In several animal studies, zinc deficiency can cause behavior that looks like depression. In other animal studies, giving zinc can have antidepressant-like activity if the animals are zinc-deficient.
And there is some clinical evidence that zinc might boost the effectiveness of antidepressants in humans.
Now a large meta-analysis of studies that looked at zinc blood levels in people with depression (Swardfager, et al) finds that depressed individuals have significantly lower zinc concentrations in their blood.
The authors summarized 17 studies, with a total of 1643 depressed patients and 804 controls studied, in which blood zinc concentrations were measured. In those studies, on average, zinc concentrations were 1.85 μmol/L lower (P < .00001) in depressed subjects than in controls.
The study result is strengthened because the study also found that depression severity was inversely correlated with zinc levels. In other words, the greater the deficiency the more severe the depression.
The finding that zinc levels are associated with depression does not mean that lower zinc causes depression, but there are some interesting aspects of zinc’s role in the body that make the link at least plausible.
Zinc is an anti-oxidant, it helps support the endocrine (hormone) system and the functioning of the immune system. It is involved in regulating brain circuits in the hippocampus (which controls memory) and the cortex (thinking) that use the neurotransmitter glutamate. These circuits are involved in regulating mood.
and immune function, and participates in regulation of
It is possible that normal zinc levels are necessary for normal mood functioning, and that lower zinc levels might lead to depression.
It turns out that zinc is also one of a handful of nutrients that a significant number of people are deficient in.
The Food and Nutrition Board of the Institute of Medicine and the World Health Organization (WHO) have published standard recommendations for daily zinc intake. They recommend that women get 8 mg daily and men receive 11 mg a day.
If you are looking for a supplement, and you are not sure that you are deficient, you should look for a supplement that is no more than 50 mg a day. Higher levels of zinc can actually interfere with the absorption of copper, which is also an essential mineral.
For information about zinc and other natural supplements you might want to get a subscription to Consumer Labs, which is the only source for objective and unbiased reviews of natural supplements in this country.
Swardfager W, Herrmann N, Mazereeuw G, Goldberger K, Harimoto T, Lanctôt KL. Zinc in depression: a meta-analysis. Biol Psychiatry 2013;74(12):872-878.