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: American Heart Journal April 2005.
