A new, well-designed but small study has found that people with mild type 2 diabetes who took 1,000 micrograms per day of chromium picolinate along with an oral diabetes medication achieved better glucose control than people who took a placebo with the same medication. They also gained less weight during the 10-month study than would have been expected. The study, published in the August 2006 issue of the journal Diabetes Care, provides another bit of evidence that chromium picolinate may help some diabetes patients. But the study was much too small--only 25 people in all--to resolve the debate over whether this heavily promoted supplement is truly helpful.

A follow-up study involving 90 subjects is in the works, says one of the study's principal investigators, William T. Cefalu, M.D., chief of the division of nutrition and chronic disease at the Pennington Biomedical Research Center in Baton Rouge, La.

The idea that chromium picolinate may help control or prevent diabetes is theoretically plausible: Chromium is known to enhance the action of insulin.

The patients in the new study had diabetes mild enough that they did not need to take insulin and required only one oral diabetes medication. By contrast, a study published a few months earlier looked at severe diabetics who needed high doses of insulin; chromium picolinate had no effect on their blood sugar control. Nor does chromium picolinate seem to prevent the development of diabetes in susceptible people.

"There have been lots of studies on chromium, and lots of inconsistency," says Philip Gregory, Pharm.D., an analyst with the Natural Medicines Comprehensive Database, an independent group that evaluates nutritional supplement science. "Therefore, we can't consider chromium to be a reliably effective treatment."