Gut Microbiome and Metabolome Variations in Self-Identified Muscle Builders Who Report Using Protein Supplements.

Lauri O Byerley,Kristin S Ondrak,Shawn R Campagna,Karyn M Gallivan,Gregory M Davis,Scot E Dowd,Christopher M Taylor,Courtney J Christopher,Hector F Castro,Meng Luo

doi:10.3390/nu14030533

Abstract

Muscle builders frequently consume protein supplements, but little is known about their effect on the gut microbiota. This study compared the gut microbiome and metabolome of self-identified muscle builders who did or did not report consuming a protein supplement. Twenty-two participants (14 males and 8 females) consumed a protein supplement (PS), and seventeen participants (12 males and 5 females) did not (No PS). Participants provided a fecal sample and completed a 24-h food recall (ASA24). The PS group consumed significantly more protein (118 ± 12 g No PS vs. 169 ± 18 g PS, p = 0.02). Fecal metabolome and microbiome were analyzed by using untargeted metabolomics and 16S rRNA gene sequencing, respectively. Metabolomic analysis identified distinct metabolic profiles driven by allantoin (VIP score = 2.85, PS 2.3-fold higher), a catabolic product of uric acid. High-protein diets contain large quantities of purines, which gut microbes degrade to uric acid and then allantoin. The bacteria order Lactobacillales was higher in the PS group (22.6 ± 49 No PS vs. 136.5 ± 38.1, PS (p = 0.007)), and this bacteria family facilitates purine absorption and uric acid decomposition. Bacterial genes associated with nucleotide metabolism pathways (p < 0.001) were more highly expressed in the No PS group. Both fecal metagenomic and metabolomic analyses revealed that the PS group’s higher protein intake impacted nitrogen metabolism, specifically altering nucleotide degradation.

Highlights

IntroductionA recent review article reported that 40–100% of athletes used some type of supplement, including protein, intending to improve athletic performance [1]
There were no significant differences in age, weight, height, or BMI between the protein supplement (PS) and no protein supplement (No PS) groups
Differences in diet and the gut microbiome and metabolome suggested that protein influenced the gut microbiota

Summary

Introduction

A recent review article reported that 40–100% of athletes used some type of supplement, including protein, intending to improve athletic performance [1]. Most of the protein-supplement products on the market are whey-, casein-, or soy-based, and research has shown that whey, casein, and/or soy protein promote/s similar amounts of protein synthesis and strength gains [2]. In the last few decades, the importance of gut microbiota in promoting health has been recognized. The largest concentration of microbes, including bacteria, archaea, fungus, and viruses, is found in the colon. Food has the biggest impact on shaping the gut microbiome, many other daily activities, such as exercise and sleep, can affect the relative abundance of microbes. A shift in the relative abundance of even the microbes that sparsely populate the gut can be beneficial or harmful to one’s health

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