High Levels Of Homocysteine Raise Death Risk From Heart Disease
(excerpted from a reportd on September 7, 1999, The Medical Tribune)
Elevated levels of a blood chemical associated with heart disease raise an individual's five-year risk of dying, say researchers.
Since 1969, heart disease experts have realized that high homocysteine levels and clotted blood vessels seemed to simultaneously occur in many patients. In more recent years, researchers have linked elevated amounts of homocysteine in the blood with heart disease.
But they have differed on the question of whether the blood chemical is merely associated with disease or truly causes it, and thus deserves to be controlled in patients as rigorously as cholesterol levels.
Now, in an attempt to quantify the risk from homocysteine, a series of papers has appeared in the Tuesday issue of the journal Annals of Internal Medicine. In one study, led by Dr. Jeremy D. Kark of Hadassah University Hospital in Jerusalem, researchers followed 1,788 people, starting in 1985, looking at their homocysteine levels. People in the highest 20 percent of homocysteine levels doubled their risk of dying within five years, they report.
Another study led by Dr. Andrew G. Bostom of Memorial Hospital of Rhode Island in Pawtucket, looked at 1,947 residents of Framingham, Mass. They found that individuals in the highest 25 percent of homocysteine levels in their blood plasma had 1.8 times the risk of suffering a stroke as people in the lowest quarter. Study participants averaged 70 years of age, cautioned the researchers, so their findings mainly apply to the elderly.
"Do we need reference ranges for plasma homocysteine levels? The answer has to be yes," commented Dr. Ian Graham of the Royal College of Surgeons and Trinity College in Dublin, in an editorial accompanying the studies. Both articles estimated concentrations of homocysteine exceeding a rough value of 1.9 milligrams per liter of blood as putting patients in the greatest danger. He advised patients in these ranges to quit smoking and take extra care to control their cholesterol and blood pressure levels.
A third study, performed by nutrition researcher Jacob Selhub and colleagues at Tufts University in Boston, reinforced earlier findings of vitamin B deficiencies among people with high homocysteine levels. Selhub's team examined 8,086 people 12 years and older as part of the Third National Health and Nutrition Examination Survey. They found that homocysteine concentrations increased with age and that two-thirds of the people with high levels suffered from a vitamin B deficiency.
Graham advised patients with high homocysteine levels should take at least 400 milligrams of folic acid, a B vitamin, each day.
Because none of the studies conclusively prove that homocysteine causes disease, he held off on recommending patients take vitamin B12 or B6.
However he suggested people eat, "plenty of fruits and vegetables," rich in vitamin B, to keep levels of the blood chemical down.
"Why Graham feels that the lack of ‘conclusive proof’ warrents a warning against taking Vitamin B12 or B6 supplements is something that utterly baffles me," comments Don Goldberg, R.Ph., of Willner Chemists. "The possible benefit of B-complex vitamin supplements is so great, and the cost so small... how can you in good conscience not urge everone to take supplemental B vitamins?"
"Certainly, we do not want to give people the mistaken impression that taking a vitamin supplement can take the place of eating health food. But we certainly should be able to avoid turning people away from healthy food in ways other than continuing to recommend against supplements, supplements