Zinc May Increase Antidepressant Therapy Effectiveness

Healthnotes Newswire (March 4, 2004)—People suffering from depression may experience better results from antidepressant medications by supplementing with zinc, reports a preliminary study in the Polish Journal of Pharmacology (2003;55:1143–7).

Almost 10% of American adults experience some form of depression. The many types of recognized depression include major depression (a severely disabling form), bipolar disorder (sometimes called manic-depressive illness), and a milder form of depression (called dysthymia). Depression may manifest as feelings of sadness, worthlessness, inappropriate guilt, or anxiety; decreased pleasure in activities; excessive weight loss or gain; insomnia or oversleeping; fatigue; an inability to concentrate; and thoughts or plans of suicide. The ability to function normally at work and at home may be compromised during periods of depression.

Prescription medications used to treat depression (such as citalopram [Celexa™] and fluoxetine [Prozac™]) can cause undesirable side effects including changes in sexual function, dry mouth, constipation, headaches, anxiety, and drowsiness.

The new study evaluated the effect of zinc supplementation in people with major depression who were also taking antidepressant medications. Twelve people aged 25 to 57 years were randomly assigned to take one of the following for 12 weeks: (1) 25 mg of zinc per day plus an antidepressant medication, or (2) placebo plus an antidepressant medication. The response to treatment was assessed by using the Hamilton Depression Rating Scale and the Beck Depression Inventory before the trial and at 2, 6, and 12 weeks. Both groups had an improvement in depressive symptoms; however, the zinc-supplemented group showed a statistically significant improvement compared with the placebo group at 6 and 12 weeks.

Zinc is an essential nutrient in the human body that affects the normal functioning of the immune and reproductive systems. It aids in wound healing; functions as an antioxidant, protecting cells from free-radical damage; and also plays a part in the healthy functioning of the brain. Low levels of zinc have been tied to major depressive disorder, and antidepressant therapy for this condition causes blood zinc levels to rise. One study investigated the combination of zinc and antidepressants in animals; when antidepressants were administered at dosages too low to be effective, the addition of small amounts zinc combined to exert an antidepressant effect.

This is the first human study to demonstrate the ability of zinc to enhance the action of prescription antidepressant medications. Other natural substances that have been shown to benefit depression sufferers include folic acid, DHEA, eicosapentaenoic acid (a fatty acid found in fish oil), and St. John’s wort.