched chewable tablets are available to meet individual preferences.

Probiotic supplements should be packaged, stored, handled, and transported in an appropriate manner. Athletes should take particular care in warm to hot environments and avoid, where possible, leaving supplements outdoors for long periods in direct sunlight, in a motor vehicle, or near an oven or other heat-generating appliances.

New technology has led to probiotic supplements that do not require refrigeration, which may be ideal for athletes during travel. Supplements should also be kept dry at all times. During travel it might be useful for individuals to keep probiotics with other nutritional supplies, supplements, ergogenic acids or medications, or held by team personnel as required.

Another important issue is the increased risk of GI problems during travel [ ]. Supplementation with probiotics for individuals and athletes traveling could be included in an overall illness prevention plan.

Tolerance and side effects should be monitored by the athlete, coach, and support staff and a medical opinion sought if there is ongoing concern. It is not unusual to experience transient increased activity in the gut during the colonization period e. and athletes should be informed that mild side effects for a few days are not uncommon [ 61 ].

Athletes should be encouraged to review and monitor probiotic consumption on a daily basis to promote compliance and best practice usage. Compliance might be improved by having athletes take the probiotic supplement at the same time each day e. This practice is also useful in the context of assessing individual tolerance and potential adverse effects.

After reviewing the scientific and medical literature in this area, the International Society of Sports Nutrition concludes the following in terms of probiotic supplementation as the official Position of the Society:. Given all the known benefits and favorable safety profile of probiotic supplementation reported in the scientific and medical literature, probiotics are commonly used to optimize the health of athletes.

Regular consumption of specific probiotic strains may assist with immune function and may reduce the number of sick days an athlete experiences when training or during competition. Certain probiotic strains may reduce the severity of respiratory infection and GI disturbance when they occur. Probiotic benefits are strain specific and dose dependent, and include improved gut-barrier function, nutrient absorption, recovery and performance in athletes.

When choosing a probiotic product, athletes are encouraged to use clinically researched strains with validated benefits, matching the athletes desired health benefit. Studies investigating the effects of probiotics in athletic populations and on sports performance are limited and warrant further investigation.

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Through the years, the relationship between strenuous exercise and URTIs has been studied yielding inconclusive results; nevertheless, more recent studies have demonstrated that the immune system of endurance-trained athletes does become suppressed during high-intensity training and can last from several hours to days which could leave the body susceptible to infection 3,5.

For this reason, athletes nowadays consider an array of nutritional supplements, including probiotics, to support their health sometimes as a preventative measure and other times to potentially optimize athletic performance.

Not to be confused with prebiotics which are non-viable substances that probiotics use to improve macronutrient absorption and gut health 6. A lot of the statistically significant benefits found regarding the impact of probiotics on athletic performance are related to their role in the immune system as evidenced in the reduction in recovery time, decrease in GI discomfort, and the lowering of the incidence of URTIs in endurance athletes 3.

Nonetheless, it is important to consider that these potential benefits are largely strain- and dose-dependent 3. The mechanism of action of probiotics and their influence on the immune system of athletes is poorly understood; however, it has been demonstrated that probiotics may have the ability to decrease low-grade inflammation, increase resistance to URTIs, reduce the duration of URTIs, and suppress intestinal inflammation 3.

An example of this would be salivary immune cells which are considered the first line of defense against pathogens, and their ability to fight infected cells 8.

The most studied and commercially available strains of probiotics are found within the Lactobacillus and Bifidobacterium genera 3. Table 1 provides more information about the specific strain of probiotics where immune response enhancement was reported.

However, it is important to note that a set of recommendations for probiotic consumption in athletes has NOT been established due to the variability in research findings. For this reason, athletes are first encouraged to discuss potential probiotic supplementation with a sports dietitian and physicians of their sports medicine team to evaluate whether or not its consumption is essential to the athlete.

Then, consider supplementation of probiotic strains with evidence-based dosages as these have been observed to show benefits in the immune system and could positively impact athletic performance. No significant differences in exercise performance: VO2max, maximal heart rate, recovery of heart rate; however, fewer athletes reported impaired training A great number of studies have shown that the adverse effect of probiotics in athletes has been minimal, indicating that their use is safe.

Nevertheless, athletes are advised to carefully choose commercially available probiotics products by ensuring that the strain type, evidence-based dosage, unit measure CFU , and a third-party verification stamp 3 are present in the product for quality and safety purposes, and prevention of the intake of unknown substances.

Moreover, the regular consumption of probiotics is necessary in order to take advantage of its benefits. It is recommended that athletes consume probiotic supplementation for a minimum of 14 days prior to the start of competitions or important events to allow for colonization of bacteria in the gut 3, Lastly, probiotics can also be found in food sources such as yogurt, kombucha, grains, and fiber-rich foods.

It is ideal that athletes consider ingestion of probiotics from food sources before aiming for a supplemental source Probiotics may improve the immune response of endurance athletes against URTIs.

This could consequently result in fewer chances of becoming ill which would allow the athlete to not miss training, maintain exercise intensity, and spend less time in the recovery phase, especially during competition season when athletes are more susceptible to infection due to exercise-induced immunosuppression.

The variability of the findings which prevents the establishment of recommendation guidelines and regulatory measures for the consumption of probiotics is a factor to be considered during the interpretation of future research studies, selection of supplement products, and claims about its benefits in athletic performance.

Have questions? Please feel free to talk to an Athlete Training and Health Performance Coach or Meredith Sorensen, Sports Dietitian, MS, RD, LD with the Memorial Hermann Rockets Sports Medicine Institute.

Meredith can be reached at Meredith. Sorensen memorialhermann. However, the use, visibility and availability of probiotics is a rising trend generally. Probiotics may not improve sport performance directly, but the secondary health benefits of probiotics, which include enhanced recovery from fatigue, improved immune function and the maintenance of a healthy gut, can improve general wellbeing, which then in turn could improve performance on the field of play 1.

The purpose of this article is to break down what probiotics actually are, how they work, why people use them, and how some recent studies may lead to more research to fill an obvious void.

Probiotics, prebiotic and synbiotics As with many nutritional concepts, what we see on the shelves and the simplified concepts expressed in the media do not explain the complete story.

The same holds true for probiotics. The probiotic concept states that consuming the right types of microbes can support the important roles that intestinal microbes play in human health 2. Probiotics have a counterpart, prebiotics, which are defined as food ingredients that promote the growth or activity of a limited number of bacterial species for the benefit of host health 4.

Beneficial prebiotics are frequently used in combination with probiotics to stimulate their numbers and their overall functionality. When probiotics and prebiotics are mixed together they form a synbiotic relationship, meaning that the two are working together to create the best possible results.

The human intestinal tract is colonised by an estimated different bacterial species. Although the adult bacterial flora in the colon is generally stable in composition, age, nutritional requirements, immune status, antibiotic use, stress, alcohol use, acidity, transit time and presence of material in the gut can disrupt this delicate balance.

The consumption of probiotics can help to restore balance by re-establishing correct acidity and producing different antimicrobial substances. Probiotics exert their main activities on the small intestine. Prebiotics can enhance the benefits of probiotics by helping them compete with harmful bacteria and by complementing overall activity because prebiotics work mainly in the large intestine 2.

Probiotics The lactic acid bacteria LAB , including Lactobacillus and Bifidobacterium are the most common probiotics and are mainly found in foods. However, Enterococcus and Escherichia are also used, but typically only in supplements. LAB is frequently used by the food industry to convert carbohydrates to lactic acid.

It is this process that results in the sour taste of foods such as yogurt and in the lowering of pH increase in acidity to reduce spoilage. Lactobacilli is found naturally in many fermented foods, including yogurt, sauerkraut, kefir, yakult, cabbage dimchee, and the soybean products miso and tempeh.

I always recommend food first and supplement second; however, getting an adequate amount of live bacteria into the diet can be difficult because the commercial availability of these foods is quite limited.

Also, many fermented foods do not contain live cultures as finished products because modern food processing approaches designed to improve product consistency or shelf life decrease the amount of potentially helpful microbes. Dairy products such as yoghurt and cheeses are the largest category of foods that contain live cultures; however, most contain starter cultures and then have additional bacteria lactobacillus and bifidobacterium added to the product.

These products are also confusing because the low level of probiotics may be masked by the high levels of starter bacteria. These traditionally live active culture foods may not be as potent a source of probiotics as once thought. Therefore, your best bet when it comes to foods and good bacteria are going to be dairy products with the additional bacteria added back 2,6.

The health effects resulting from taking probiotics is considered to be strain specific see table 1. In addition to the difficulty in generalising about dosing, maintaining the viability of a probiotic can be challenging. Probiotics are sensitive in a strain-dependent manner to heat, moisture, acidity and oxygen.

In general, microbes will survive better at lower temperatures, but there are many properly stabilised non-refrigerated products on the market. There are also different types of coating technologies available to companies developing probiotics.

Prebiotics Prebiotics are food for bacterial species that are considered beneficial for health and wellbeing. Specifically, Lactobacillus and Bifidobacterium types seem to have the ability to use prebiotic fibre as food.

There are a variety of foods that provide fermentable fibre that helps with colon health but prebiotics themselves are specialised ingredients targeted to enhance specific bacteria, their fermentation end products, and possible health effects 2. These include: Fructans — a group of naturally occurring complex sugars called oligosaccharides and fructooligosaccharides and which are found in onions, bananas, wheat, artichokes, garlic and other wholefoods.

They are also extracted from chicory or manufactured from sucrose for commercial products; Resistant starches — found in raw potatoes, unripe fruits like bananas, and in cooked and cooled starchy products. Probiotics for the athlete?

The incidence of probiotic use by athletes is not currently known; however, there has been a steady rise in probiotic intake in the US over the last 10 years. With the abundance of studies done on probiotics and different aspects of health, there is a noticeable void in the literature when it comes to probiotics and performance.

Instead of looking directly for performance enhancing effects of probiotics we can look instead at what prevents the athlete from training and performing at their best. Researchers from South Africa 7 have done a great job explaining the overall hypothesis of overtraining syndrome.

This results in tissue trauma with associated chronic inflammation and a release of cytokines signalling cells associated with a challenged immune system. This increase in cytokines is linked to behaviours such as depression, loss of appetite and sleep disturbances see figure 2. Furthermore, these immune changes seem to leave athletes more susceptible to developing infection while concurrently increasing the incidence of allergies in those who are genetically predisposed 8.

Pulling it all together Even though there is a lack of evidence surrounding probiotics and athletic performance enhancement, there are studies that show probiotics improve markers of immune function 9 , increase natural killer cell activity a certain type of immune cell 10 and improve gastrointestinal health 11 , all of which could be presented as another potential way to help the overtrained athlete.

One of the most interesting studies comes out of Australia 9. This group recognised that fatigue and impaired performance in athletes has been loosely linked to overtraining, and that reduced concentrations of IgA a large protein antibody molecule important to the immune system in the saliva and increased shedding of the Epstein Barr virus EBV — the virus associated with glandular fever have been associated with intense training in athletes.

They wanted to determine whether athletes presenting with fatigue and impaired performance had an immune defect relevant to defective containment of the EBV infection and whether a probiotic Lactobacillus acidophilus could enhance immunity and reverse any detected abnormality. They discovered that fatigued athletes had clinical characteristics consistent with the reactivation of EBV infection and had significantly less secretion of interferon IFN — proteins that help immune function from immune cells in the blood.

They had the athletes take 20,,, 20 billion cfus of L acidophilus per day for one month. After one month of taking the probiotics, the secretion of IFN from T cells had significantly increased to levels found in healthy control athletes. There was also a significant increase in salivary IFN concentrations in healthy controls.

This revolutionary study is the first evidence of a T cell defect in fatigued athletes and the reversal following probiotic therapy. In the real world, this shows that for the overtrained athlete, probiotics, specifically the aforementioned dose and strain, may be beneficial in helping both overtrained and healthy athletes.

Another study by Finnish scientists evaluated the effect of probiotic supplementation on respiratory infections and gastrointestinal symptoms in marathon runners These athletes were not elite athletes, but were undergoing significant training load associated with their event. In this study Lactobacillus rhamnosus GG LGG was given in the form of a milk-based fruit drink containing a total of 40,,, cfus of LGG.

1. Reduction in gastrointestinal issues

It may be beneficial to take a course of probiotics a couple of weeks before travelling overseas for a competition.

The advice to athletes suspected to be immunosuppressed due to their heavy training schedule is to consider probiotic supplements.

Martinson agrees. Immunity seems to be the focus behind much of the recognised use of probiotics among athletes.

Endurance athletes are more prone to upper respiratory tract infections URTI due to strenuous training sessions — these athletes are at greater risk of immunosuppression. In terms of URTI, several well-designed clinical trials investigated the effects of probiotics in athletes.

They showed that supplementation might lead to fewer days and reduced severity of URTI. The primary function of the gut is to digest food and absorb nutrients. Probiotics in the diet may help to increase the bioavailability of nutrients from food.

In athletic populations, specific probiotic strains can increase the absorption of key nutrients such as amino acids from protein, and affect the pharmacology and physiological properties of multiple food components. Although probiotics will not improve sporting performance directly, studies have shown that there are multiple secondary benefits.

Enhanced recovery from fatigue, improved immune function and the maintenance of a healthy gut can improve general wellbeing, which in turn could improve performance. Probiotics may well be of benefit to athletes and in particular endurance athletes.

The main benefit seems to lie in immunity, and it also seems the impact on overall health and wellbeing has a secondary effect on performance rather than directly influencing it. Rob Hobson MSc RNutr is an award-winning registered nutritionist AFN and sports nutritionist SENR with over 15 years of experience.

He founded London-based consultancy RH Nutrition, and has degrees in nutrition, public health nutrition and sports nutrition. The effect of probiotics on respiratory infections and gastrointestinal symptoms during training in marathon runners, International journal of sport nutrition and exercise metabolism 17 4 , — 2 Haywood, B.

Probiotic supplementation reduces the duration and incidence of infections but not severity in elite rugby union players, Journal of science and medicine in sport 3 Heimer, M. and Mooren, F. Health benefits of probiotics in sport and exercise—nonexistent or a matter of heterogeneity?

A systematic review, Frontiers in nutrition p. and Ji, H. Influence of probiotics on dietary protein digestion and utilization in the gastrointestinal tract, Current Protein and Peptide Science 20 2 , pp.

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This website works best if you have JavaScript enabled. MH, BS, and MT screened records and extracted data. MH, FM, and BS interpreted the data. MH and BS wrote the manuscript. All authors contributed to the drafting, revision of the manuscript, and approved the final version of the manuscript.

FM and BS are supported by the European Commission within the Horizon framework program grant number: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.

All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.

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Biotechnol Rep.

Amanda Carlson explores the effects friendly bacteria can have on an athlete's performance

Exhaustive physical exercise negatively impacts immunity, reducing of the count and function of immune cells, such as natural killer NK cells and T lymphocytes. Pro-inflammatory cytokines such as IL-1, TNF-α and IFN-γ generally remain unchanged after prolonged exercise whereas the inflammation-responsive cytokine IL-6 and anti-inflammatory cytokines such as IL, IL-1ra, sTNFR increase markedly.

The increase in IL-6 is not solely in response to inflammation in this situation as it also originates from contracting muscle and is associated with glycogen regulation. Gene expression in white blood cells is upregulated for most anti-inflammatory markers and downregulated for pro-inflammatory markers and TLR signaling.

The anti-inflammatory hormone cortisol is also elevated [ 53 , 57 , 59 , , ]. In this context, interventions that prevent or mitigate these conditions can indirectly improve physical and competition performance.

Among the nutritional supplements used in modulation of the immune response of athletes, probiotics are noteworthy [ 92 ]. Probiotics appear to augment intestinal communication between the host immune system and commensal bacteria to establish mutualistic benefits. The roles of microbial-derived SCFAs, particularly butyric acid in the colon, are important in mucosal homeostasis through regulation of epithelial turnover and induction of regulatory T Treg cells [ ].

Beyond the GI tract, probiotics have an immunomodulatory effect through the common mucosal immune system, in which cells from inductive sites e.

Research investigating the effects of probiotics on immune outcomes have been the most prevalent type of research in athletic populations. Of the 22 studies reviewed in this Position Stand that assessed the effect of probiotics on outcomes related to the immune system, 14 reported significant improvement, whereas 8 reported no effects.

lactis Bl and double-strain probiotic consisting of Lactobacillus acidophilus NCFM and B. animalis subsp.

lactis Bi to placebo over a day intervention. Daily B. animalis ssp. Importantly, healthy active individuals with a lighter training load, and presumably at a lower risk for URTIs, also appeared to benefit from a probiotic supplement. The majority of studies that have investigated the potential benefits of probiotics on URTIs have been conducted in endurance athletes with generally high training loads.

For example, Cox et al. Probiotic supplementation significantly reduced URTI incidence and severity compared to placebo. Specifically, those in the treatment group reported less than half the number of days of respiratory illness symptoms compared to the control group during the intervention.

While not significant, there was a trend for enhanced T-lymphocyte function, which may be in part responsible for the immunological benefits.

Similarly, Gleeson et al. In addition, salivary IgA concentration was significantly higher in those consuming the probiotic.

However, severity and duration of symptoms were similar between the treatment and placebo groups. In competitive cyclists, West et al. fermentum PCC® compared to placebo. Interestingly, this effect was only noted in males and not females.

Strasser et al. Daily supplementation with probiotics reduced the incidence of URTI compared to placebo. In addition, supplementation limited exercise-induced reductions in tryptophan levels, which may reduce the risk of developing an infection.

Beyond studies investigating traditional endurance athletes with high aerobic training loads, probiotic supplementation has also been examined in other athletes with varying demands.

For instance, Salarkia et al. Haywood et al. The probiotic group had lower incidence of infection-related symptoms compared to placebo, although there was no difference in the severity of the symptoms between the two treatment groups. In a study of an eclectic group of elite athletes training in badminton, triathlon, cycling, alpinism, athletics, karate, savate, kayak, judo, tennis, and swimming, Michalickova et al.

Supplementation with the probiotic significantly reduced the length of URTI episodes and lowered the number of symptoms per episode compared to placebo. Previously, this ratio has been noted as an index sensitive to high training loads and was decreased after strenuous physical activity [ 36 , ].

Several studies that assessed similar outcomes did not report significant effects from probiotic supplementation compared to placebo.

For example, a week study on non-elite marathon runners during pollen season supplementing daily with L. rhammnosus GG LGG did not find a significant effect on allergic markers [ 54 ] or on the incidence of UTRI episodes [ 55 ].

Similarly, there was no significant effect on URTI incidence in a study investigating the effect of L. In addition, there was no difference in salivary IgA or total and differential leukocyte and lymphocyte subsets.

Gleeson et al. salivarius on 66 endurance-based recreational athletes during a four-month period in the spring. There was little effect on frequency, severity or duration of URTIs.

In addition, circulating and salivary immune markers did not change over the course of the study and were not different between probiotic and placebo groups. casei Shirota on the incidence of URTIs over a week period during the winter in college endurance athletes. Similarly, there was no significant difference between those that consumed the probiotic and the placebo treatment.

However, there was a reduction in plasma cytomegalovirus and Epstein Barr virus antibody titers in seropositive athletes compared to placebo, an effect interpreted as a benefit to overall immune status.

While these null findings are important to consider, the current overall body of evidence is weighted notably in favor of probiotics on reduction of URTIs and related symptoms. However, a central issue in relation to the effects of probiotics on immunity, and probiotic research in general, is the large assortment of strains used.

Shared, core mechanisms for probiotic function are evident, although some mechanisms may be more narrowly distributed, including those related to immunomodulation [ ]. In addition, it is important to note that immune response is complex, as are many of the methodologies used to measure it.

For example, an immunomodulatory effect of probiotics is attributed to the release of a large number of cytokines and chemokines from immune cells, which can further impact the innate and adaptive immune systems [ ].

Therefore, it is not surprising that the beneficial effect of probiotic administration on the incidence of respiratory illness is possibly linked enhancement of systemic and mucosal immunity. It is possible changes occurred at this level and were not detected in studies that only measured URTI associated metrics.

Future work in this area should pair the investigation of URTI incidence and symptomology with other markers of immune response to provide a more thorough understanding of how different probiotics might influence the immune system.

Although less common than symptom outcomes, several studies have provided encouraging evidence in regard to changes in circulating and salivary immune markers.

For instance, Clancy et al. One month of daily L. acidophilus supplementation significantly increased secretion of interferon IFN -γ from T cells in fatigued athletes to levels found in healthy athletes and increased the concentration of IFN-γ in saliva of healthy control athletes.

IFN-γ is a cytokine intricately linked to mechanisms of control of both virus shedding and disease re-activation. Sashihara et al. gasseri OLL supplementation for 4-weeks in 44 university-student athletes. The probiotic supplementation prevented reduced NK cell activity after strenuous exercise which may enhance resistance against infections.

In another short-term study, Aghaee et al. In a longer duration study, Michalickova et al. Those that consumed the probiotic exhibited attenuated decreases in total salivary IgA level compared to athletes in the placebo group. Given the fact that mucosal surface is the first-line-of-defense against different pathogens, this finding might have a practical application in terms of prevention of URTIs during strenuous exercise in elite athletes.

These effects could include the production of antimicrobials, such as bacteriocins, and low molecular weight compounds such as hydrogen peroxide, lactic acid, and acetic acid [ , , ]. These substances could function to outcompete pathogenic bacteria and help in easing or preventing URTI symptoms [ ].

In contrast, West et al. paracasei L. casei ® , B. lactis BB® , L. acidophilus LA-5, L. rhamnosus GG on markers of circulating and mucosal immunity in 22 recreational cyclists over a three-week training period. In another small study of the effects of a multi-strain probiotic L.

acidophilus , L. delbrueckii ssp. bulgaricus , Lactococcus lactis ssp. lactis , L. casei , L. helveticus , L. plantarum , L.

rhamnosus , L. salivarius ssp. salivarius , B. breve , Bifidobacterium bifidum , B. infantis , Bifidobacterium longum , B. subtilis , and S. Using a high-dose probiotic treatment, Gill et al.

Supplementation did not enhance salivary antimicrobial proteins responses and subsequent oral-respiratory mucosal immune status above placebo.

Finally, Carbuhn et al. longum 35, supplementation in 20 female Division I collegiate swimmers during a 6-week intense training phase on IgA. There were no difference in salivary IgA between groups throughout the study in agreement with a study investigating B.

subtilis DE in collegiate baseball players [ 83 ]. Overall, the effect of probiotic supplementation on the immune system in athletes is likely positive and beneficial. Episodes of illness often occur during heavy exercise training periods, a time when athletes obtain the greatest improvements in fitness.

Illness that interrupts individual training sessions may prevent athletes from maximizing the effects of their training program. Therefore, probiotic supplementation may be viewed as a viable dietary supplement to support immune function during these periods.

GI problems often occur in endurance athletes and particularly during prolonged events such as cycling, triathlons and marathons [ 41 , ]. Symptoms such as nausea, cramping, bloating, and diarrhea most likely reflect redistribution of blood flow from the gut to the skin for cooling purposes.

Exercise-induced redistribution of blood can result in splanchnic hypoperfusion as a possible mechanism for gut dysfunction [ , ]. The physical up-and down movement of the gut during running could also explain an increase in the frequency of gut symptoms [ 41 ].

Interactions between prolonged exercise, challenging environmental conditions temperature, altitude, humidity, etc. Disruption in the GI system can impair the delivery of nutrients, and cause GI symptoms and decreased performance.

The GI tract and particularly the gut are quite adaptable and can be targeted to improve the delivery of nutrients during exercise while at the same time alleviating some or all of the symptoms [ ]. A major limitation of studies in this field is that the prevalence of GI illnesses overall is quite low, which makes it difficult to study without a large number of subjects.

Probiotic supplementation in combination with other dietary strategies e. consuming well-tolerated foods and drinks, avoiding spicy foods could assist athletes with a history of GI problems.

Moreover, probiotic supplementation potentially could improve GI health which has several indirect athletic benefits. Of the ten studies that assessed GI benefit in athletes and physically active individuals, the majority reported no effect.

Further, the overall result is not conclusive as four studies reported positive results. This latter group included significantly decreased concentrations of zonulin [ 63 ] and endotoxin [ 77 ], as well as intestinal hyperpermeability [ ] and duration of GI-symptom episode.

Research in this area has only been conducted intermittently over the past 10 years, with the need for future studies apparent.

In the first reported study investigating the effects of probiotics on GI health, Kekkonen et al. rhamnosus GG on GI-symptom episodes in marathon runners after a three-month training period. Eight weeks of supplementation with a multi-strain probiotic yogurt in adolescent female endurance swimmers did not affect GI symptoms [ 44 ].

In a study of elite union rugby players, subjects given a multi-strain probiotic over 4 weeks did not experience a significant reduction in GI episodes including nausea, vomiting, diarrhea compared to the placebo [ 69 ].

Investigating markers of gut permeability, West et al. Lamprecht et al. Zonulin concentrations decreased significantly from slightly above normal into the physiological range in subjects that supplemented with the probiotics.

Zonulin is a protein of the haptoglobin family released from liver and intestinal epithelial cells and has been described as the main physiological modulator of intercellular tight junctions [ ].

Increased zonulin concentrations are related to changes in tight junction competency and increased GI permeability [ ]. Shing et al. To assess GI permeability, subjects ingested lactulose and rhamnose before exercise and post-exercise urine was collected to measure the ratio.

Further, urinary claudin-3, a surrogate marker of gut barrier disruption, and serum lipopolysaccharide LPS were measured. There was no significant effect on lactulose:rhamnose ratio, urinary claudin-3 or serum LPS and it is possible that 4 weeks may not have been sufficient to detect changes.

In short-term, high dose single-strain probiotic supplementation L. casei , male runners under heat stress did not exhibit any marked changes in resting circulatory endotoxin concentration or plasma cytokine profile compared with placebo [ 76 ]. Conversely, Roberts et al.

However, no difference was identified in the assessment of intestinal permeability from urinary lactulose:mannitol ratio. This effect was reported both pre-race and 6 days post-race.

Additionally, seven highly-trained endurance athletes who received 4 weeks of L. salivarius UCC attenuated exercise-induced intestinal hyperpermeability [ ]. subtilis DE had no effect on gut permeability as measured by zonulin in Division I baseball players [ 83 ].

Given that different strains and product formulations exist, explaining the mechanism of action becomes a rather complex task. An additional challenge in probiotic research is that a mechanism of action involving the gut microbiota is not confirmed, or even examined, in the majority of cases and there certainly are mechanisms outside of the GI tract systemically and in other microbiota niches.

This shortcoming further emphasizes the need to not use the general term probiotics, when describing mechanisms of action, but try to specify the strains [ ]. This does not mean the mechanisms are the same for each strain, nor that precise mechanisms have been proven.

For example, bacterial strains such as L. reuteri SD ATCC and L. reuteri RC are different genetically and functionally, with the former producing reuterin believed to be important for inhibition of pathogens in the gut [ ] and the latter producing biosurfactants that inhibit attachment of uropathogens [ ].

Finally, several food products and dietary supplements may contain multiple species and strains in the same product. To fully explain the in-depth mechanisms of action is both out of the scope of this Position Statement and poorly understood in general.

However, interested readers are directed to other resources [ , ]. The question whether multi-strain or multi-species probiotics are better than single strain or single species probiotics depends on the outcome measure, dosage, and study population.

Potential additive or even synergistic benefits would need to be validated in a control clinical study, and currently those data do not exist. Mechanisms of action in relation to the effects of probiotic supplementation in athletes has been less described [ 40 ].

Here we discuss support of the gut epithelial barrier, increased adhesion to intestinal mucosa, the effects of postbiotics, modulation of the immune system, and improved nutrient absorption. The intestinal barrier is a major defense mechanism used to maintain epithelial integrity and protect the host from the environment.

Defenses of the intestinal barrier consist of the mucous layer, antimicrobial peptides, secretory IgA and the epithelial junction adhesion complex [ ].

Once this barrier function is disrupted, bacterial and food antigens can reach the submucosa and induce inflammatory responses [ , ]. Consumption of non-pathogenic bacteria can contribute to intestinal barrier function, and probiotic bacteria have been extensively studied for their involvement in the maintenance of this barrier.

However, the mechanisms by which probiotics enhance intestinal barrier function are not fully understood. Anderson et al.

Probiotics may promote mucous secretion as one mechanism to improve barrier function and the exclusion of pathogens. Several Lactobacillus species have been noted to increase mucin expression in human intestinal cell lines and, in the case of a damaged mucosa, may thus help restoration of the mucus layer.

However, this protective effect is dependent on Lactobacillus adhesion to the cell monolayer, which likely does not occur in vivo [ , ].

Therefore, mucous production may be increased by probiotics in vivo, but further studies are needed to make a conclusive statement. Strenuous and prolonged exercise place stresses on the GI tract that increase the likelihood of discomfort, abdominal cramping, acid reflux heartburn , nausea, vomiting, diarrhea, and permeability of the gut that may allow endotoxemia to occur [ 41 ].

Splanchnic hypoperfusion leading to ischemia in the gut is accepted as a principal cause, with additional contributions from nutritional, mechanical e. Probiotic support to increase resilience of the GI tract against ischemia is of interest to athletes, particularly for those involved in prolonged endurance events that have the greatest occurrence of GI problems that can impair or stop performance.

Mechanistically, prolonged or strenuous exercise may increase key phosphorylation enzymes [ ], disrupting tight junction proteins claudin influenced by protein kinase A and occludin influenced by both protein kinase C and tyrosine kinase.

Acute changes in tight junction permeability and paracellular transport may lead to a greater prevalence of systemic LPS. LPS from Gram-negative intestinal bacteria may provoke immune responses and endotoxin-associated symptoms characteristic of GI complaints often experienced in runners [ ].

LPS translocation across the GI tract can provoke systemic immune reactions with varied consequences [ ]. This sequence is considered a protective mechanism to minimize bacterial entry across the GI tract.

Under normal physiological conditions, endotoxins from gram negative bacteria are usually contained locally, with only relatively small quantities entering the systemic circulation. However, when GI defenses are either disrupted i. This effect could have implications for daily recovery strategies throughout prolonged training periods, and in the days following ultra-endurance events.

Roberts et al. Indeed, as LPS types vary across Gram-negative bacteria species, some LPS are poorly sensed by TLR4 and may have more direct impact on NF-κB activation [ ]. Specifically, the provision of bacteria belonging to the Lactobacillus genus may work by activating TLR2 and hence produce more favorable innate immune responses [ , ].

A mechanistic explanation for an improved intestinal barrier function after probiotic treatment is provided by Karczewski et al. TLR2 is localized in the membranes of intestinal wall cells and from there communicates with microbial products from Gram-positive bacteria [ ].

Furthermore, activation of the TLR2 signaling pathway can enhance epithelial resistance in vitro [ ]. Therefore, supplemented probiotics may suppress bacteria that activate the zonulin system e. Gram-negative bacteria , settle in the deep intestine, and activate the TLR2 signaling pathway.

The mechanisms used by one species of bacteria to exclude or reduce the growth of another species include: creation of a hostile microecology, elimination of available bacterial receptor sites, production and secretion of antimicrobial substances and selective metabolites, and competitive depletion of essential nutrients [ ].

Adhesion of probiotics to the intestinal mucosa has been shown to favorably modulate the immune system [ , ] and pathogen antagonism [ ]. In addition, probiotics are able to initiate qualitative alterations in intestinal mucins that prevent pathogen binding [ ] while some probiotic strains can also induce the release of small peptides or proteins i.

Specific adhesiveness properties related to the interaction between surface proteins and mucins may inhibit the colonization of pathogenic bacteria and are a result of antagonistic activity by some strains of probiotics against adhesion of GI pathogens [ ].

For example, lactobacilli and bifidobacteria can inhibit a broad range of pathogens, including E. coli , Salmonella, Helicobacter pylori, Listeria monocytogenes , and Rotavirus [ , , , , , , ]. To gain a competitive advantage, bacteria can also modify their environment to make it less suitable for their competitors, such as producing antimicrobial substances i.

Some lactobacilli and bifidobacteria share carbohydrate-binding specificities with certain enteropathogens [ , ], which makes it possible for the strains to compete with specific pathogens for the receptor sites on host cells [ ].

In general, probiotic strains are able to inhibit the attachment of pathogenic bacteria by means of steric hindrance at enterocyte pathogen receptors [ ].

Several compounds have been collected from several bacteria strains including SCFAs, enzymes, peptides, teichoic acids, peptidoglycan-derived muropeptides, endo- and exo-polysaccharides, cell surface proteins, vitamins, plasmalogens, and organic acids [ , , ].

Despite the fact that the mechanisms implicated in the beneficial health effects of postbiotics are not fully elucidated, they possess different functional properties including, but not limited to, antimicrobial, antioxidant, and immune modulation [ 4 ].

In the majority of cases, postbiotics are derived from Lactobacillus and Bifidobacterium species; however, Streptococcus and Faecalibacterium species have also been reported as a source of postbiotics [ , ]. SCFAs produced by the gut microbiota act as signaling molecules improving regulation of lipid metabolism, glucose homeostasis, and insulin sensitivity through the activation of receptors such as G protein-coupled receptors GPRs to regulate of energy balance while maintaining metabolic homoeostasis [ , ].

Specific SCFAs e. butyrate, acetate and propionate also contribute to plasma cholesterol homeostasis in rodents and humans [ ]. Some studies [ , , ] determined that cell-free extracts from lactic acid bacteria exhibit higher antioxidant capacity than whole cell cultures, suggesting that the antioxidant capacity could be attributed to both enzymatic and non-enzymatic intracellular antioxidants.

Through postbiotic action, it seems plausible that probiotics can increase exercise performance as seen through a delay in fatigue in athletes by virtue of their production of SCFAs. In addition, species within the Lactobacillus genus synthesize lactic acid, which is converted to butyrate and later to acetyl-CoA, which is used in the Krebs Cycle to generate adenosine triphosphate ATP.

However, these processes occur mostly in the gut so whether or not this would impact skeletal muscle performance remains to be determined [ ]. Another mechanism is by antioxidant action, which can attenuate muscle injury induced by reactive oxygen species, among others [ 92 ]. Antioxidant effects found in probiotics are linked to the synthesis of antioxidant substances such as vitamins B1, B5 and B6 [ ].

Moreover, probiotic supplementation reduces the risk of developing hyperglycemia, a condition known to be linked to oxidative stress [ , ]. Finally, the improvement in intestinal homeostasis, including the absorption process, may favor the absorption of antioxidants, increasing the availability of these substances [ 58 ].

Organic acids, in particular acetic acid and lactic acid, have a strong inhibitory effect against Gram-negative bacteria, and are considered the main antimicrobial compounds responsible for the inhibitory activity of probiotics against pathogens [ , , ].

The undissociated form of the organic acid enters the bacterial cell and dissociates inside its cytoplasm. The eventual lowering of the intracellular pH or the intracellular accumulation of the ionized form of the organic acid can lead to the death of the pathogen [ ].

Intestinal bacteria also produce a diverse array of health-promoting fatty acids. Certain strains of intestinal bifidobacteria and lactobacilli can produce conjugated linoleic acid CLA , a potent anti-carcinogenic agent [ , ].

An anti-obesity effect of CLA-producing L. plantarum has been observed in diet-induced obesity in mice [ ]. Recently, the ability to modulate the fatty acid composition of the liver and adipose tissue of the host upon oral administration of CLA-producing bifidobacteria and lactobacilli has been demonstrated in a murine model [ ].

Finally, certain probiotic bacteria are able to produce so-called de-conjugated bile acids, which are derivatives of bile salts. De-conjugated bile acids show a stronger antimicrobial activity compared to that of the bile salts synthesized by the host organism [ ].

Numerous studies have shown that prolonged intense physical exercise is associated with a transient depression of immune function in athletes. While moderate exercise beneficially influences the immune system [ ], a heavy schedule of training and competition can impair immunity and increase the risk of URTIs due to altered immune function [ , , ].

Both innate immunity and acquired immunity are decreased following prolonged exercise [ , , ]. It is well known that probiotic bacteria can exert an immunomodulatory effect; however, research from non-athletic populations may not be translatable to athletes.

Further, the manipulation and control of the immune system by probiotics is difficult to evaluate and make general conclusions. However, several studies investigating the effects of probiotics in athletes have reported improvement in low-grade inflammation [ 42 , 63 ], as well as increased resistance to URTIs [ 57 , 60 , 69 , 78 ] and reduced duration of URTI [ 79 ].

Modulation of the immune system to increase defenses against URTIs currently is the most extensively researched area. The GI tract is a major gateway for pathogen entry, and as such, is heavily protected by the immune system.

The immune system can be divided between the innate and adaptive systems. The adaptive acquired immune response depends on B and T lymphocytes, which are specific for particular antigens.

In contrast, the innate immune system responds to common structures called pathogen-associated molecular patterns PAMPs shared by the vast majority of pathogens [ ]. The primary response to pathogens is triggered by pattern recognition receptors PRRs , which bind PAMPs.

The best-studied PPRs are TLRs. In addition, extracellular C-type lectin receptors CLRs and intracellular nucleotide-binding oligomerization domain-containing protein NOD-like receptors are known to transmit signals upon interaction with bacteria [ ]. It is well established that probiotics can suppress intestinal inflammation via the downregulation of TLR expression, secretion of metabolites that may inhibit TNF-α from entering blood mononuclear cells, and inhibition of NF-ĸB signaling in enterocytes [ ].

Probiotics can enhance innate immunity first-line-of-defense by upregulating immunoglobulins, antimicrobial proteins, phagocytic activity, and natural killer cell activity, and enhance acquired immunity by improving antigen presentation and function of T and B lymphocytes to neutralize pathogens and virally-infected cells [ 10 , ].

The majority of placebo-controlled clinical trials assessing the efficacy of probiotics for reducing incidence, duration, and severity of URTI in athletes report beneficial outcomes. However, many different probiotics have been used and the differences in trial protocols and outcome measures complicate the drawing of more specific conclusions.

Supplementation with some probiotic strains has been suggested to improve dietary protein absorption and utilization [ ]. While not fully elucidated, several studies indicate a plausible role [ ], yet a clear mechanism of action is lacking. As noted, probiotics can potentially improve intestinal barrier function by modulating tight junction permeability which may improve nutrient absorption.

Improving the digestibility of protein can speed recovery of strength after muscle-damaging exercise [ ], and promote glycogen replenishment after exercise.

coagulans produce digestive enzymes [ 97 ] active under gut conditions alkaline proteases. These proteases can digest proteins more efficiently than the endogenous human proteases alone [ 96 ].

coagulans GBI, enhances the health of the cells of the gut lining improving nutrient absorption including minerals, peptides, and amino acids by decreasing inflammation and encouraging optimum development of the absorptive area of the villi [ 98 ].

In a computer-controlled in vitro model of the small intestine, B. coagulans GBI, enhanced amino acid absorption while improving colon health [ ]. In recreationally-trained males, Jäger et al. Furthermore, Toohey et al. However, each strain is unique with respect to how it responds to and affects the host.

However, the mechanisms by which probiotics enhance intestinal barrier function are not sufficiently studied. Probiotics also cause alterations in intestinal mucins that prevent pathogen binding. The concept of probiotics is not new. Around Nobel laureate, Elie Metchnikoff, discovered that the consumption of live bacteria L.

bulgaricus in yogurt or fermented milk improved some biological features of the GI tract [ ]. Bacteria with claimed probiotic properties are now widely available in the form of foods such as dairy products and juices, and also as capsules, drops, and powders.

Probiotics have been used safely in foods and dairy products for over a hundred years. Some of the most common commercially available strains belong to the Lactobacillus and Bifidobacterium genera. In this respect, well-studied probiotic species include Bifidobacterium ssp.

adolescentis, animalis, bifidum, breve, and longum and Lactobacillus ssp. acidophilus, casei, fermentum, gasseri, johnsonii, reuteri, paracasei, plantarum, rhamnosus , and salivarius [ ].

An international consensus statement in indicated that these are likely to provide general health benefits such as normalization of disturbed gut microbiota, regulation of intestinal transit, competitive exclusion of pathogens, and production of SCFAs [ 1 ].

Beyond athletes and physically active individuals, there is a large body of preclinical and clinical research on the GI benefits of probiotics in healthy individuals and in a wide range of health conditions.

These applications include treatment and prevention of acute diarrhea, prevention of antibiotic-associated diarrhea, treatment of hepatic encephalopathy, symptomatic relief in irritable bowel syndrome, and prevention of necrotizing enterocolitis in preterm infants [ ].

Overall, probiotics have an excellent safety profile with a large majority of clinical trials involving probiotics not giving rise to major safety concerns [ ]. Of the adverse events AEs commonly reported, Marteau [ ] outlined four classes of possible side effects of probiotic use: systemic infections, detrimental metabolic effects, cytokine-mediated immunologic adverse events in susceptible individuals, and transfer of antibiotic resistance genes.

Of these, particular concern relates to probiotics potential to create not improve or treat systemic infections [ 49 , 64 , ]. Further, probiotics have been studied in vulnerable groups, including infants, patients with severe acute pancreatitis, inflammatory bowel diseases, liver diseases, HIV, and other conditions [ , , , ] with even greater cause for concern with the small number of products that contain high concentrations of up to — billion live bacteria per dose [ ].

Many of the studies reporting AEs rarely serious AEs either do not utilize the appropriate biological sampling and identification techniques or AEs are poorly reported. Commercially available probiotic products can be divided into single-strain defined as containing one strain of a well-defined microbial species and multi-strain containing more than one strain of the same species or genus.

The term multispecies is also used for products that contain strains from more than one genus [ ], for example a product with a L. acidophilus strain, a L. reuteri strain, and a B. longum strain. Treatment with probiotics may involve the consumption of large quantities of bacteria, so safety is a primary concern.

There are two aspects to safety: establishing the adverse effect profile of specific single-strain and multi-strain supplements i. Safety assessments should take into account the nature of the specific probiotic microbe, method of administration, level of exposure, health status of the recipients, and the physiological functions the microbes are intended to perform [ ].

However, most probiotics in commercial use are derived from fermented foods with a long history of safe consumption, or from microbes that may colonize healthy humans [ ]. All common probiotic species are considered safe for the general population by the European Food Safety Authority EFSA , although this definition does not provide guidance on the increasing use of probiotics in people with medical conditions.

Moreover the benefits of probiotics are not validated by EFSA, jeopardizing the use of the term probiotic without an approved claim with some exceptions such as in Italy, Czech Republic, and Bulgaria [ ].

The approach is based on experience that for selected organisms there are no reasonable safety concerns for human health. The list regularly monitors the body of knowledge through extensive scientific literature review, applied to a wide array of micro-organisms added in the food-chain.

The QPS list concerns consumption by the general healthy population and does not take into consideration potential risks for vulnerable populations and this is clearly mentioned. The U.

Food and Drug Administration FDA classifies probiotics individually but has classified many as Generally Recognized As Safe GRAS , safe for the use in foods and infant products [ ]. The general consensus is that probiotic ingestion is safe [ , ], with large doses well tolerated and failing to exhibit any toxicity [ ].

Indeed, low CFU dosage and intervention periods between 2 weeks to 6 months are generally used within clinical research models [ , ]. In this position stand, which reviews studies focused on probiotic supplementation in athletes and physically active individuals, 11 studies measured AEs and general supplementation tolerance, while 30 studies did not.

Of the 11 studies, a general consensus was made to conclude that probiotic supplementation was generally well tolerated with a very low level of adverse health effects. There was one instance in which mild GI symptoms 5 episodes were reported, including flatulence and stomach rumbles during supplementation with a multi-strain probiotic in 22 active individuals [ 66 ].

AEs are often not well recorded in nutritional studies in general and probiotics are no exception to this. Overall, from the current body of research probiotic supplementation for healthy athletes and physically active individuals appears safe.

Caution is warranted for those with serious health conditions, such as severe acute pancreatitis, inflammatory bowel diseases, liver diseases, and HIV.

In these instances, it is advised that the patient consult with their health care practitioner before supplementing. Another consideration is supplementing evidence-based dosages and keeping the probiotic properly stored. Unlike, other familiar sports supplements, probiotics are live organisms and may require specific storage requirements including refrigeration.

acidophilus, casei, fermentum, gasseri, johnsonii, reuteri, paracasei, plantarum, rhamnosus, and salivarius. In these instances, patients should consult with their health care practitioner before supplementing. Currently there is no clear set of recommendation or guidelines on probiotic use for athletes.

The effects of probiotics are strain specific, and therefore, strain identity is important to link to a specific health effect as well as to enable accurate surveillance and epidemiological studies.

Unfortunately, government regulatory organizations are highly varied across national borders and jurisdictions in regulation of probiotics, making uniform recommendations difficult. The proposed guidelines recommend: 1 identifying of the genus and species of the probiotic strain by using a combination of phenotypic and genotypic tests as clinical evidence suggesting that the health benefits of probiotics may be strain specific, 2 in vitro testing to delineate the mechanism of the probiotic effect, and 3 substantiating the clinical health benefit of probiotic agents with human trials.

Additionally, safety assessment of the probiotic strain should at a minimum determine: 1 patterns of antimicrobial drug resistance, 2 metabolic activities, 3 side effects noted in humans during clinical trials and after marketing, 4 toxin production and hemolytic potential if the probiotic strain is known to possess those properties, and 5 lack of infectivity in animal studies [ ].

The regulation of probiotics differs between countries as there is no universally agreed framework. For the most part, probiotics are categorized as food and dietary supplements because most are delivered by mouth as a food or supplement. For example, Health Canada has provided a Natural Health Product monograph that includes dosage form s , use s or purpose s recommended as well as minimum quantities for L.

pylori infections, 1. The minimum daily dose is the sum of CFU per day provided by all live microorganisms that are present in the product, and not the minimum amount of CFU per day for each of the microorganisms.

Further, a duration of use statement is not required, nor is there any guidance provided. In Canada, probiotics have two modes of sale on the market, Natural and Non-Prescription Health Products Directorate NNHPD and Food Directorate [ 3 , ].

Health Canada uses a pre-market approval process for non-food like applications such as capsules, tablets, softgels and powders which requires companies to acquire a Natural Product Number NPN prior to bringing to market [ 3 ]. Table 5 below details the current licensed products and claims specific to sport performance using probiotic strain s in or outside the pre-approved monograph.

This list is open access through the Health Canada LCNHPD Licensed Natural Health Products Database which allows consumers and retailers the ability to review claims on packaging to approved claims by the NNHPD [ ].

Japan is viewed by many to be a global market leader given that probiotics are available as both foods and drugs [ ], and was the first global jurisdiction to implement a regulatory system for functional foods and nutraceuticals in Under Japanese regulations, probiotic products are in a distinct category of foods known as Foods for Specific Health Uses FOSHU.

For probiotic food products, efficacy claims are prohibited on the labeling. If claims are to be made about efficacy, one must obtain special permission from the Ministry of Health and Welfare MHLW for the product to be considered FOSHU, for which substantiation of efficacy and safety is a mandatory requirement [ ].

In Brazil, probiotics are considered as functional foods, and considered to be different from food. But legislation asks for safety and efficacy demonstration of food products and hence all these products must be registered and approved by a health authority called National Health Surveillance Agency Brazil ANVISA [ ].

All health claims for probiotics have to be authorized by EFSA which has issued a list of microbial cultures that have a Qualified Presumption of Safety [ ], meaning that they do not require safety assessments.

The EFSA is also responsible for assessing health claims made for probiotic products. So far, EFSA has rejected all submitted health claims for probiotics. While rigorous scrutiny of product claims is apparent, there appears to be little regulation of the manufacturing process and almost no post-marketing regulatory follow-up [ ].

In the United States, government regulation of probiotics is complex. Many probiotics are sold as dietary supplements, which do not require FDA approval before they are marketed. Further, dietary supplements are required to comply with Good Manufacturing Practice guidelines, but these do not extend to testing quality or efficacy [ ].

From the examples provided, it is apparent that the current approach to regulation is inadequate and can lead to problems of quality, safety, and claim validity in commercial probiotic products used in a medical context, including those used in vulnerable populations [ ].

In January , the Council for Responsible Nutrition CRN and the International Probiotics Association IPA announced the development of scientifically-based best practices manufacturing guidelines for the labeling, storing, and stability testing of dietary supplements and functional foods containing probiotics [ ].

These guidelines were designed to facilitate transparency and consistency in the probiotic sector. A key element of the guidelines is labelling probiotic products in CFU, the scientifically accepted unit of measure for probiotics and used to report probiotic quantity in many studies conducted to assess the safety or benefits of probiotics.

Consistent with scientific literature, CFU are commonly used on probiotic product labels in many jurisdictions around the world to help consumers and healthcare professionals identify products providing probiotics in amounts shown to have benefit.

However, United States regulations require dietary ingredients with the exception of some vitamins be labeled by weight. Labeling probiotic quantity by weight is not meaningful because this measure does not indicate the viability of the microorganisms in the product throughout shelf life.

To the contrary, CFU are more representative of the quantity of viable microorganisms and gives consumers and healthcare professionals accurate information.

The FDA has recently agreed that in addition to weight, probiotic amounts can also be labelled in CFU. The dose of probiotic administered is an important factor to be considered.

In our review, we report a wide range of doses Table 4 , and in several studies the dosage was not reported. Similar to the type of probiotic used, the duration of supplementation has also been variable in the studies reviewed Table 3.

The duration and consistency of probiotic supplementation are important factors. Coqueiro et al. Therefore, studies that supplement for a similar or shorter period should be evaluated with caution. With the interruption of probiotic intake, there is a reduction in the microorganism administered in the colon, and with 8 days of supplementation discontinuation, the probiotic is no longer detectable in the gut [ ].

Finally, there is some limited evidence that discrepancies exist between males and females, even after supplementation of probiotics with the same dose [ 61 ]. Future studies are needed in this area, with the intention of establishing a recommendation for each sex.

Future research is needed in this area. Overall, the effects of probiotics in athletes have received less attention compared to animal studies and human clinical conditions in the general population. Clearly, the focus of the research community has been investigating the beneficial effects of probiotics on gut and immune health in various subgroups of the general population.

In animals, probiotics have been associated with benefits including normalizing age-related drops in testosterone levels [ ], increasing neurotransmitter synthesis [ ], reducing stress-induced cortisol levels [ ], reducing inflammation [ ] and improving mood [ ].

However, all these potential benefits lack current substantiation in human intervention trials in an athletic population.

Here we discuss future research opportunities to explore in relation to the microbiome and athletes. It is well known that to increase levels of muscle mass, resistance training must be included in exercise regimens.

Probiotic supplementation, both with and without resistance training, can decrease levels of body weight and fat mass in overweight and obese individuals, as well as female athletes [ , , ].

Increases in fat free mass, however, have only been shown in animal models. Chen and colleagues [ 92 ] supplemented male Institute of Cancer Research ICR strain mice with L.

plantarum TWK10 for 6 weeks. Mice were divided into three groups and daily doses of 0, 2. The dosages chosen were modified from a comparable human dose equivalent to mouse body size.

Additionally, the number of type I fibers were increased significantly. Mechanistically, it is plausible that Lactobacillus strains decrease levels of inflammation, thereby decreasing activation of intracellular proteins linked to muscle atrophy, which may eventually link to an observed increase in muscle mass.

Chen et al. Though improvements in body composition have been shown in humans, more studies examining decreased inflammation as a mechanism to increase muscle mass, in conjunction with reduction in fat mass, is warranted. Physiological fatigue, such as extreme fatigue after exercise, is accompanied by poor athletic performance and loss of favorable working conditions for tissues [ ].

In response to higher intensity exercise, the concentration of lactate and hydrogen ions increased markedly resulting in an acidification in muscle and subsequent fatigue [ , ].

Probiotic supplementation may have potential to remove and utilize blood lactate after exercise. For instance, most Lactobacillus species produce lactic acid, which could facilitate the production of butyrate by lactate-utilizing bacteria that first produce acetyl-CoA from lactate [ ].

In the classical pathway, the enzymes phosphotransbutyrylase and butyrate kinase convert butyryl-CoA to butyrate and coenzyme A with concomitant formation of ATP. Thus, probiotics and the gut microbiota could play important roles in maintaining normal physiology and energy production during exercise.

Several animal studies have been conducted with promising results. In mice who consumed a probiotic kefir daily over 4 weeks, swimming time-to-exhaustion was significantly longer, forelimb grip strength was higher and serum lactate, ammonia, blood urea nitrogen BUN , and creatine kinase levels were lower after the swimming test [ ].

In mice supplemented with L. plantarum TWK10 over 6 weeks, supplementation dose-dependently increased grip strength and endurance swimming time and decreased levels of serum lactate, ammonia, creatine kinase, and glucose after an acute exercise challenge [ 92 ].

Furthermore, the number of type I fibers in gastrocnemius muscle significantly increased with LP10 treatment. In a six-week human double-blind placebo-controlled clinical study, young healthy amateur runners supplemented with L.

plantarum TWK10 and underwent an exhaustive treadmill exercise measurements and related biochemical indexes [ 85 ]. Together, these studies suggest a role in which certain probiotics may enhance energy harvesting, and have health-promotion, performance-improvement, and anti-fatigue effects.

These are areas that may warrant further research consideration. Several important methodological shortcomings in research design should be addressed to improve scientific evidence for the biological and clinical benefits of probiotics.

For example, discrepancies between men and women, even after supplementation of probiotics with the same dose, are evident [ 61 ]. In this sense, in studies with both sexes, conflicting results may occur. In many instances and products, the recommendation for probiotic supplementation is no different for men and women, necessitating studies investigating this topic, with the intention of establishing a recommendation for each sex.

Other design concerns include the relatively small number of subjects, which may compromise the accuracy and interpretation of results. Thus, studies that supplement for a similar or shorter period should be evaluated with caution. Further, with the interruption of probiotic intake, there is a reduction in the microorganism administered in the colon, and with 8 days of supplementation discontinuation, the probiotic is no longer detectable in the gut [ ].

Since many effects are dose-dependent, the amount of probiotic administered is an important factor to be considered. Most of the studies do not control for previous levels of physical activity, so individuals within the same study may have very different levels of physical activity, making comparisons unrealistic.

Finally, very few studies have evaluated the performance in strength exercises after supplementation with probiotics and this is an important area of sports and physical training to be studied. Oral supplementation with selective bacteria holds promise in positively affecting the endocrine system.

In mice, the microbiota can regulate testicular development and function [ ], while androgen deficiency has substantially altered the microbiome [ ]. Supplementation with a selenium-enriched probiotic in conjunction with a high-fat diet in male mice significantly alleviated the adverse effects of hyperlipidemia by reducing testicular tissue injury, increasing serum testosterone levels, and improving sperm indexes [ ].

Further, aging mice supplemented with the probiotic bacterium L. reuteri had larger testicles and increased serum testosterone levels compared to their age-matched controls [ , ].

In a human pilot study, supplementation with L. acidophilus and B. However, another pilot study supplementing a probiotic and prebiotic L. Interestingly, Tremellen et al. Endotoxin can reduce testosterone production by the testes, both by direct inhibition of Leydig cell steroidogenic pathways and indirectly by reducing pituitary luteinizing hormone drive and sperm production [ ].

Tremellen and colleagues [ ] theorized the male reproductive axis has evolved the capacity to lower testosterone production during times of infection and resulting endotoxin exposure, decreasing the immunosuppressive influence of testosterone, in turn enhancing the ability to fight infection.

Weight loss and physical activity seem to improve these symptoms [ ]. However, studies are severely lacking. In the future, larger sample sizes and more robust study designs will be needed.

There is an increasing interest in supplementation with non-viable microorganisms or microbial cell extracts. By definition, probiotics are required to be alive, therefore inactivated microorganisms cannot be classified as such.

However, preparations from certain probiotic species and strains such as those from lactobacilli and bifidobacteria have shown to maintain health benefits even after no longer being viable [ , , ]. Inactivation can be achieved by different methods, including heat, chemicals e.

Importantly, these methods of inactivation may affect structural components of the cell differently, and therefore their biological activities [ , ]. Piqué et al. Favorable properties of heat-killed bacteria have been observed in vitro [ ], in animal models [ ], and human trials [ , ].

For example, in healthy subjects with high levels of self-reported psychological stress, supplementation with heat-killed L. This finding may have resulted from innate immunity stimulation as heat-killed L. plantarum L has been reported to enhance type I IFN production in humans [ ].

Compared to placebo, supplementation increased the maturation marker of plasmacytoid DC pDC CD86 , responsible for the antiviral response, and decreased the cumulative days of URTI symptoms. Furthermore, ingestion decreased cumulative days of self-reported fatigue.

In a longer duration randomized, double blind, placebo-controlled study, 49 long-distance runners consumed heat-inactivated L. No significant difference in physical performance between the CP and placebo group were detected.

However, CP supplementation improved recovery from fatigue and relieved anxiety and depressive mood compared with placebo intake.

Further, CP intake prevented training-induced reduction of hemoglobin and facilitated exercise-induced increase in serum growth hormone levels. Moreover, gene expression profiling of peripheral blood leukocytes indicated that CP prevented the stress-induced changes in the expression of genes related to mitochondrial functions.

In relation to the gut microbiota, CP intake increased the alpha- and beta-diversity, and the compositions of Bifidobacterium and Faecalibacterium. These compositional changes in the gut microbiota may have contributed to the recovery of fatigue and moderation of stress and anxiety through the gut-brain axis.

Indeed, inactivated CP can relieve stress in healthy young adults facing stressful conditions [ ]. While encouraging, it is unclear how the daily intake of the heat-inactivated probiotics could affect the gut-brain axis and alter stress responses. Further research investigating potential mechanisms as well as more extensive studies with a wider range of athletes and exercise loads should be conducted.

In addition, primary aims related to GI tract health and exercise performance should be more thoroughly assessed. Physical health and mental health are strongly linked with depression, which is recognized as a leading cause of disability throughout the world [ ].

As reported by Clarke et al. The gut-brain axis is a bidirectional pathway via the neural, endocrine, and immune systems. The mechanisms by which probiotics improve symptoms of depression and other mood disorders are via anti-inflammatory actions that reduce activity of the hypothalamic-pituitary-adrenal HPA axis [ ].

Probiotics may be an effective treatment strategy for depression and mood disorders such as anxiety given the link between GI tract bacteria and the brain i. the gut-brain axis , as decreased intestinal dysbiosis may have beneficial effects on mood.

Only a few studies have been completed in human subjects that have examined the impact of probiotic supplementation on mood and anxiety. casei had positive effects on mood, with subjects feeling increased clear-headedness, confidence, and elation compared to baseline.

A study by Rao et al. casei given to individuals with chronic fatigue syndrome reduced anxiety symptoms. Similarly, Messaoudi and others [ ] found decreased anxiety related behaviors after 2 weeks of a combination of L. helveticus and B. longum in 25 healthy adults.

fermementum LF16, L. rhamnosus LR06, L. There are a ton of different types of probiotics found naturally occurring in foods and in supplements, and the effects may vary depending on the type of probiotic you consume, the NIH suggests.

Other bacteria and yeasts may also be used in probiotic products. The only way you could really figure out the best type of probiotic for you would be by getting a stool test to see which bacteria you could use more of, he says.

It may also play a key role in controlling inflammation and oxidative stress on the body—ultimately resulting in enhanced recovery. Sports nutritionist Barbara Lewin , R. It takes quite a while for probiotics to actually make a change in your GI tract, says Stefanaski. At least not yet. Then, depending on the person and their bigger health picture, he may suggest a probiotic supplement or refer them to a functional medicine practitioner if they need some more targeted help figuring out the optimal way for them to get good bacteria in their guts.

Opt for yogurt varieties that are low in sugar think: plain flavors —the sweet stuff can disrupt your microbiome, says Seebohar. You can also try eating more foods with added probiotics to boost your intake.

Probiotic granola—like this one from Purely Elizabeth —is an option, too. You can even find probiotics in some recovery drinks, like this one from Skratch Labs. At the end of the day, know that probiotics may give you a bit of a boost, but they should never replace your other recovery efforts, like properly hydrating, fueling, and sleeping.

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Probiotic supplements for athletes

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