Higher dietary glycemic index, but not glycemic load, is associated with a lower prevalence of depressive symptoms in a cross-sectional study of young and middle-aged Japanese women.

OBJECTIVE

Epidemiologic evidence on the associations between dietary glycemic index (GI) and glycemic load (GL) and depressive symptoms is not only limited, particularly in Asian populations where dietary GI and GL are typically higher than in Western countries, but also inconclusive. This cross-sectional study examined these associations in Japanese women.

METHODS

Subjects were 3963 young (age 18-years) and 3826 middle-aged (mean age 47.8 years) Japanese women. Dietary GI and GL were assessed using a validated diet history questionnaire. Depression symptoms were defined as present when subjects had a Center for Epidemiologic Studies Depression score ≥16.

RESULTS

The prevalence of depressive symptoms was 50.2% for young women and 27.3% for middle-aged women. The mean (SD) values of energy-adjusted dietary GI and GL (GI for glucose = 100) were, respectively, 64.9 (4.3) and 142.0 (27.4) for young women and 65.0 (4.1) and 142.2 (29.5) for middle-aged women. After adjustment for potential confounding factors, higher dietary GI was associated with a lower prevalence of depressive symptoms. Adjusted OR (95% CI) for depressive symptoms in the highest compared to lowest quintiles of dietary GI was 0.66 (0.52, 0.82) for young women (P for trend = 0.001) and 0.75 (0.60, 0.96) for middle-aged women (P for trend = 0.046). Conversely, there was no association between dietary GL and depressive symptoms in either age group.

CONCLUSIONS

Dietary GI, but not GL, was inversely associated with depressive symptoms in a group of young and middle-aged Japanese women with relatively high dietary GI and GL.