The human microbiome plays a key role in maintaining host homeostasis and is influenced by age, geography, diet, and other factors. traditionally, india has an established convention of extended family arrangements wherein three or more generations, bound by genetic relatedness, stay in the same household. in the present study, we have utilized this unique family arrangement to understand the association of age with the microbiome. We characterized stool, oral and skin microbiome of 54 healthy individuals from six joint families by 16S rRNA gene-based metagenomics. In total, 69 (1.03%), 293 (2.68%) and 190 (8.66%) differentially abundant OTUs were detected across three generations in the gut, skin and oral microbiome, respectively. Age-associated changes in the gut and oral microbiome of patrilineal families showed positive correlations in the abundance of phyla proteobacteria and fusobacteria, respectively. Genera Treponema and Fusobacterium showed a positive correlation with age while Granulicatella and Streptococcus showed a negative correlation with age in the oral microbiome. Members of genus Prevotella illustrated high abundance and prevalence as a core otUs in the gut and oral microbiome. in conclusion, this study highlights that precise and perceptible association of age with microbiome can be drawn when other causal factors are kept constant.

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The gut microbial community is known to influence the human health and disease state and is shaped by various factors since birth. It is now evident that understanding the alterations in these commensal microbes during crucial stages of life is of utmost importance to determine and predict the health status of an individual. To study the gut microbiota in two such vital stages, pregnancy and infancy, we analyzed gut microbial communities from 20 mother-infant dyads at different stages of pregnancy and early infancy. In total, we analyzed 80 fecal samples for profiling the gut microbial community using 16S rRNA gene-based sequencing. We observed no significant alterations in the gut bacterial diversity during pregnancy; however, significant alterations were observed during the period from birth to six months in infants, with a reduction in Staphylococcus and Enterococcus and an increase in Bifidobacterium and Streptococcus with a more stable microbial community at the age of six months.

Neuropsychiatric diseases and obesity are major components of morbidity and health care costs, with genetic, lifestyle, and gut microbiome factors linked to their etiology. Dietary and weight-loss interventions can help improve mental health, but there is conflicting evidence regarding their efficacy; and moreover, there is substantial interindividual heterogeneity that needs to be understood. We aimed to identify genetic and gut microbiome factors that explain interindividual differences in mental health improvement after a dietary and lifestyle intervention for weight loss. We recruited 369 individuals participating in Digbi Health’s personalized digital therapeutics care program and evaluated the association of 23 genetic scores, the abundance of 178 gut microbial genera, and 42 bacterial pathways with mental health. We studied the presence/absence of anxiety or depression, or sleep problems at baseline and improvement on anxiety, depression, and insomnia after losing at least 2% body weight. Participants lost on average 5.4% body weight and >95% reported improving mental health symptom intensity. There were statistically significant correlations between: (a) genetic scores with anxiety or depression at baseline, gut microbial functions with sleep problems at baseline, and (b) genetic scores and gut microbial taxa and functions with anxiety, depression, and insomnia improvement. Our results are concordant with previous findings, including the association between anxiety or depression at baseline with genetic scores for alcohol use disorder and major depressive disorder. As well, our results uncovered new associations in line with previous epidemiological literature. As evident from previous literature, we also observed associations of gut microbial signatures with mental health including short-chain fatty acids and bacterial neurotoxic metabolites specifically with depression. Our results also show that microbiome and genetic factors explain self-reported mental health status and improvement better than demographic variables independently. The genetic and microbiome factors identified in this study provide the basis for designing and personalizing dietary interventions to improve mental health.