Gender Difference in the Impact of Total Energy Intake on the Association between Low Fiber Intake and Mental Health in Middle-Aged and Older Adults.

The effect of dietary fiber intake on mental health is controversial. This study aimed to examine the association of fiber intake with mental health in Korean adults. This cross-sectional study included 11,288 participants aged ≥40 years who participated in the Korean Genome and Epidemiology Study (2004-2013). Fiber intake was assessed using a food frequency questionnaire and categorized into sex-specific quintiles. Multiple logistic regression models were used to investigate the association between the lowest quintile of fiber intake and poor mental health. Mental health was assessed using acute stress perception, the Psychosocial Well-Being Index-Short Form, self-rated health, and the Center for Epidemiological Studies-Depression Scale in Korea. Compared to those with higher fiber intake, having the lowest quintile of fiber intake was associated with higher odds of poor mental health risk, a higher risk of high-stress perception, poor psychosocial distress in males, poor psychosocial distress, and depression in females. Low fiber intake had profound negative mental health effects on males with high total energy intake and females with low total energy intake. In conclusion, there is a gender difference in the impact of total energy intake on the deleterious effect of low fiber intake on mental health.