Dietary intake of folate, other B vitamins, and ω-3 polyunsaturated fatty acids in relation to depressive symptoms in Japanese adults

Objective Although a favorable effect of dietary folate and ω-3 polyunsaturated fatty acids (PUFAs) on depression is suggested from epidemiologic studies in Western countries, evidence from non-Western populations is lacking. We examined cross-sectional associations between the intake of folate, other B vitamins, and ω-3 PUFAs and depressive symptoms in Japanese adults. Methods Subjects were 309 Japanese men and 208 Japanese women 21–67 y of age. Dietary intake was assessed with a validated, brief, self-administered diet history questionnaire. Depressive symptoms were defined as present when subjects had a Center for Epidemiologic Studies Depression scale score ≥16. Adjustment was made for age, body mass index, work place, marital status, occupational physical activity, leisure-time physical activity, current smoking, current alcohol drinking, and job stress score. Results The prevalences of depressive symptoms were 36% for men and 37% for women. Folate intake showed a statistically significant, inverse, and linear association with depressive symptoms in men but not in women. The multivariate odds ratios (95% confidence intervals) for depressive symptoms for men in the first, second, third, and fourth quartiles of folate intake were 1.00 (reference), 0.78 (0.38–1.63), 0.57 (0.27–1.18), and 0.50 (0.23–1.06), respectively (P for trend = 0.045). No statistically significant linear association was observed for the intake of riboflavin, pyridoxine, cobalamin, total ω-3 PUFAs, α-linolenic acid, eicosapentaenoic acid, or docosahexaenoic acid in either sex. Conclusion Higher dietary intake of folate was associated with a lower prevalence of depressive symptoms in Japanese men but not women.