Depression, a mental disorder associated with decreased productivity, poor psychosocial outcomes, and decreased quality of life, is a significant public health problem affecting millions of people in the US and elsewhere. Epidemiological studies have examined the association of low zinc (Zn) status with depression, but clinical trials on the effect of Zn supplementation in depression are limited. Researchers from Australia and Poland conducted a review of randomized controlled trials with a comparison group that examined Zn supplementation as the intervention, and depressive symptoms as the primary outcome. Four randomized controlled trials met inclusion criteria. In studies that examined the effects of Zn supplementations as an adjunct to antidepressants, Zn (7 to 25 mg/day for 10-12 wks) significantly lowered depressive symptom scores of depressed patients. In addition to depressive symptoms, researchers also examined the effect of Zn on other mood states such as anger, anxiety and tension. Results showed improvement in all mood states with Zn supplementation. Researchers concluded that the evidence suggests significant benefits from Zn supplementation, as a stand-alone intervention or as an adjunct to conventional drug therapy for reducing depressive symptoms in clinically depressed patients.
J Lai, et al. The efficacy of zinc supplementation in depression: Systematic review of randomized controlled trials. J of Affective Disorders 136 (2012) e31-e39