Age-related dynamics of methanogens in the human gut: implication of longevity and health

The reciprocal relationship between aging and alterations in the gut microbiota is a subject of ongoing research. While the role of bacteria in the gut microbiome is well-documented, specific changes in the composition of methanogens during extreme aging and the impact of having high methanogen phenotype on health remain unclear. We analyzed metagenomic data from the stool samples of young adults, older adults and centenarians. Our findings reveal that the prevalence of high methanogen phenotype increases with age, while overall archaeal diversity diminishes. Surprisingly, the archaeal composition of methanogens in centenarians' microbiome appears more akin to that of younger adults, showing an increase in M.smithii, rather than Ca. M.intestini. Remarkably, Ca. M.intestini emerged as a central player in the network stability of adults, paving the way for M.smithii in older adults and centenarians. Notably, centenarians exhibit highly complex and stable network of these two methanogens with other bacteria. Furthermore, the mutual exclusion of Lachnospiraceae and these methanogens throughout all age groups suggests that these archaeal communities may compensate for the age-related drop in Lachnospiraceae, potentially with involved in butyrate production pathway with high methanogen phenotype in all three age groups and the positive correlation of these genes with Oscillospiraceae. In conclusion, isturbances in the formation of high methanogen phenotype during aging are critical for maintaining butyrate levels in the gut. This study highlights the dynamic nature of high methanogen phenotype and their impact on gut health throughout aging.