Feb. 11, 1998 Protection from strokes may be found in high doses of vitamins B6, B12 and folate. A University of Maryland researcher reports that high doses of B-vitamins lower levels of homocysteine in the blood. Homocysteine is a naturally occurring amino acid, but even mild elevation in the blood is associated with increased risk for stroke, as well as heart attack.
Richard F. Macko, MD, assistant professor of neurology and gerontology, University of Maryland School of Medicine, won this year's Robert G. Siekert New Investigator Award in Stroke from the American Heart Association Stroke Council for his study of the effects of B-vitamin therapy on homocysteine levels and other markers of damage to the cells lining the walls of arteries. The award is given for pioneering stroke research in the first five years after postdoctoral training.
At the 23rd International Joint Conference on Stroke and Cerebral Circulation in Orlando, Macko is presenting results of a double-blind, placebo-controlled study of 50 non-vitamin users who had strokes. Their average age was 67. Those randomly assigned to receive treatment took 100 milligrams of B6, one milligram of B12 and 5 milligrams of folate daily for three months. Folate is a form of the B-vitamin, folic acid.
The dosages are 50 to 100 times higher than the Food and Nutrition Board of the National Academy of Sciences' recommended dietary allowance (RDA).
Levels of homocysteine and thrombomodulin dropped significantly after three months of vitamin therapy, Macko said. Thrombomodulin is part of the body's natural defense system against blood clots. High levels of thrombomodulin circulating in the blood indicate damage to the cells that line artery walls. The vitamin regimen produced no unwanted side effects.
"We were excited to see such a change after just three months," said Macko. About three out of every 10 people over the age of 65 have mild to moderate elevations in blood homocysteine levels. "We don't know if lowering those levels will directly lower the risk for stroke or heart attack," the University of Maryland neurologist said, "but we do have evidence that there is less damage to endothelial cells (the cells lining arteries) when we lower homocysteine, and we do know that damage to endothelial cells is associated with stroke. Since stroke is the third most common cause of death and the leading cause of disability in older people, anything that lowers risk is worth exploring."
Macko's research also revealed an unexpected change. Another protein in blood, von Willebrand's Factor antigen (vWF), rose in study subjects receiving vitamins. The antigen plays a key role in clotting and bleeding.
Macko said he's not sure what the unanticipated rise in vWF means. "We don't know if it increases stroke risk," he said. "We do have evidence of less endothelial cell damage, so we hope that we have simply restored normal vWF synthesis."
Macko's vitamin research was supported in part by the Maryland affiliate of the American Heart Association and by a University of Maryland Geriatrics and Gerontology Education and Research Program grant.
The seven schools at the Baltimore campus of the University of Maryland train the majority of the state's health, social work and law professionals. Based on the founding campus of the University System of Maryland, those schools are: medicine, law, nursing, pharmacy, social work, dental, and graduate programs.
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