Research

Mixed

Consumption of protein supplements by muscle builders significantly alters gut microbiome composition and fecal metabolome, specifically increasing the abundance of Lactobacillales and allantoin while decreasing nucleotide metabolism gene expression compared to non-supplement users.

If you use protein supplements, your gut bacteria and metabolites will look different than non-users, specifically with higher levels of Lactobacillales and allantoin. This is a normal adaptation to higher protein/purine intake and does not imply negative health effects in this population.

ModerateSupportsMEDIUM confidence
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... Metabolomic analysis identified distinct metabolic profiles driven by allantoin (VIP score = 2.85, PS 2.3-fold higher)... Bacterial genes associated with nucleotide metabolism pathways (p < 0.001) were more highly expressed in the No PS group.
Lauri O. Byerley et al. · Nutrients · 2022

Why this rating

Cross-sectional observational study with a small sample size (n=39) and self-reported supplement usage; establishes association, not causation.

Source

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

Lauri O. Byerley et al. · Nutrients · 2022

DOI 10.3390/nu14030533

cross_sectional · n=39Cited 8×
Read the paper
DOI resolved against Crossref · corpus check 2026-06-10

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