Researchers have known for some time that high cholesterol isn’t the whole story on heart disease. Dr. Daniel Steinberg, a cardiologist at the University of California, San Diego, theorized more than a decade ago that oxidation-the chemical reaction that causes metal to rust and butter to turn rancid-can also damage coronary arteries. Oxidation involves molecules called free radicals, which crop up in our bodies as oxygen interacts with cells. Unlike a normal oxygen molecule, in which each atom is ringed by pairs of electrons, a free radical carries one electron that lacks a mate. Oxidation occurs when a free radical kidnaps an electron from a neighboring molecule, turning it into a free radical and setting off a corrosive chain reaction.
The process has been implicated in everything from cataracts to cancer-and researchers suspect it is what makes LDL, the bad form of cholesterol, so dangerous. Steinberg and others have shown that when LDL lodges in arterial walls and becomes oxidized, it not only damages nearby tissues but attracts white blood cells. The white cells gorge themselves on oxidized LDL and accumulate within the arterial lining, causing plaques that narrow the arteries (chart). The resulting loss of blood flow can cause everything from chest pain to heart attacks.
There are plenty of reasons for thinking that vitamin E, a natural antioxidant, could interfere with this process. Because it mops up the unpaired electrons on free radicals, vitamin E can keep LDL from oxidizing in a test tube. Experiments have shown that high doses can prevent heart disease in rabbits and monkeys, even when their cholesterol levels are astronomical. And though the evidence has been sketchy, human studies have hinted that the 100- to 600-unit doses available in supplements might offer greater benefits than the tiny doses contained in various foods.
Last week’s findings were the strongest yet. In the larger of the two studies-both carried out at the Harvard School of Public Health and Brigham and Women’s Hospital-a team led by Dr. Meir Stampfer followed 87,000 female nurses from 1980 to 1988. The women, all participants in a wide-ranging health survey begun in 1976, periodically filled out detailed questionnaires about their diets, lifestyles and medical conditions. Analysis showed that when women took vitamin E supplements for at least two years (pushing their daily intake to at least 100 international units), they suffered 41 percent less heart disease than expected. Age, smoking and other risk factors didn’t account for the difference. The second study was based on a similar survey of 40,000 male health professionals. In following the men from 1986 to 1990, epidemiologist Eric Rimm and his colleagues found that those receiving daily vitamin E supplements of at least 100 units for two years reduced their risk of heart disease by 37 percent.
The new findings are sure to bolster supplement sales. As it is, American consumers are popping vitamin E as though their lives depended on it. Sales of the supplement reached $392 million in the United States last year-up from $260 million in 1990-and few cardiologists actively condemn the trend. “There’s growing evidence that antioxidants are effective in preventing atherosclerosis,” says Dr. John LaRosa, a lipid specialist at George Washing-ton University and an American Heart Association designated spokesman on the issue. “All the studies point in the same direction. It’s very exciting because things like vitamin E are not all that expensive compared to the drugs that are used to treat cholesterol.” Indeed, a month’s supply of high-dose capsules can be had for 99 cents in a discount health store.
Despite the mounting evidence, no one is calling vitamin E a proven lifesaver. Some experts worry that high doses could have unexpected long-term side effects (studies of up to six months haven’t documented any). And even the most enthusiastic scientists agree that before they advise everyone to consume 100 or more units a day-a dose that is eight times the current Recommended Dietary Allowance–the benefits must be demonstrated in controlled clinical trials. Rather than simply reporting their own habits, subjects in a clinical trial would receive either a placebo or a specified dose of vitamin E every day, and the effects would be carefully measured. Several such studies are now in the works. But health-conscious scientists aren’t waiting idly for the results to come in. “I eat carefully and exercise,” says Rimm, the researcher who headed the men’s study. “And for good measure, I take 200 units of vitamin E every day.”
Researchers suspect that heart disease begins when LDL cholesterol undergoes oxidation (the process that causes rust). Vitamin E may block that process.
Low-density lipoproteins(LDLs) accumulate within arterial wall and become oxidized
Oxidized LDLs, which can damage arterial tissue, attract white cells
The white blood cells become engorged with oxidized LDLs and accumulate within arterial walls, eventually narrowing the artery
