Obesity and mental health improvement following nutritional education focusing on gut microbiota composition in Japanese women: a randomised controlled trial.

PURPOSE: Gut microbiota composition was supposedly related to obesity and psychological factors. We examined the effects of a nutritional education intervention focusing on gut microbiota composition on obesity and psychological factors among obese women.

METHODS: Forty-four obese Japanese women aged 40 or older were randomly assigned to either an intervention group (n = 22) or control group (n = 22). The intervention consisted of a 20-min dietary lecture and a 10-min counselling session by registered dieticians, every 2 weeks for eight consecutive weeks. Body weight, height, waist circumference, food frequency, and gut microbiota composition were measured, and self-rated health and psychological factors were scored before and after the intervention.

RESULTS: All participants completed the 8 week program. After the intervention, dietary fibre intake (p < 0.01), frequency of vegetable consumption (p = 0.020), and frequency of milk and milk product consumption (p < 0.01) increased significantly in the intervention group compared with the control group. Body weight and body mass index (BMI; p < 0.001), waist circumference (p < 0.01), and the depression scale score (p < 0.01) decreased significantly, while significant improvements were found in self-rated health (p = 0.045) and microbiome diversity (p < 0.01).

CONCLUSION: Nutritional education focusing on gut microbiota composition may improve obesity and psychological factors in obese women.