Bifidobacteria digestive health Lactobacilli prebiotics probiotics Symbiotics Training Benefits yeast Nutrition

Probiotics- What’s in it for You?

Stacey Penney
Stacey Penney

Not quite sure what all the lingo means when you are choosing your morning yogurt? Do you need a probiotic? How about adding in a prebiotic? Here we’ll set the stage on what probiotics are and their potential to improve health and performance.

Probiotics are foods that contain live microorganisms, such as yeast, Lactobacilli, Bifidobacteria, and other specific strains of beneficial bacteria (1). They are most active in the small intestines, and there is strong support that probiotics may improve digestive health and immunity function. You’ll find probiotics in some yogurts and other cultured dairy products.

Prebiotics are a nondigestible food product for the probiotics. These include inulin, fructo-oligosaccharides, and polydextrose, which can be found in whole grains, onions, garlic, leeks, honey, along with some fruits (bananas) and fortified foods and beverages (1-2). Prebiotics are most active in the large intestines, and may improve gastrointestinal health and increase calcium and magnesium absorption (1,3).

Symbiotics are a combination of probiotics and prebiotics. They improve the probiotics ability to deliver health benefits because they contain live bacteria and the prebiotic fuel it needs to survive longer in the digestive system (2).

Consuming probiotics may positively impact the beneficial flora of the intestines, especially when the bacterial status of the system is out of balance. This imbalance can be influenced by such things as stress, alcohol use, illness, age, antibiotic use, content of and transit time through the gut (3-4).

Focusing here on athletes and very active clients, intense and prolonged training can suppress immune system function and increase susceptibility to upper respiratory tract infections (3-6). For example, there is a window of 3 to 72 hours following intense aerobic activity that leaves the immune system stressed, suppressed, and more susceptible to respiratory infections (5). For athletes in training, taking a daily probiotic reduced the frequency of upper-respiratory tract infections. Though not considered an ergogenic aid, if probiotics help to keep athletes healthy, we can probably assume this would only improve their training and performance (3).

Marathon runners and triathletes sometimes experience GI tract woes. But does consuming probiotics change the frequency of port-o-potty stops? Though not proven to prevent race day diarrhea episodes, it could shorten the time of GI episodes post-race (7).

Additional probiotic claims and possibilities for general health improvement continue to grow. Areas undergoing more research include (2-3,8):

  • Obesity and metabolic syndrome
  • Cholesterol-lowering effects
  • Lactose intolerance
  • Irritable bowel syndrome (IBS)
  • Constipation prevention
  • Colon cancer prevention

Probiotics are safe for most healthy adults and side effects are rare. Always check with your healthcare provider if you are considering adding supplements to your diet.


  1. Insel P., Ross D., McMahon K., et al. Nutrition. 4th ed. Sudbury, MA: Jones and Bartlett; 2011.
  2. Sekhon, B., & Jairath, S. (2010). Prebiotics, probiotics and synbiotics: an overview. Journal Of Pharmaceutical Education & Research, 1(2), 13-36.
  3. Nichols, A. W. (2007). Probiotics and Athletic Performance: A Systematic Review. Current Sports Medicine Reports (American College Of Sports Medicine), 6(4), 269-273.
  4. Gleeson, M., Bishop, N. C., Oliveira, M., & Tauler, P. (2011). Daily Probiotic's (Lactobacillus casei Shirota) Reduction of Infection Incidence in Athletes. International Journal Of Sport Nutrition & Exercise Metabolism, 21(1), 55-64.
  5. Nieman DC, Pedersen BK. Exercise and immune function recent developments. Sports Med. 1999;27(2):73-80.
  6. Brylee A., H., Katherine E., B., Dane, B., James, M., Phil, H., & Rachel C., B. (n.d). Original research: Probiotic supplementation reduces the duration and incidence of infections but not severity in elite rugby union players. Journal Of Science And Medicine In Sport, doi:10.1016/j.jsams.2013.08.004.
  7. Kekkonen, R. A., Vasankari, T. J., Vuorimaa, T., Haahtela, T., Julkunen, I., & Korpela, R. (2007). The Effect of Probiotics on Respiratory Infections and Gastrointestinal Symptoms During Training in Marathon Runners. International Journal Of Sport Nutrition & Exercise Metabolism, 17(4), 352-363.
  8. Mallappa, R. H., Rokana, N., Duary, R., Panwar, H., Batish, V., & Grover, S. (2012). Management of metabolic syndrome through probiotic and prebiotic interventions. Indian Journal Of Endocrinology & Metabolism, 16(1), 20-27.

Tags: Bifidobacteria Tags: digestive health Tags: Lactobacilli Tags: prebiotics Tags: probiotics Tags: Symbiotics Tags: Training Benefits Tags: yeast Tags: Nutrition

The Author

Stacey Penney

Stacey Penney

Stacey Penney, MS, NASM-CPT, CES, PES, CNC, is the Content Strategist with NASM and AFAA. A 20+ year veteran of the fitness industry, she's worked with the top certification and continuing education groups. At NASM and AFAA she drives the content for American Fitness Magazine, blog and the social media platforms. Stacey received her degree in Athletic Training/PE from San Diego State University and an MS in Exercise Science from CalU, plus credentials in Health Promotion Management & Consulting (UCSD), Instructional Technology (SDSU), group fitness and yoga. Previous San Diego Fall Prevention Task Force Chair, she’s developed continuing education curriculum for fitness organizations in addition to personal training, writing, and co-coaching youth rec soccer.