May 25, 2005

Chromium Supplements Good for the Diabetic Heart

NEW YORK (Reuters Health) - Chromium supplementation may be good for the heart in people with type 2 diabetes, according to study findings. It appears to lead to a shortening of a harmful heart rhythm, which may lower cardiovascular risk in type 2 diabetics.

The heart rhythm disturbance known as a prolonged QT interval has been linked to fatal heart arrhythmias. Therefore, the changes in QT interval observed with chromium supplementation in patients with type 2 diabetes may also translate into a survival benefit, study investigator Dr. Bojan Vrtovec from Ljubljana University Medical Center in Slovenia told Reuters Health.

In the study, researchers had 30 diabetic patients take 1000 micrograms of chromium daily for 3 months followed by an inactive placebo for 3 months. Another 30 diabetic patients started with 3 months of placebo and then crossed over to chromium for 3 months.

At the start of the trial, the QT interval viewed on a standard electrocardiogram or ECG was similar in both groups -- 422 milliseconds in the first group and 425 in the second group.

However, at 3 months, the QT interval was significantly shorter in the supplementation group (406 milliseconds) than in the placebo group.

In the next 3 months, QT shortening was observed in the second group but not in the first group. At the end of the study, the OT interval duration was similar in both groups and was markedly lower overall than at the start of the trial before chromium supplementation. This study shows that increased intake of chromium may lower cardiovascular risk in type 2 diabetic patients, the researchers say.

They also note in the American Heart Journal that blood insulin levels decreased significantly after 3 months of chromium supplementation and this may be partly responsible for the QT interval shortening.

A prolonged QT interval has been associated with high blood sugar levels, high insulin levels and reduced sensitivity to insulin in type 2 diabetics, they explain. Chromium supplementation improves sensitivity to insulin, lowers blood insulin levels and improves glucose homeostasis.

Source: http://www.nlm.nih.gov