Gut Microbiota Signatures of Sarcopenia: A Comparative 16S rRNA Sequencing Study in Older Indian Adults

Emerging evidence suggests that alterations in gut microbiota composition may contribute to the onset and progression of sarcopenia through mechanisms involving systemic inflammation, metabolic dysregulation, and reduced production of short-chain fatty acids (SCFAs). However, data from Indian older adults-who exhibit diverse diets and microbiota profiles-are lacking.

This hospital-based cross-sectional pilot study enrolled 30 older adults aged ≥ 60 years, including 15 with sarcopenic and 15 age- and sex-matched nonsarcopenic. Sarcopenia was classified according to the Asian Working Group for Sarcopenia (AWGS-2019) criteria. Stool samples were analyzed using 16S ribosomal RNA (rRNA) sequencing (V3-V4 region, Illumina MiSeq). Taxonomic classification and diversity indices (Chao1, Shannon, UniFrac) were compared between groups.

The mean age (S.D.) of study participants was 73.27 ± 5.96 years. A total of 251 315 high-quality sequences were generated from 30 fresh human fecal samples. The dominant phylum in the nonsarcopenic group was Firmicutes (41.2%), followed by Bacteroidetes (36.0%), whereas in the sarcopenic group, Bacteroidetes (39.2%) was most common, followed by Firmicutes (37.8%). A decrease in Operational Taxonomic Units (OTUs) of genus Bifidobacterium (2.21% vs. 3.71%), Bacteroides (8.50% vs. 11.11%) was observed in the sarcopenic group. An increase in OTUs of genus Faecalibacterium (10.64% vs. 8.23%) in the sarcopenic group was observed. The alpha-diversity index Chao1, Shannon was reduced in sarcopenic population.

Exploratory differences in microbial diversity and relative abundance were observed between sarcopenic and nonsarcopenic older adults. These findings are descriptive and hypothesis-generating and warrant confirmation in larger, adequately powered studies.