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

AIM: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.