Supplements containing the mineral chromium may be useful in treating some cases of depression -- particularly when carbohydrate craving is a prominent symptom, a new study suggests.

The study, of 113 people with a disorder known as atypical depression, found that although chromium picolinate supplements were no more effective than an inactive pill in relieving depression overall, they did appear to aid certain, mainly appetite-related, symptoms.

Moreover, a subgroup of patients -- those who said they had "irrepressible cravings" for sweets and starches -- did show a general improvement in depression symptoms after taking the supplement.

Exactly why chromium supplements seemed to aid these patients is not completely clear. However, the study authors speculate the improvements in the body's use of insulin, the key hormonal regulator of blood sugar, may be the reason.

"While these findings require replication in a prospective trial, they suggest that chromium picolinate may be beneficial for patients with atypical depression who are also high carbohydrate cravers," Dr. John P. Docherty and his colleagues report in the Journal of Psychiatric Practice.

Docherty is an adjunct professor of psychiatry at Weill Medical College of Cornell University in New York, and head of Comprehensive Neurosciences, Inc., which contracts with drug and supplement makers to conduct clinical trials of their products. Nutrition 21, Inc., which markets the Chromax supplement used in the study, funded the research.

Chromium, a mineral that the body needs in trace amounts, is found naturally in meat, whole grains and certain vegetables and fruits like broccoli, potatoes and apples. The mineral enhances the action of insulin and helps break down carbohydrates, fat and protein. Because of this, chromium supplements are being studied for the treatment and prevention of diabetes, in which the cells of the body lose their sensitivity to insulin.

Researchers have long noted associations between depression, diabetes and heart disease, Docherty and his colleagues point out. For example, people with major depression have been found to have higher rates of insulin resistance, a precursor to diabetes.

There has been speculation that insulin resistance might be behind the symptoms of overeating, carbohydrate craving and weight gain seen in some people with depression.

These symptoms characterize atypical depression, in particular -- which, despite its name, is a common form of depression that, besides overeating and weight gain, may involve excessive sleeping and a feeling of heaviness in the arms and legs. People with this form of depression also show "mood reactivity," which means they brighten in response to positive happenings in their lives.

In the new study, patients were randomly assigned to take either chromium supplements or a placebo everyday for 8 weeks. At the end of the study, the rate of improvement in overall depression symptoms was similar in both groups.

However, the chromium group did show greater improvement in hunger, overeating, carb craving and daily mood changes. And nearly two-thirds of the 41 patients with significant carb cravings saw improvements in their depression symptoms in general -- compared with one-third of those who took a placebo.

Further studies, the researchers conclude, are needed to see whether chromium specifically helps depression patients who tend to overeat and crave sugars and starch-and whether higher doses of the mineral might also aid their overall depression symptoms.

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SOURCE: Journal of Psychiatric Practice, September 2005.