Will probiotics improve performance, impact immune function, or enhance overall health of the athlete?
By Katie Lamps
As an athlete, you are probably always looking for changes you can make to help improve performance and prevent illness and injury. Nutrition plays an integral role in each of these areas, which is why proper nutrition is so crucial for the athlete. There are certain components of athlete nutrition—such as adequate hydration to sustain activity—that have been extensively researched and have defined guidelines for practice. However, other areas are not so well-defined, including ergogenic aids and supplements that are on the market. One type of supplement that you may have heard of in recent years are probiotics. But just what are probiotics, how do they work, and can they help boost performance or risk harming the athlete? Read on to learn all about the pros and cons of probiotics for the athlete!
What are probiotics?
Probiotics are live microorganisms that are consumed in order to promote health in the individual. The term ‘probiotics’ covers a wide range of microorganisms, with the most common strains being the Lactobacilli and Bifidobacteria species. Different strains of probiotics may have different effects, although more research must be done to determine exactly which are beneficial and which are not. Probiotics can be found in capsules form, powder form, or in foods such as yogurt and fermented products like kefir, kimchee, and sauerkraut.
How do probiotics work?
Since the term probiotics can refer to a wide variety of strains, it makes sense that they have a variety of effects on the body. However, some strains of probiotics have been shown to help promote the “good” bacteria in your body, especially in the gut. You may also hear this community of microorganisms that lives in the human body be called the ‘microbiome’. Probiotics may help maintain a healthy microbiome, or may help the microbiome return to a healthy condition after being disturbed due to triggers such as illness, stress, or antibiotic use.
Maintaining a healthy gut microbiome is important because these “good” bacteria work to keep you healthy in many ways! Good bacteria can help support proper immune function, control inflammation, and maintain normal digestion and absorption.
What are the potential benefits for athletes?
In recent years, there has been research focusing specifically on the effect of probiotics and the athlete. One potential benefit of including probiotics is their effect on immune function. During intense exercise, an inflammatory immune response is triggered, which can increase harmful reactive oxygen species and mechanical damage. Furthermore, during lower-intensity endurance training, intestinal transit time is decreased, which can increase exposure to harmful pathogens in the gut and potentially increase susceptibility to illness. Probiotics can help modulate how the immune system reacts to these stressors and may help prevent the athlete from getting sick. So far, research is starting to suggest that probiotics may decrease risk of upper respiratory tract infections in athletes—although further research is needed to confirm what strains, dosage, and frequency of supplementation are needed.
The second main benefit that probiotics may have for athletes is reducing susceptibility to gastrointestinal symptoms such as nausea, bloating, cramping, and diarrhea. These negative effects can be seen in athletes participating in prolonged endurance events, such as cyclists, runners, and triathletes. These symptoms occur because blood flow is redirected from the gut to other areas of the body, such as the working muscles or to the skin for cooling purposes. Some studies have shown mild improvements with probiotic supplementation for prevalence or severity of GI symptoms, while others have shown no difference. Again, further research is needed to identify best practice recommendations for using probiotics to improve GI symptoms in athletes.
What are the potential cons for athletes?
While the body of research on the effectiveness of probiotics is still growing, it is of interest to note that the majority of studies are not really finding significant downsides to probiotic usage. One of the biggest drawbacks may simply be the lack of results—no one wants to spend money on a probiotic-rich food or supplement and then not find any benefits! Furthermore, in the United States, probiotics are frequently sold as dietary supplements—which means they don’t require approval by the U.S. Food and Drug Administration (FDA). There may be a risk of a probiotic supplement being contaminated with a prohibited ingredient that could show up on a drug screen. This risk can be minimized by choosing supplements with third party testing, or by choosing probiotic-rich foods such as yogurt rather than a supplement.
As far as other potential side effects of probiotics, the most commonly reported include increased flatulence and/or stomach rumbling during the colonization period that occurs when someone first begins probiotic supplementation. These effects can be mediated by beginning probiotics in the off-season, when you can time the start of probiotic use to avoid interference with training. Furthermore, anyone with a weakened immune system, chronic health conditions, or someone who is on other medications should consult a doctor before beginning probiotic use.
What about dosage and type of probiotic?
As you may be realizing, research regarding probiotic supplementation research is still new, and best practices for dosage and strain is still being determined. Current research focuses on the strains Lactobacilli and Bifidobacteria, so these are good strains to look for if you choose to use a supplement.
Dosages will vary. If using a supplement, research suggests that probiotics taken daily with 106 – 1010 Colony Forming Units (CFU) may exert beneficial effects. There are no current guidelines for how long the supplement should be taken, and long-term effects are unclear—most studies have a supplementation period of 4-16 weeks. Working with a dietitian in your off-season could help you determine your individual dose-response for probiotics, as well as help manage any potential side effects.
If choosing to use probiotic-rich foods instead, some good options include yogurt and fermented foods such as kefir, sauerkraut, kimchee, sourdough bread, kombucha, miso, and tempeh. Some aged cheeses such as cheddar or gouda also have probiotics. While there is no recommended daily allowance for probiotics, athletes may find that adding in one or two of these items per day may help them reap some benefits. Furthermore, these nutrient-rich foods are full of other important vitamins and minerals. Items such as yogurt, cheese, and tempeh can even help the athlete reach their protein goals!
Conclusion
Overall, research on the efficacy of probiotics is on-going. Potential benefits for athletes may include enhanced immune function and decreased severity or prevalence of GI symptoms. Therefore, athletes who may benefit the most from including probiotics include those that experience frequent or persistent cold and flu-like symptoms, or those that frequently experience troublesome GI symptoms.
Probiotic supplementation may be convenient, but they are not regulated by the FDA. Furthermore, there are currently no clear guidelines on what strain of probiotic, how much, and how often one should supplement. Therefore, if an athlete is interested in probiotics, it may be best to do so by adding probiotic-rich foods to their diet instead. These foods may lead to probiotic-related benefits—and even if they don’t, the athlete is still consuming protein, vitamins, and minerals from these products!
Interested in learning more about probiotics and how to add them to your diet? Have you heard about a different dietary supplement that may boost performance, but want to learn if it is safe and effective? Do you just want to figure out how to eat nutritiously to maximize your athletic performance? A Registered Dietitian and Certified Specialist in Sports Dietetics is the perfect person to ask! Reach out to Dr. Schubert here!
We offer additional information on related supplements like creatine, leucine/BCAAs, or vitamin D.
References:
- Probiotics. Cleveland Clinic Web site. https://my.clevelandclinic.org/health/articles/14598-probiotics#:~:text=The%20main%20job%20of%20probiotics,your%20body%20out%20of%20balance. Published March 9, 2020. Accessed August 31, 2020.
- Wang Y and Shurtleff D. Probiotics: What You Need to Know. https://www.nccih.nih.gov/health/probiotics-what-you-need-to-know. National Center for Complementary and Integrative Health. Published August 2019. Accessed August 31, 2020.
- West NP, Pyne DB, Peake JM, Cripps AW. Probiotics, immunity and exercise: a review. Exerc Immunol Rev. 2009;15:107-126.
- Pyne DB, West NP, Cox AJ, Cripps AW. Probiotics supplementation for athletes – clinical and physiological effects. European Journal of Sports Science. 2015;15(1):63-72.
- Moller GB, Goulart MJV da C, Nicoletto BB, et al. Supplementation of probiotics and its effects on physically active individuals and athletes: systematic review. International Journal of Sports Nutrition and Exercise Metabolism. 2019;29(5):481-492.