Vitamin E flexes plaque-busting muscle.

Vitamin E may slow or even reverse the fatty buildup on artery walls that can lead to heart attacks or stroke, according to a new study of monkeys. Researchers caution, however, that they have yet to confirm this finding.

Vegetable oils, nuts and whole grains generally are rich in vitamin E. This nutrient belongs to a group of compounds believed to protect against atherosclerosis, the accretion of fatty plaques on blood-vessel walls *SN: 11/17/90, p.308).

Now, Anthony J. Verlangieri and Marilyn J. Bush at the University of Mississippi in Oxford report a study of monkeys that adds to the evidence that vitamin E wards off atherosclerosis.

In their study, which appears in the April JOURNAL OF THE AMERICAN COLLEGE OF NUTRITION, the Mississippi researchers gave six monkeys regular monkey chow. Sic other primates got a diet laced with cholesterol and lard, as well as a twice-a-day banana-flavored placebo pill. To see whether vitamin E could prevent atherosclerosis, another six got the same high-fat diet, but their banana-flavored treat contained vitamin E.

The team used ultrasound imagined to look for fatty plaques in the carotid arteries, large vessels in the neck that carry oxygenated blood to the brain.

After 36 months, the monkeys eating regular chow showed no sign of atherosclerosis. Monkeys eating a high-fat diet along with a vitamin E pill showed an average of 61 percent blockage of their carotid arteries. However, monkeys popping the placebos and eating a fat-choked diet fared much worse: Their ultrasound tests revealed about 87 percent blockage of the carotid arteries.

"The numbers are small, but I think it's quite an exciting observation," comments Lawrence J. Machlin, a vitamin E researcher at Hoffmann-LaRoche, Inc., in Nutley, N.J.

Machlin speculates that vitamin E may help slow the formation of plaque through its antioxidant activity. Scientists believe that antioxidants help protect blood vessels by neutralizing free radicals, dangerous substances that can damage blood-vessel walls. In an effort to repair the damage, blood platelets and cholesterol adhere to blood vessel cells, thus creating the artery-narrowing plaques that can cause heart attacks.

Verlangieri notes that other nutrients, including vitamin C, act as antioxidants. Indeed, he has unpublished data suggesting that vitamin C also helps prevent atherosclerosis in monkeys eating high-fat diets.

Prevention isn't the only way to beat cardiovascular disease. The current study includes data on six monkeys who received vitamin E after they had developed plaques blocking about 35 percent of their carotid arteries. Two years after beginning vitamin E therapy, the monkeys' blockage had declined to an average of 18 percent. That result surprised Verlangieri, who says: "We didn't think there would be such significant regression."

Nonetheless, Machlin views the regression data with caution. Although many other studies have documented vitamin E's ability to slow the progress of atherosclerosis, no one has proved the nutrient's ability to dissolve existing plaque, he says.

Both scientists agree that confirmation of vitamin E's potential for the prevention and treatment of coronary artery disease must await further work. "In the end, what really needs to be done are large-scale human intervention trials," Machlin says.