Low dietary or supplemental zinc is associated with depression symptoms among women, but not men, in a population-based epidemiological survey

Abstract

Prior studies indicate that the biochemical alterations of depressive episodes result in decreased serum zinc concentrations. Given these findings, it is plausible that consistently low dietary zinc intakes contribute to depressive symptoms, yet epidemiological data are lacking. The authors tested the hypothesis that low zinc intake is associated with depressive symptoms using cross-sectional data from the population-based Boston Area Community Health survey (2002-2005). Dietary and supplement use data were collected by validated food frequency questionnaire. Current depressive symptoms were assessed by the abridged validated Center for Epidemiologic Studies Depression scale and analyzed using multivariate logistic regression, adjusting for sociodemographic, health and lifestyle characteristics. Results showed an interaction (P=0.03) with gender, whereby zinc was associated with depressive symptoms in women (N=2163), but not men (N=1545). Women with low dietary or supplemental zinc intake were more likely to have depressive symptoms (e.g., dietary zinc quartile 1 vs. 4, OR=1.76, 95% CI: 1.26, 2.45; P-trend=0.004; supplemental zinc P-trend=0.03). Associations were stronger among women using antidepressant medications (e.g., total zinc OR=4.75, 95% CI: 1.98, 11.4; P-trend=0.0005). The cross-sectional, observational nature of the study leaves uncertain whether the observed associations represent actual causal relationships between zinc intake and depressive symptoms. These findings suggest: (1) gender-specific pathophysiological mechanisms of depression, (2) inadequate dietary zinc intake contributes to depressive symptoms in women, and (3) supplemental zinc is a beneficial adjunct to antidepressant therapy in women. Additional research on both men and women is needed to verify these novel findings. If confirmed by other studies, the potential importance of adequate zinc intake is underscored by the recognized limitations of pharmacotherapy for depression.