Lower serum zinc in major depression in relation to changes in serum acute phase proteins

There is now some evidence that major depression is accompanied by activation of the inflammatory response system (IRS). Other signs of IRS activation, which have been reported in major depression are lowered serum zinc (Zn) and serum albumin (Alb) concentrations. In serum, Zn is closely bound to Alb. The aims of the present study were to replicate previous findings that major depression is accompanied by lowered serum Zn and Alb and to examine whether the decrease in serum Zn may be explained by that in serum Alb. The above variables were determined in 48 major depressed patients and in 15 age-sex-matched healthy volunteers. Serum Zn and Alb were significantly lower in major depressed patients than in normal volunteers. In healthy volunteers and major depressed patients, there were significant and positive correlations between serum Zn and Alb. We found that 53.8% of the variance in serum Zn could be explained by the combined effects of serum Alb and diagnostic classification. The results suggest that lower serum Zn in depression is in part explained by lowered serum Alb and by another depression-related mechanism. It is suggested that lower serum Zn in depression may be secondary to sequestration of metallothionein in the liver, which may be related to increased production of interleukin-6.