Dietary manganese helps fight diabetes in women

High manganese intake from foods and drinks lowers the risk of developing type 2 diabetes in women but not in men, a study has found.

The analysis was based on 19,862 Japanese men and women in the Japan Collaborative Cohort Study. All participants completed a food frequency questionnaire at the baseline survey. Men and women in higher vs lowest intake quartiles of manganese tend to walk for at least 1 hour per day, were less likely to have high mental stress, and drank coffee daily. They also were more likely to have greater intakes of vitamins, minerals, dietary fibre, and total energy.

Over a 5-year period, 530 participants developed type 2 diabetes (263 men and 267 women). This corresponded to a 5-year cumulative incidence of 2.7 percent (3.6 percent in men and 2.1 percent in women).

Higher manganese intake was protective against the cumulative risk of incident type 2 diabetes in women but not in men. In a fully adjusted logistic regression model, the odds ratios (ORs) associated with quartiles 2–4 versus 1 of manganese intake (Q1 to Q4) were 0.74 (95 percent confidence interval [CI], 0.51–1.06), 0.62 (95 percent CI, 0.41–0.94), and 0.53 (95 percent CI, 0.31–0.88; p_trend=0.01) among women.

The respective OR estimates in men were 0.97 (95 percent CI, 0.65–1.43), 1.04 (95 percent CI, 0.67–1.61), and 1.10 (95 percent CI, 0.64–1.92; p_trend=0.66).

The association between dietary manganese and diabetes risk was pronounced among women with low iron intake, especially premenopausal women, and independent of other dietary intakes and diabetes risk factors.