Abstract
Many studies have focused on ageing and gut microbiota, but the correlation between gut microbiota and physical function in older adults, especially those with longevity, remains obscure and deserves further exploration. In this study we investigated changes in the gut microbiota and the association between gut microbiota and physical function in adults with longevity. This is a prospective observational study. Fifty-one older adults aged ≥ 60 years (including 27 participants aged 90 years and above) were enrolled. Information on clinical data, physical function including intrinsic capacity by Integrated Care for Older People (ICOPE) tool, and dietary habits of participants was collected and analysed. Gut microbiota structure and functional pathways were analysed by Metagenomics. Intrinsic capacity (measured as ICOPE scores) of adults' longevity (aged 90-98, longe group) was significantly lower than older adults aged 60-89 years (CON group) (5.44 ± 2.15 vs. 6.71 ± 1.46, p = 0.017). Gut microbiota of the longe group is enriched in Akkermansia and Bifidobacterium, which may be beneficial to health. Gut microbiota was closely related to daily milk (including plain milk, flavoured milk with a content of cow's milk or reconstituted milk of ≥80%, or reconstituted milk or fermented milk with a content of cow's milk or milk powder of ≥80%) consumption, anxiety, and physical function including grip strength by the Short Physical Performance Battery (SPPB). Bacteroides plebeius and Bacteroides eggerthii were increased in long-living adults with better physical function. Escherichia coli was more abundant in frail young-old adults. Grip strength is positively correlated with the abundance of Roseburia hominis, Eubacterium rectale, Eubacterium eligens, and Roseburia intestinalis (p < 0.05). Pathways related to amino acid synthesis that include L-isoleucine, L-valine, and L-threonine were over-presented in long-living adults of better physical function. Adults with longevity showed comparable gut microbiota abundance to younger elderly individuals. The gut microbiota of long-living adults showed higher abundance of potentially beneficial bacteria, and the altered bacteria are closely associated with physical function. Changes in the gut microbiota may precede clinical indicators during the process of ageing. Gut microbiota may be a potential biomarker for longevity and healthy ageing. Nutrition and emotional state can be important influencing factors.