Increased intake of plant protein is associated with changes in composition and functionality of the gut microbiome during a period of intense training

This study investigated the effects of dietary supplementation with plant-based (lentil) vs. animal-based (whey and egg) food interventions on gut microbiota composition and faecal short-chain fatty acid, in healthy adults undergoing a 12-week resistance training program. A total of 24 participants (aged 18–35 years; 11 males and 13 females) were recruited and randomly assigned to one of three intervention groups: Placebo (N = 9), Animal Protein (N = 7), or Plant Protein (N = 8). Participants consumed protein-enriched pasta and beverages according to their group allocation. Stool samples were collected at five time points for microbial and SCFA analyses. Gut microbiota composition was assessed through 16S rRNA gene sequencing and SCFA concentrations were quantified via gas chromatography with flame ionization detection (GC-FID), 16S rRNA sequencing revealed enhanced microbial diversity and enrichment of SCFA-producing genera (e.g., Fusicatenibacter, Faecalibacterium, and Agathobacter) in the lentil protein group. Functional prediction highlighted upregulation of microbial pathways associated with carbohydrate metabolism and gut barrier integrity in both the plant and animal protein groups presumably associated with increased exercise. In addition, the plant protein group showed a significant increase in beneficial SCFA-, particularly butyrate and acetate. By integrating microbial composition, functional pathway analysis, and metabolite profiles, the study highlights the potential of plant-based protein to enhance gut microbial diversity and function, particularly through the promotion of beneficial SCFA-producing bacteria. These findings suggest that plant proteins may offer more favorable outcomes for gut health than animal-derived proteins.