Protection from strokes may be found in high doses of vitamins B6, B12and folate. A University of Maryland researcher reports that high dosesof B-vitamins lower levels of homocysteine in the blood. Homocysteine isa naturally occurring amino acid, but even mild elevation in the bloodis 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 HeartAssociation Stroke Council for his study of the effects of B-vitamintherapy on homocysteine levels and other markers of damage to the cellslining the walls of arteries. The award is given for pioneering strokeresearch in the first five years after postdoctoral training.
At the 23rd International Joint Conference on Stroke and CerebralCirculation in Orlando, Macko is presenting results of a double-blind,placebo-controlled study of 50 non-vitamin users who had strokes. Theiraverage age was 67. Those randomly assigned to receive treatment took100 milligrams of B6, one milligram of B12 and 5 milligrams of folatedaily 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 Boardof the National Academy of Sciences' recommended dietary allowance(RDA).
Levels of homocysteine and thrombomodulin dropped significantly afterthree months of vitamin therapy, Macko said. Thrombomodulin is part ofthe body's natural defense system against blood clots. High levels ofthrombomodulin circulating in the blood indicate damage to the cells that line artery walls. The vitamin regimen produced nounwanted side effects.
"We were excited to see such a change after just three months," saidMacko.About three out of every 10 people over the age of 65 have mild tomoderate elevations in blood homocysteine levels. "We don't know iflowering those levels will directly lower the risk for stroke or heartattack," the University of Maryland neurologist said, "but we do haveevidence that there is less damage to endothelial cells (the cellslining arteries) when we lower homocysteine, and we do know that damageto endothelial cells is associated with stroke. Since stroke is thethird most common cause of death and the leading cause of disability inolder people, anything that lowers risk is worth exploring."
Macko's research also revealed an unexpected change. Another protein inblood, von Willebrand's Factor antigen (vWF), rose in study subjectsreceiving vitamins. The antigen plays a key role in clotting andbleeding.
Macko said he's not sure what the unanticipated rise in vWF means. "Wedon't know if it increases stroke risk," he said. "We do have evidenceof less endothelial cell damage, so we hope that we have simply restorednormal vWF synthesis."
Macko's vitamin research was supported in part by the Maryland affiliateof the American Heart Association and by a University of MarylandGeriatrics and Gerontology Education and Research Program grant.
The seven schools at the Baltimore campus of the University of Marylandtrain the majority of the state's health, social work and lawprofessionals. Based on the founding campus of the University System ofMaryland, those schools are: medicine, law, nursing, pharmacy, socialwork, dental, and graduate programs.
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