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---------------------------------------------------------------------- Vitamins Block Fatty Meal's Artery Effect ---------------------------------------------------------------------- NEW YORK (Reuters) -- Taking vitamins C and E before eating can block some of the negative effects of a high-fat meal on artery linings, a new study shows. Researchers at the University of Maryland School of Medicine in Baltimore studied the effect of eating a high-fat meal on the function of the endothelium lining of a major artery in 20 healthy people between the ages of 24 and 54. They found that a single high-fat meal "reduces endothelial function for up to 4 hours" -- however, taking the antioxidant vitamins C and E before the meal blocked this effect. The findings presented in this week's issue of The Journal of the American Medical Association suggest that these antioxidant vitamins help preserve the normal function of endothelial cells that line blood vessel walls, thus preserving the ability of arteries to dilate and keep blood flowing smoothly. Researchers say the study results may help explain the role of antioxidant vitamins in the prevention of atherosclerosis, the narrowing of the coronary arteries linked to an increased risk of heart disease. "We undertook the study because there are some people who eat a lot of fruit and vegetables who seem to be at low risk for heart disease. In fruit and vegetables are vitamin C and vitamin E," says the study's lead author, Dr. Gary D. Plotnick, a professor of medicine at the University of Maryland School of Medicine. For the study, Plotnick enlisted himself and 19 of his co-workers, ages 24 to 54, all with normal blood cholesterol levels. Once a week for three weeks, the group ate one of three breakfasts: [a] a high-fat meal of 900 calories with 50 grams of fat (of which about 15 was saturated fat); [b] a 900 calorie low-fat meal with 0 grams of fat; or [c] a high-fat meal taken after swallowing 1,000 milligrams (1 gram) of vitamin C and 800 international units (IU) of vitamin E. Ten subjects also ate the low-fat meal following "pretreatment" with the vitamins. Before and after the different meals, the researchers used high-resolution ultrasound images to observe dilation of the brachial artery in the arm. A tourniquet was applied for five minutes to the upper arm and then the blood flow observed upon its release. This test served as a measure of blood vessel endothelial function. "If the endothelium is normal, it responds by releasing nitric oxide, which enables dilation. If the vessel is abnormal, the same stimulus (tourniquet release) doesn't cause it to dilate as much," Plotnick explains. "And what we saw was that, for up to four hours (after the high-fat meal alone), the health of the blood vessel became abnormal," Plotnick says. No significant changes were observed in dilation following the low-fat meal alone, the high-fat meal with vitamins, and the low-fat meal with vitamins. Plotnick and his colleagues say the high-fat meal reduces endothelial function "probably through the accumulation of triglyceride-rich lipoproteins (blood fats)." "Pretreatment with antioxidant vitamins eliminated the decrease in endothelial function following the high-fat meal, but did not increase vasodilation after the low-fat meal," the researchers write. "Our findings support the use of a low-fat diet with appropriate vitamin administration in addition to (high cholesterol) therapy to prevent and manage coronary artery disease," they conclude. "These are preliminary data," Plotnick cautions, "and it doesn't mean you should go out and buy vitamins, take them, and then eat whatever you want." SOURCE: The Journal of the American Medical Association (1997;278:1682-1686) 1997, Reuters Health eLine <http://www.medscape.com/reuters/wed/t1125-6f.html> ---------------------------------------------------------------------- janet [log in to unmask]