NEW ORLEANS, Nov.12--Cardiologists at the University of Maryland Medical Center in Baltimore have found that blood vessels do not dilate normally after a person eats a high fat meal. But their further study suggests that taking a high dose of vitamins C and E right before a fatty meal may prevent the impairment of the blood vessels.
Their study, which is the first to examine the effect of vitamins on blood vessels after a high-fat meal, will be presented today at the American Heart Association's 69th Scientific Sessions.
The researchers tested 20 adult volunteers who ate a 900-calorie, fast-food meal of eggs, sausage, and hash browns that was 50 percent saturated fat. To study the impact on blood vessels, they used ultrasound to measure the ability of blood vessels in the upper arm to dilate normally after blood flow was temporarily cut off by an inflatable blood pressure cuff. After the cuff was removed, blood vessels should have dilated to allow a higher volume of blood to flow through.
Each volunteer was evaluated before, during, and after the high fat meal. Later, on another day, the test was repeated, but the volunteers took 1 gram of vitamin C and 800 I.U. of vitamin E before consuming the meal.
The group's average baseline blood vessel dilation before a fatty meal was 21 percent. Two hours after the meal, the blood vessels could only dilate an average of 12 percent. It dropped to 8 percent four hours after the meal. However, when the vitamins were taken before the meal, the average dilation two hours after the meal was 17 percent. After four hours, it remained the same.
"It is important for our blood vessels to be able to dilate normally to accommodate blood volume. Otherwise, we are at increased risk of a heart attack or other cardiovascular problems," says Gary Plotnick, M.D., professor of medicine at the University of Maryland School of Medicine and lead author of the study.
"The bottom line is that four hours after a fatty meal, the average blood vessel dilation was only 8 percent. But when our volunteers consumed the vitamins with their meals, dilation remained near baseline levels, which we found intriguing," says Plotnick.
"Our study raises the interesting possibility that we may be able to influence minute-by-minute changes that occur in blood vessels that lead to heart and blood vessel disease," says Mary C. Corretti, M.D., an assistant professor of medicine and co-author of the study.
The researchers stress that more study is needed to learn why a high-fat meal impairs the normal dilation of blood vessels, and also to find out how and why vitamins may blunt that process. One theory is that fat may stop blood vessels from releasing nitric oxide, a substance that allows vessels to dilate.
Robert A.Vogel, head of Cardiology at the University of Maryland Medical Center, was also a co-author of the study.
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