Taking care of your microbiota

Close your eyes and imagine yourself in the Amazon rainforest, lush and filled with a variety of trees, shrubs, and plants. This ecosystem is crucial for the survival of the species that live there.

Our gut flora is like this forest: unique and complex, living in symbiosis and offering protection against external attacks.

The microbiota is the collection of microorganisms (bacteria, fungi, viruses, and parasites) that line the walls of our small intestine and colon (large intestine). It weighs nearly 2 kg and, in a healthy person, is composed of approximately¹⁰¹⁴ differentbacteria(Landman & Quévrain, 2016)! Our body acts in symbiosis with this flora, and this interaction influences our health. What is fascinating is that each intestinal flora is unique, much like a fingerprint.

From the moment we are born, through contact with microorganisms left by our mother during childbirth and those in the external environment, we begin to form our microbiota. Under the influence of our diet, genetics, lifestyle, medical treatments, and the environment in which we live, our microbiota becomes denser and more complex from the earliest years of our lives. Later on, other factors, such as the action of our hormones and changes in our lifestyle (diet, illness, travel), will alter the quality and quantity of our flora. Recent studies have found significant differences between active and sedentary individuals. The younger we start exercising, the more diverse our flora will be, which can improve both our physical and mental health (Mika & Fleshner, 2016).

How can simple bacteria have such a big impact on our health? Mainly because they aid digestion, and when digestion is well regulated, we absorb nutrients better, indigestible residues ferment better, and the synthesis of many vitamins and the absorption of fatty acids are more efficient. Among other things.

When properly dispersed, bacteria also play a role in reducing inflammation, preventing certain intestinal diseases, and may even be linked to the onset or prevention of type 2 diabetes and obesity, in a multifactorial context.

It is therefore important to maintain the balance of our intestinal flora. How? Through our eating habits, which influence the quality of our microbiota. For example, a diet high in fat and low in fiber is associated with an imbalance in the intestinal flora—there are too many bad bacteria and not enough good ones. Other factors, such as excessive antibiotic use, intestinal diseases, and our environment (pollution, travel) can also influence our intestinal balance.

Parmi many bacteria that populate our intestines, probiotics are among those we want in large numbers, as they promote a healthy balance of intestinal flora. Although they are found in some foods, such as yogurt, kefir, cheese, and certain fortified juices, therapeutic strains—those that are truly effective—are mostly found in supplements sold at pharmacies, often in the form of drinkable yogurt. Dairy products remain the preferred vehicle for maintaining active probiotics.

To add a little complexity to the matter, there are many strains of probiotics, each with specific health benefits. Consuming probiotics without really knowing their roles and our needs is like walking into abike shopandwalking out with a mountain bike to ride in a criterium race. 

It is still too early to know the exact dose and frequency at which probiotics should be taken to see positive effects on our health or performance. However, we do know that a dose of at least 1 billionACTIVE bacteriaforat least 10 days per month appears to be effective, and that regular consumption may yield greater potential benefits.

Although there has been a lot of focus on probiotics in recent years, there has also been interest in the "food" for these bacteria that are beneficial to our health, namely prebiotics. These carbohydrates (oligosaccharides), which are indigestible by humans, help maintain and proliferate probiotics by feeding them in the digestive system. Much like the dietary fiber found in the skins of fruits and vegetables and in whole grains, prebiotics do not provide calories (energy) to humans, but are useful for keeping our probiotics "healthy." It is the probiotics that feed on them.

Sometimes added to foods, such as inulin in certain products, prebiotics are also naturally present in onions, asparagus, bananas, wheat, and rye. They come in two types: fructooligosaccharides (FOS) and galactooligosaccharides (GOS).

Athletes' immune responses are sometimes put to the test. Training loads can be excessive, sleep can be disrupted, psychological stress can be high, and changes in the environment can lead to more infections, particularly in the respiratory tract (hello, COVID-19 pneumonia!). Taking specific probiotic supplements (depending on the strain) could improve immune health in athletes by reducing the number, severity, and duration of these respiratory infections. It could also improve muscle fiber response to post-exercise recovery. But even more importantly, in the athletic community, taking probiotics could modulate body composition and lean mass, help reduce cortisol and lactate levels during exercise, and improve cognitive health and mood (Jäger et al., 2019).

The conditional applies here, as these effects are not so clear-cut in studies. More evidence is needed to better understand the role of probiotics on performance. So far, only one study has shown an improvement in aerobic performance when taking supplements. In this study, 30 athletes who consumed enriched yogurt for 30 days saw an improvement in their VO2max compared to the group without probiotics (Salehzadeh, 2015). Probiotics also appear to have had an impact on recovery, particularly by reducing pain, but only when the athlete's protein intake was adequate.

Considering all these potentially beneficial effects for athletes, but above all their safety from a medical point of view, it is not surprising that certain strains of probiotics are widely used by athletes. This constant intake couldpotentiallyimprovethe immune response, while helping to reduce the risk of illness both during training and competition. It should be noted that athletes should seek adequate information to find a probiotic strain that is recognized for its health benefits and validated by scientific research.

While many questions remain unanswered in terms of understanding the exact role of microbiota in performance, in the meantime, we have everything to gain by eating a balanced diet, maintaining a healthy lifestyle, and exercising. 

• Probiotics are not essential for athletic performance, but may be useful during periods of intense physical stress, competitions abroad, or changes in an athlete's lifestyle.
• Effective strains are available in pharmacies and not in commercially available food products.
• Prebiotics are found naturally in many foods rich in fiber, vitamins, and minerals. They help regulate probiotics and optimize them.
• Certain factors or habits (external environment, antibiotic use, ultra-processed foods) can harm the health of the microbiota... and therefore our health and performance.
• It is important to choose a strain of probiotics that will be consistent with the desired positive effects on our health and for which the science is conclusive.

References

Jäger, R., Mohr, A. E., Carpenter, K. C., Kerksick, C. M., Purpura, M., Moussa, A., . . . Black, K. (2019). "International Society of Sports Nutrition Position Stand: Probiotics,"Journal of the International Society of Sports Nutrition, vol. 16,^no.1, p. 62.

Landman, C., & Quévrain, E. (2016). "The gut microbiota: description, role, and pathophysiological implications,"La Revue de médecine interne, vol. 37,^no.6, pp. 418-423.

Mika, A., & Fleshner, M. (2016). "Early-life exercise may promote lasting brain and metabolic health through gut bacterial metabolites,"Immunology and Cell Biology, vol. 94,^no.2, pp. 151-157.

Salehzadeh, K. (2015). "The effects of probiotic yogurt drink on lipid profile, CRP and record changes in aerobic athletes,"International Journal of Life Sciences, vol. 9,^no.4, pp. 32-37.