The findings of a review and meta-analysis suggests that zinc supplementation may improve symptoms in patients with clinical depression being treated with antidepressant drugs.
The review sourced randomised, controlled, cross-over trials that evaluated the effect of zinc supplementation vs a comparator for prevention or improvement of depressive symptoms in children, adolescents, or adults.
The initial search identified 12,322 studies, five of which were eligible for meta-analysis. Four studies involved participants with a diagnosis of major depression and one clinical trial included individuals with depressive symptoms. Only the studies that used the Beck Depression Inventory (BDI) scale were included in the meta-analysis.
The standardised mean difference (SMD) showed an average reduction of 0.36 point (95%CI -0.67 to -0.04) with zinc supplementation compared with placebo. In individuals aged ≥ 40 years, the SMD was reduced by 0.61 point (95%CI -1.12 to -0.09) in the intervention group vs the placebo group.
The meta-analysis by sample size did not show an effect of zinc supplementation in reducing depressive symptoms (SMD -0.28; 95%CI, -0.67 to -0.10; and SMD -0.52; 95%CI, -1.10 to 0.06).
The authors conclude that zinc supplementation contributes to a significant reduction in depressive symptoms in individuals with a clinical diagnosis of major depression who are treated with antidepressant therapy.