A trip to the health food store can be daunting these days. The consumer is typically confronted by shelf after shelf of vitamins, minerals, herbs, and other so-called natural substances, all touted as enhancing well-being in some way. Many of these over-the-counter products make subtle claims about their effects on mood, thinking, or energy -- without providing scientific data to back up those claims.

Because many of these preparations are classified as "food substances," the U.S. Food and Drug Administration (FDA) cannot regulate them as real drugs. In effect, it's up to the FDA to prove that a food substance is unsafe, rather than the job of the manufacturer to show it is safe. What is the evidence that vitamins, minerals, or similar substances have an effect on mood disorders? And can these substances actually improve moods or even treat depression?

Food Fads Lead to Vitamin Deficiencies

Vitamin deficiencies are rare in the United States and other developed countries. In fact, vitamin excess may now be more common than vitamin deficiency. When deficiencies do occur, they're usually due to food fads that lead to medical conditions from poor absorption of nutrients in the intestine, or inborn errors in the way nutrients are handled. Alcoholism is also a major cause of vitamin deficiencies, owing to poor nutrition, impaired absorption of nutrients, and other factors. The elderly and those with mental illness or mental retardation are also at risk, usually due to poor nutrition and self-care.

Occasionally there are individuals whose depression, anxiety, or memory problems are caused by a deficiency in some vitamin, mineral, or trace element -- most commonly, one of the B complex vitamins. Deficiencies of thiamine (vitamin B1), niacin, pyridoxine (B6), or cobalamin (B12) sometimes produce mental or emotional problems, including depression. Folic acid deficiency may cause problems with mood and mental function. While only a small minority of severely depressed persons suffer from such vitamin deficiencies, this problem must be ruled out when the clinical picture raises suspicions -- for example, when a depressed individual has a history of bowel surgery that may have led to malabsorption of B vitamins. If depression is due to a vitamin deficiency, treatment must include replacement or supplementation of the vitamin before the patient can fully recover.

Interest in Chromium

Recently there has been great interest in a trace element called chromium. (Trace elements are metals, such as zinc or copper, that are found in very small amounts in the human body and are necessary for various vital functions.) It has been known for many years that chromium is essential for the way our bodies handle sugar. Chromium deficiency makes it hard for cells and tissues to make use of glucose, a simple sugar. This problem is especially serious in people with diabetes, in whom deficiency of the hormone insulin already creates problems with high blood sugar. But the role of chromium in depression is only now emerging. A recent study by Dr. Malcolm McLeod and his colleagues investigated the use of chromium in five patients with a chronic form of depression called dysthymia. In one case, a patient who had not responded well to a Prozac-type antidepressant decided on his own to add chromium to his medication. Within a few days he was feeling dramatically better. Several other cases reported by McLeod also seemed to show marked improvement when chromium was added to the patients' regular antidepressant medication.