Low chromium levels may raise heart attack risk
Low body levels of chromium, a mineral involved in carbohydrate and fat metabolism, are associated with an increased risk of Heart attack, according to a new report. However, the value and safety of chromium supplementation remains to be determined.
Chromium deficiency leads to blood sugar problems that cannot be controlled with insulin, researchers explain in the American Journal of Epidemiology, but the association of chromium intake with heart-related outcomes is largely unknown.
Dr. Eliseo Guallar from the Welch Center for Prevention, Epidemiology, and Clinical Research in Baltimore, and colleagues measured chromium levels in 684 men who survived a Heart attack and in a similar number of men who’d never experienced one. Chromium was measured in toenail clippings because this provides a better indication of levels on a long-term basis compared with measurement of blood levels.
Heart attack Definition
A heart attack (myocardial infarction) occurs when an area of heart muscle dies or is permanently damaged because of an inadequate supply of oxygen to that area.
Chromium levels were lower among older individuals, declining about 9 percent with each decade increase of age, the investigators report. Levels were also lower in those with high blood pressure.
Chromium levels were also 13-percent lower in heart attack patients than in comparison subjects, the researchers note. Further analysis showed that subjects with the highest levels were 35-percent less likely to have a Heart attack than those with the lowest levels.
What Is It?
A heart attack occurs when one of the heart’s coronary arteries is blocked suddenly, usually by a tiny blood clot (thrombus). A heart attack also is called a myocardial infarction or coronary thrombosis. The blood clot typically forms inside a coronary artery that already has been narrowed by atherosclerosis, a condition in which fatty deposits (plaques) build up along the inside walls of blood vessels.
Each coronary artery supplies blood to a specific part of the heart’s muscular wall, so a blockage in an artery causes pain and malfunction in the area it supplies. Depending on the location and amount of heart muscle involved, this malfunction can seriously interfere with the heart’s ability to pump blood. Also, some of the coronary arteries supply areas of the heart that regulate heartbeat, so a blockage sometimes results in potentially fatal abnormal heartbeats, called cardiac arrhythmias. The pattern of symptoms that develops with each heart attack and the chances of survival are linked to the location and extent of the coronary artery blockage.
“Although there are no national survey data on chromium intakes, a study of self-selected diets of US adults indicated that the chromium intake of a substantial proportion of subjects may be well below” the levels that are considered adequate, the researchers point out.
However, “considerably more evidence” is needed to substantiate claims that chromium supplementation will improve sugar control, weight loss, exercise capacity, and longevity, the team says, “as well as to show the long-term safety of chromium supplementation in humans.”
SOURCE: American Journal of Epidemiology, July 15, 2005.
Revision date: June 22, 2011
Last revised: by Janet A. Staessen, MD, PhD