Two new studies of more than 120,000 men and wome strongly suggest that supplements of vitamin E can significantly reduce the risk of disease and death from fat-clogged coronary arteries. But the researchers and other experts cautioned against rushing out to buy the vitamin supplements before further clinical trials confirm that they are beneficial and safe.
The studies, by researchers at the Harvard School of Public Health and Brigham and Women's Hospital in Boston, showed that initially healthy people with the highest daily intakes of vitamin E developed coronary disease at a rate about 40 percent lower than comparable men and women whose intake of this vitamin was lowest. The preventive effects of vitamin E occurred independently of any change in blood levels of cholesterol.
The greatest protection was found at levels of about 100 international units of vitamin E a day over a period of more than two years. The federal recommended daily allowance for vitamin E is 15 units, and most people consume fewer than 25 units from foods such as vegetable oils, wheat germ, seeds, whole grains and nuts.
The researchers said vitamin E,as an anti-oxidant, might reduce heart disease by having an effect on low-density lipoprotein (LDL) cholesterol, the so-called bad cholesterol. Studies have shown that this type of cholesterol damages arteries primarily after it has been oxidized.
The new findings, which appear Thursday in the New England Journal of Medicine, are some of the first to find health benefits from taking large-dose vitamin supplements. Most medical experts have viewed "megadoses" of vitamins as a popular remedy whose value is unproven.
While a person might reasonably conclude from the new findings that it would be wise to take large doses of vitamin E supplements daily, its long-term safety has not been established. But specialists say that many people take upward of 400 units of vitamin E supplements a day with no apparent adverse effects.
Although specialists expressed enthusiasm for the results, the researchers who conducted the new studies and independent scientists cautioned against "leaping on the supplement bandwagon," said Dr. Claude L'Enfant, director of the National Heart, Lung and Blood Institute in Bethesda.
Dr. L'Enfant said in an interview that recommendations about taking vitamin E supplements must await the completion of more stringently designed clinical trials that clearly establish the benefits and define possible risks.
Dr. Michael Brown of the University of Texas Southwestern Medical Center in Dallas said, "Vitamin E may help to minimize the toxicity of LDL cholesterol, but the real problem is that the LDL levels we accept as normal are really unnaturally high." Dr. Brown and his colleague, Dr. Joseph Goldstein, shared a Nobel Prize for elucidating how the body processes cholesterol.
While vitamin E may seem innocuous, "the doses that seem protective are no longer in the category of vitamin; they are really drugs, and all drugs must be studied to determine their relative benefits and risks," Dr. Brown said.