Green Tea Consumption and Depressive Symptoms among Japanese Workers: The Furukawa Nutrition and Health Study

Although several cross-sectional studies have described an inverse association between green tea consumption and depressive symptoms, only one study has prospectively investigated this association. We investigated the cross-sectional and prospective associations between green tea consumption and depressive symptoms in a working population in Japan. Participants were 1987 workers who participated in the baseline survey for a cross-sectional association, and 916 participants who did not have depressive symptoms at baseline who responded to both the baseline and follow-up surveys for a prospective association. Green tea consumption was evaluated with a validated self-administered diet history questionnaire. Depression symptoms were evaluated with the Center for Epidemiologic Studies Depression (CES-D) scale. Multiple logistic regression was conducted to estimate the odds ratio of depressive symptoms based on green tea consumption. In the cross-sectional analysis, green tea consumption was not associated with the prevalence of depression symptoms. Moreover, consumption at baseline was not associated with depression symptoms after 3 years; the multivariable-adjusted odds ratio of depressive symptoms for >= 2 cups/day of green tea was 1.12 (95% confidence interval 0.65-1.91) compared with <4 cups/week after adjustment for covariates including dietary factors (trend p = 0.67). Our results suggest that there is no association of consumption of green tea with symptoms of depression in Japanese.

Automated summary

This study investigated the association between green tea consumption and depressive symptoms in a working population in Japan. The results suggest that there is no significant association between green tea consumption and symptoms of depression in Japanese individuals.