Maintaining a healthy and varied bacterial flora helps to achieve post-holiday goals such as following a balanced diet or staying in shape
An unstable microbiota can cause more fatigue in the athlete

Prebiotic foods, with fermentable fiber and polyphenols, help maintain the microbial ecosystem in good condition

Madrid, September 08, 2022. After the holidays and some food excesses, September is for many people the ideal time to consider a healthy life. This is when interest grows in balanced diets and physical exercise to return to pre-holiday habits or even improve them. In this race, the intestinal microbiota can be a great ally or a destabilizing factor when it comes to achieving these post-holiday goals.
The microbiota or intestinal flora is a set of microorganisms that live in the intestine. “Maintaining its balance is essential to prevent the colonization of other pathogenic microorganisms, and helps digest food, produce vitamins B and K and stimulate the immune system. If alterations occur, they can affect people’s health and sports performance,” explains Daniel Badia, collaborating professor at the UOC’s Health Sciences Department.

“Imbalances in the microbiota, called dysbiosis, can cause nutritional deficiencies, excessive fermentations and intestinal permeability, among others. All these conditions have a negative influence on the performance of the athlete, either by causing intestinal discomfort, compromising the types of food that must be eaten during physical exercise or causing damage to the energy field, which manifests itself in a feeling of more fatigue» warns Badia, who is a collaborating professor on the UOC’s Master’s Degree in Nutrition in Physical Activity and Sport.
For the expert, the intestinal microbiota can positively influence sports performance through the production of short-chain fatty acids from the fermentation of fiber in the large intestine. These acids can be oxidized in muscle and thus contribute to muscle glucose availability. They also contribute to increased blood flow, insulin sensitivity and the preservation of muscle mass, very interesting issues from the point of view of the health and performance of the athlete.

Foods that benefit the intestinal microbiota

Nutrients that benefit the microbiota, by improving the number, variety, and activity of bacteria that live in the gut, are called prebiotics. The UOC professor explains what properties these types of foods have:
Fermentable fiber. Among the prebiotics, vegetables that contain fermentable fiber are the most important. Although our small intestine cannot digest or absorb this type of fiber, when it reaches the large intestine it undergoes a partial or total fermentation that feeds the intestinal bacteria. “If we want to have a healthy and diverse microbiota, we must feed all microbial species, and this requires a diet in which there is an abundance of plant foods as varied as possible,” he points out. “Often we find that athletes eat an adequate amount of plant-based foods, but with little variety. You have to remember that mushrooms are also a very interesting food group,’ he adds.
Cooking food is also key to getting these beneficial fibers for the intestine. For example, the apple or the carrot must be cooked and not raw. “The baked apple releases certain fibers that might not otherwise be fermented,” he explains. It is also advisable to cook potatoes and sweet potatoes, or other non-vegetable foods such as rice and pasta, and then let them cool, because resistant starch is formed, a great food for intestinal bacteria.
Polyphenols. They are found in foods of plant origin such as quercetin, resveratrol, curcumin or epigallocatechins from green tea. «The fruits of the forest, cocoa, tea (especially green), grapes, olive oil, spices, nuts and, in general, fruits and vegetables, are especially rich in polyphenols», remarks the UOC expert.
Healthy fats and quality protein. A responsible diet with the intestinal flora should be completed with healthy fats (virgin olive oil, avocado, coconut, organic eggs and small fatty fish) and with quality protein (legumes, organic grass-fed meat, organic eggs, small fatty fish, crustaceans and molluscs).
As for fermented foods, consumed on a regular basis, they provide microorganisms, but in much smaller quantities than a commercial probiotic. “Probiotics are foods or supplements that contain live microorganisms intended to maintain or enhance bacteria. They can be especially useful when antibiotics have to be used, to protect the native microbiota. They can also be interesting in certain dysbioses, to compensate for those species that are missing and restore balance. In these cases, you have to follow the advice of a professional, ”explains Badia. There is a wide variety of fermented foods that are probiotics: vegetables (sauerkraut, kimchi, olives, pickles…), dairy (yogurt, kefir), beverages such as kombucha, fermented from soy such as miso, etc. Above all, it is important that they are unpasteurized and not subjected to any cooking process, since the microorganisms would die.

Does physical exercise improve the intestinal microbiota?

Several studies have found that exercise increases the diversity of the microbiota and consequently improves metabolic function and immune responses. When assessing the effect of exercise on the microbiota, it is important for the expert to take into account the type of exercise. “Resistance exercise has a more intense effect than resistance exercise in terms of changing the microbiota,” says Badia. “So we see that the composition of the microbiota adapts to exercise, for example, and promotes the growth of bacterial populations that can metabolize lactate,” he adds.

Exercise affects gastrointestinal physiology. It is known that moderate exercise has a positive effect on the functioning of the gastrointestinal system, while more intense and prolonged efforts can cause intestinal disorders, such as gastrointestinal discomfort, especially when not accompanied by adequate nutrition and rest. “These alterations in physiology can be attenuated by the microbiota. Short-chain fatty acids allow repair and maintenance of intestinal epithelia, and reduce the effect of strenuous exercise”, concludes Badia.

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Rosana Ribera de Gracia