New Insight Into Cardiovascular Disease
A seldom-measured amino acid that is circulating in your blood may be an indication of cardiovascular disease. It is called homocysteine, and an increasing number of physicians and researchers are acknowledging that high levels of the chemical are associated with heart disease and stroke.
A summary of 15 studies revealed that elevated homocysteine levels produced a 70 percent increase in the risk of coronary artery disease and a greater risk for stroke. Previous studies have shown connections with schizophrenia, Alzheimer’s disease, hypothyroidism and anemia.
However, the evidence is not conclusive. “Five other studies found no link between homocysteine and cardiovascular disease,” says Oklahoma City internist Dr. E. Randy Eichner, a member of the Editorial Board of The Physician and Sportsmedicine, “but six studies did find a relationship. I think the balance of scientific evidence favors a homocysteine/CAD link.”
Atlanta cardiologist Dr. John Cantwell agrees with Eichner. “I recognize it as a possible risk factor, but the only time I measure it is when a person has a family history of heart disease without the more obvious risk factors.”
Dr. M. Rene Malinow, professor of medicine at the Oregon Health Sciences University and one of the nation’s leading homocysteine researchers, says we don’t yet know for sure that it is a cause of atherosclerosis. “We will have to wait for the results of clinical trials, and that could take several years.” Adds Malinow, “Although it is a relatively new risk factor by itself, it is possible that a high homocysteine level combined with traditional risks, such as hypertension or smoking, is even more significant.
Even those who think homocysteine is related to heart disease are not sure why it may have a harmful effect. One theory is that, in elevated amounts, it irritates the inner lining of the arteries and could cause blood clots to form. There is even a possibility that homocysteine levels increase after a stroke, not before.
Prevention
The good news is that a high homocysteine count can be prevented or treated by getting adequate amounts of folic acid (folate). Cantwell tells patients who have high levels to take 0.4 mg of folic acid per day, as well as a multivitamin supplement that includes B6 and B12. A high intake of folate by itself can mask other medical conditions, including a type of anemia.
The U.S. Food and Drug Administration has mandated that all enriched grain products be fortified with folate. Check the labels on cereal boxes. Most of them provide 25 percent of the daily folate requirement and many contain 25-35 percent of daily vitamin B6 and B12 needs. If you are eating a well-balanced diet, you probably don’t need the supplements.
Screening
Homocysteine screening is not very common. The American Heart Association is taking a very conservative position on the issue, saying that it’s too early to recommend general screening. Cantwell points out that the one-year cost of a folate and multivitamin supplement is approximately equal to the cost of a screening test.
Americans are well informed of the risk factors associated with heart disease. Sooner or later, a new one — elevated homocysteine levels — may be added to that list.
Folate is also good for unborn babies.
