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Effect of a Protein Supplement on the Gut Microbiota of Endurance Athletes: A Randomized, Controlled, Double-Blind Pilot Study

Moreno-Pérez, Diego; Bressa, Carlo; Bailén, María; Hamed-Bousdar, Safa; Naclerio, Fernando; Carmona, Manuel; Pérez, Margarita; González-Soltero, Rocío; Montalvo-Lominchar, Maria Gregoria; Carabaña, Claudia; Larrosa, Mar

Date Published:





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March 10, 2018


PMID: 29534465 PMCID: PMC5872755


Nutritional supplements are popular among athletes to improve performance and physical recovery. Protein supplements fulfill this function by improving performance and increasing muscle mass; however, their effect on other organs or systems is less well known. Diet alterations can induce gut microbiota imbalance, with beneficial or deleterious consequences for the host. To test this, we performed a randomized pilot study in cross-country runners whose diets were complemented with a protein supplement (whey isolate and beef hydrolysate) (n = 12) or maltodextrin (control) (n = 12) for 10 weeks. Microbiota, water content, pH, ammonia, and short-chain fatty acids (SCFAs) were analyzed in fecal samples, whereas malondialdehyde levels (oxidative stress marker) were determined in plasma and urine. Fecal pH, water content, ammonia, and SCFA concentrations did not change, indicating that protein supplementation did not increase the presence of these fermentation-derived metabolites. Similarly, it had no impact on plasma or urine malondialdehyde levels; however, it increased the abundance of the Bacteroidetes phylum and decreased the presence of health-related taxa including Roseburia, Blautia, and Bifidobacterium longum. Thus, long-term protein supplementation may have a negative impact on gut microbiota. Further research is needed to establish the impact of protein supplements on gut microbiota.

Automatic Tags

Humans; Male; Adult; Double-Blind Method; Pilot Projects; Physical Endurance; Dietary Supplements; Biomarkers; Sports Nutritional Physiological Phenomena; Gastrointestinal Microbiome; Dietary Proteins; Cattle; Dysbiosis; Feces; Protein Hydrolysates; Spain; Whey Proteins; Bacteroidetes; Bifidobacterium longum; branched short-chain fatty acids; Clostridiales; fecal ammonia; fecal pH; Molecular Typing; Physical Conditioning, Human; sport supplements

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