Habitual natto consumption is inversely associated with mild cognitive impairment and depressive symptoms in older Japanese adults: A cross-sectional study.

The association of the consumption of natto, a traditional Japanese fermented food, with mild cognitive impairment (MCI) and depressive symptoms remains poorly understood. We hypothesized that natto consumption may be negatively associated with MCI and depressive symptoms among older Japanese adults. We analyzed 616 individuals aged 65 years and older in the logistic regression model. We adjusted for age, sex, living alone, educational level, medication history, physical frailty, dietary diversity, tofu/atsuage (fried tofu) consumption habits, and miso soup consumption habits. The logistic regression analysis showed that natto consumption habits were negatively associated with MCI, even after adjustment (odds ratio [OR]: 0.63; p = .025). Natto consumption habits were also negatively associated with depressive symptoms (OR: 0.63; p = .037). Our findings indicate that natto consumption may be a simple and sustainable approach for maintaining cognitive function and mental health.