Relation Between Dietary Protein Intake and Gut Microbiome Composition in Community-Dwelling Older Men: Findings from the Osteoporotic Fractures in Men Study (MrOS)

Background Little is known about the association of specific nutrients, especially proteins, on age-related gut dysbiosis. Objectives To determine the associations between the quantity and sources (vegetable and animal) of dietary protein intake and gut microbiome composition in community-dwelling older men. Methods We performed a cross-sectional analysis on 775 older men from the Osteoporotic Fractures in Men Study (MrOS) (age 84.2 +/- 4.0 y) with available dietary information and stool samples at visit 4 (2014-2016). Protein intake was estimated from a brief FFQ and adjusted to total energy intake. The gut microbiome composition was determined by 16S (v4) sequencing (processed by DADA2 and SILVA). A total of 11,534 amplicon sequence variants (ASVs) were identified and assigned to 21 phyla with dominance of Firmicutes (45%) and Bacteroidetes (43%). We performed alpha-diversity, beta-diversity, and taxa abundance (by Analysis of Compositions of Microbiomes with Bias Correction [ANCOM-BC]) to determine the associations between protein intake and the gut microbiome. Results Median protein intake was 0.7 g/(kg body weight center dot d). Participants with higher energy-adjusted protein intakes had higher Shannon and Chao1 alpha-diversity indices (P < 0.05). For beta-diversity analysis, participants with higher protein intakes had a different center in weighted and unweighted UniFrac Principal Co-ordinates Analysis (PCoA) compared with those with lower intake (P < 0.05), adjusted for age, race, education, clinical center, batch number, fiber and energy intake, weight, height, and medications. Similarly, higher protein consumptions from either animal or vegetable sources were associated with higher gut microbiome diversity. Several genus-level ASVs, including Christensenellaceae, Veillonella, Haemophilus, and Klebsiella were more abundant in participants with higher protein intakes, whereas Clostridiales bacterium DTU089 and Desulfovibrio were more abundant in participants with lower protein intake (Bonferroni corrected P < 0.05). Conclusions We observed significant associations between protein intake and gut microbiome diversity in community-living older men. Further studies are needed to elucidate the mediation role of the gut microbiome on the relation between protein intake and health outcomes in older adults.

Automated summary

The study found significant associations between dietary protein intake and gut microbiome diversity in community-dwelling older men. Different sources of protein intake also had varying effects on gut microbiome composition. Further research is needed to explore the role of gut microbiome in mediating the relationship between protein intake and health outcomes in older adults.