A cross-sectional study on the relationship between nutrient/food intake and gut microbiota in frailty among older community residents: The Kyotango study.

In strategies to extend a healthy lifespan, early detection and prevention of frailty are critical. The purpose of this study was to analyze the current state and clinical risk factors of frailty among community-dwelling older to conduct a cross-sectional analysis of the individuals, correlation between frailty and nutrient intake, dietary diversity, and dietary patterns, and to elucidate the correlation between frailty-related dietary factors and the gut microbiota. The study included 786 participants aged ≥65 years from the Kyotango Multipurpose Cohort Study who had available data on their gut microbiota. Frailty was quantitatively assessed by selecting 32 items from the previously reported frailty index, with those scoring ≥0.21 classified as frailty (n = 119) and those with scores <0.21 as non-frailty (n = 667), followed by group comparisons. The frailty group had significantly higher values and rates than the non-frailty group for the following items: age, obesity (in females only), diabetes, hypertension, history of cancer treatment, polypharmacy, disturbed sleep quality, low physical activity, serum insulin levels, and high-sensitivity C-reactive protein. The frailty group had significantly lower levels of nutrients, including plant proteins, potassium (K), magnesium (Mg), iron (Fe), copper (Cu), vitamins B and C, folic acid, and total, soluble, and insoluble dietary fiber. When analyzed by food groups of dietary fiber, the frailty group had significantly lower intakes of soy products and non-green-yellow vegetables, specifically. The Japanese Diet Index score (rJDI12) was significantly lower in the frailty group, with significant deficiencies in soy products and mushrooms included in the rJDI12. Cluster analysis of the Spearman correlation values between nutrient intake related to frailty and the gut microbiota abundance revealed a positive correlation between the cluster containing dietary fiber and the abundance of the phylum Bacillota, including the [Eubacterium]_eligens_group. In conclusion, our findings clarify the current state of frailty among older community residents and suggest the importance of a diverse range of plant-based foods, including soy products and non-green yellow vegetables, through correlation analysis with nutrients and food groups, and partially reveal the involvement of the gut microbiota.