Daily intake of live microbes and cognitive function in older adults: the mediating role of mitochondrial dysfunction

This study analysed the NHANES (2010-2014) data of 2,312 elderly people to investigate the relationship between dietary intake of live microbes (DLM) and cognitive function and the mediating role of mitochondrial dysfunction between them. Linear regression indicated that the high-DLM group was positively associated with z-score of Digit Symbol Substitution Test (DSST) (β = 0.13, p < 0.05) and global cognitive score (β = 0.37, p < 0.05). Logistic regression showed that high-DLM was a protective factor for cognitive impairment among the elderly (OR = 0.62, p < 0.05). Mediation analysis revealed that circulating methylmalonic acid (MMA) was negatively associated with high-DLM (β = −22.98, p < 0.05) and it exerted a mediating effect on the relationship between the high-DLM group and DSST and global cognitive score, with the mediated proportions of 3.8%, and 4.1%, respectively. Moreover, high-DLM is associated with better cognitive function through its relationship with MMA in older adults.