Is the future of personalized sports nutrition to be found in the microbiota?
Top-level athletes are always on the lookout for ways to improve performance. A new science-based approach hopes to optimize their times by “feeding” their gut microbiota.
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Do athletes have a specific microbiota?
A number of studies have looked closely at the microbiota of top-level athletes in an attempt to identify any specific characteristics, or even the bacteria associated with their performance. Generally speaking,
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Athlete
A competitive sportsman or sportswoman who strives for a high level of performance through training.
Source: Rousseau AS. Nutrition, santé et performance du sportif d’endurance / Nutrition, health and performance of endurance athletes. Cahiers de Nutrition et Diététique. 2022 eb ;57(1) : 78-94
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' flora does indeed seem different.
First of all, the gut microbiota of athletes is more diverse. The athletes’ cardiorespiratory fitness, and more specifically their maximum oxygen consumption ( (sidenote: VO2max A criterion specific to each athlete, VO2max is the maximum quantity of oxygen that the body can extract from the air and transport to the muscle fibers to meet their needs during exercise. The higher the VO2max, the better the performance. When this criterion is low, sporting ability is limited, and specific training will be needed to boost it. ) ), seems to be linked to the diversity of their gut microbiota. 2
The gut microbiota
Secondly, the microbiota of athletes is richer in beneficial bacteria (Bifidobacterium, Lactobacilli, and Akkermansia) and produces more valuable short-chain fatty acids ( (sidenote: Short chain fatty acids (SCFA) Short chain fatty acids (SCFA) are a source of energy (fuel) for an individual’s cells. They interact with the immune system and are involved in communication between the intestine and the brain. Silva YP, Bernardi A, Frozza RL. The Role of Short-Chain Fatty Acids From Gut Microbiota in Gut-Brain Communication. Front Endocrinol (Lausanne). 2020;11:25. ) ) 3,4. However, there are major differences based on the sport and the athlete. For example, in the microbiota of the aforementioned rugby players, several bacterial taxa are over-represented, starting with Akkermansiaceae. 1 In marathon runners and cross-country skiers, the gut flora is richer in bacteria from the large Firmicutes family (which includes “good bacteria” lactobacilli) and less rich in Bacteroidetes. The result is a favorable ratio between these two bacterial families (F/B ratio) associated with a higher VO2max, a key factor in performance. 5
The Firmicutes and Bacteroidetes bacterial groups together account for 70% to 90% of our gut bacterial community. 8, 9
Prevotella, bacteria associated with better physical performance, are also over-represented in marathon runners. 5 The same was true of professional cyclists in the US: Prevotella abundance increased with the number of hours they trained per week. 2
However, the big question that remains is whether athletes’ specific microbiota is the cause of their extraordinary performance or the consequence of their intense sporting activities, combined with a very specific diet. The answer is probably a virtuous circle involving a bit of both.
Is modulating the gut microbiota an ideal strategy for improving athletes’ health and performance?
A direct consequence of the relationship between the gut microbiota and sporting performance is the temptation for athletes to optimize their gut flora, whether through diet (to nourish their bacteria) or probiotics. 6
On the dietary side, research is beginning to take up the subject, focusing in particular on the benefits of a high-fiber diet for athletes’ microbiota and digestive health. 3 After all, athletes tend to opt for pasta over lentils and salad. However, their fiber intake should be proportional to their high caloric intake: 14 g of fiber per 1,000 kcal per day should help promote gastrointestinal health and performance. Furthermore, fiber intake should be avoided just before or after exercise, to avoid adding the effects of fiber (bloating, accelerated transit) to an already strained digestive system. 3
As for probiotics, the wide range of strains, doses, sports, and athletes makes it difficult to reach any conclusions. 3 Nevertheless, scientific studies have reported beneficial effects on general health, particularly immunity. In female swimmers, a probiotic yoghurt containing Lactobacillus acidophilus spp., Lactobacillus delbrueckii bulgaricus, Bifidobacterium bifidum, and Streptococcus salivarus thermophilus limits episodes of respiratory infection after competition. In rugby players, a probiotic containing several strains also reduces the frequency of upper respiratory tract disorders and gastrointestinal symptoms. Other studies show an improvement in immune function. 6
In terms of performance, certain experiments on mice seem promising. The most striking example is the bacterium Veillonella atypica, associated with the performance of marathon runners, which transforms a waste product of their muscles (lactate) into fuel (propionate).
By simply adding this bacterium to the digestive tract of mice, they become the new stars of the treadmill. 7 On the other hand, mice fed a diet devoid of fibers that are fermentable by bacteria drag themselves along the treadmill, losing muscle masse. 4 However, these results in rodents are preliminary and must be confirmed by studies on humans.
