The researchers from Spain recruited 16 professional cyclists competing in the Vuelta a Espaรฑa, a 3,290.7 kmย Grand Tourย cycling stage race that took place in Spain,ย Andorra, and France from Aug. 24 to Sept. 15 2019.
Based on the assessment of dietary intake and faecal samples throughout the three-week race, the study concluded that changes in gut microbiota composition, which were influenced by carbohydrate (CHO) intake, correlated adversely with performance.
“The composition and periodization of supplementation during a Grand Tour, particularly carbohydrates, could be designed to modulate gut microbiota composition to allow better performance,” the researchers wrote in the journalย Nutrientsโ.
“Future strategies to enhance the performance of high-level athletes could include the selective growth of specific targeted bacterial taxa usingย ร la carteโย prebiotics instead of the current ineffective probiotic supplementation, which usually cannot maintain stable populations in the gut ecosystem.”
Athletes’ gut healthโ
Grand tours involve repeated and continuous days of competition,ย entailing extreme physiological and metabolic demandsโย and responses, components of exercise that have been identified as factors that canย modify the diversityโย and abundance of certain bacterial groups.
Research suggests that gut microbiota composition and metabolic activityย directly influence physical performanceโ, and there is an increasing interest in the potential of sports supplements to enhance performance byย modulating gut microbiota compositionโย and metabolic activity.
Depletion of energy is a common limiting factor during exercise, which is often targetted through carb loading where athletes will maximize their glycogen stores before endurance events by increasing CHO intake through both food and supplements.ย However,ย there is evidenceโย that simple CHO intake may adversely impact the gut microbiota and, in turn, sports performance.ย
Theย effects of various supplementsโย (probiotics, prebiotics, proteins, antioxidants, branched-chain amino acids, caffeine, etc.) on gut microbiota are well established, but the researchers noted thatย more informations is needed on how exercise, especially in high-level athletes during competition, affects gut microbiota composition, which makes supplementation “imprecise and potentially ineffective”.
.Supplementing during racesโ
During the race, faecal samples were collected at four time points: the day before the first stage (A); after 9 stages (B); after 15 stages (C); and on the last stage (D). Faecal microbiota populations and SCFA content were analysed using 16S rRNA sequencing and gas chromatography, respectively, and dietary intake recordedย using a validated food frequency questionnaire.
The consumption of high-CHO sports supplements increased significantly during competition (CHO drinks: 442 ยฑ 677%; gels: 533 ยฑ 47%; energy bars: 288 ยฑ 214%; sport snacks: 167 ยฑ 145%).
The athletes also consumed probiotic supplements daily during the competition, including combinations of the speciesย Bifidobacterium lactisโ,ย Bifodobacterium bifidumโ,ย Lactobacillus paracaseiโย andย Lactobacillus acidophilus.โ
Data analyses were carried out to explore the dynamics of microbiota and SCFAs and their relationship with performance.
Findings indicated thatย Bifidobacteriaceaeโ,ย Coriobacteriaceaeโ,ย Erysipelotrichaceaeโย andย Sutterellaceaeโย presence correlated with strong final performance.
Cyclists with a lower frequency of consumption of CHO-rich supplements (CHO drinks, gels, and sports snacks, taken together) showed a tendency towards a higher relative abundance of the familyย Bifidobacteriaceae.โ
While consumption of high-CHO sports supplements increased significantly in all participants during competition, the cyclists with the lower increase in their CHO consumption showed a tendency towards a higher abundance ofย Bifidobacteriaceae,ย โwhichย โwas related to a lower accumulated time at the end of La Vuelta and therefore, better performance.
Additionally, the researchers found that they were “unable to detect any of the strains included in the probiotic supplements or in the probiotic foods used”.
“Although the cyclists were taking probiotic supplements containing bifidobacteriaย during competition, the relationship between bifidobacteriaย abundance and performance appears to be modulated by diet in a way that is apparently more relevant to performance than the use of probiotic supplements,โ they concluded.
โFurther research into the composition of the intestinal microbiota and the products of its metabolic activity will help understand its potential modulatory role in the response to exercise and to optimize and personalize the use of supplements.โ
Journal:ย Nutrientsโ
doi:ย 10.3390/nu16050661โ
โDynamics of Gut Microbiota and Short-Chain Fatty Acids during a Cycling Grand Tour Are Related to Exercise Performance and Modulated by Dietary Intake.โ
Authors: Manuela Fernandez-Sanjurjo et al.