Physical Activity Is Associated With Reduced Mild Depression and Altered Gut Microbiota in Japanese Adult Women

Although there is much evidence for the influence of physical activity on mental illness, there is a lack of analysis of the relationship between physical activity and depression via gut microbiota. This study aimed to examine whether physical activity is associated with reduced mild depression and altered gut microbiota composition in Japanese adult women.

The participants answered the International Physical Activity Questionnaire (IPAQ) to assess physical activity and the Beck Depression Inventory-II (BDI-II) to assess symptoms of depression. The inclusion criteria were as follows: age 50 to 80 years, non-smokers, and not taking antibiotics at the time of study entry. The items measured were the gut microbiota, dietary questionnaire (Brief-Type Self-Administered Diet History Questionnaire (BDHQ)), body weight, body fat percentage, blood pressure, and blood test results (glucose, HbA1c, triglyceride, high-density lipoprotein (HDL)-cholesterol, and low-density lipoprotein (LDL)-cholesterol). Comparison of means between groups was analyzed using a two-way analysis of variance (ANOVA), and then, the Dunn test was conducted as a post hoc test.

Alpha- and beta-diversities showed no significant differences among all groups. In the comparison between the Dep (-) group and the Dep (+) group, six bacteria were identified, whereas in the comparison between the Sed group and the Act group, five bacteria were extracted (p < 0.05). In particular, Megamonas showed a positive correlation with triglycerides and HbA1c, and Holdemania, which acts to suppress depression, was common in the Act and Dep (-) groups.

Our findings support the concept that physical activity influences brain functions in women with mild depression via the gut microbiota. This suggests that promoting physical activity that induces changes in the gut microbiota may be a protective approach to depression in women.