Many vitamins useless, study says

C, E and beta-carotene: 'I'm going to have to change my story,' says vitamin advocate

Brad Evenson
National Post

Friday, July 05, 2002

One of the largest studies ever conducted on vitamins found no evidence the pills lessen heart attacks and strokes, cancers, diabetes or other diseases.

The British Heart Protection study, which tracked 20,500 adults for five years, adds to a growing consensus that people who take vitamins are healthier because of their lifestyle, not because they take vitamins.

The researchers conclude that supplementation with "anti-oxidants" -- vitamins E, C and beta-carotene -- is probably a waste of time.

"It did not produce any significant reductions in the five-year mortality from, or incidence of, any type of vascular disease, cancer or other major outcome," says the study published tomorrow in The Lancet, a British medical journal.

Anti-oxidants are among the biggest-selling vitamins.

The findings are deeply disappointing to academics who have called for more research into vitamins.

"You might have hoped that you'd see some benefit with such a huge study, so that's kind of sad, but if that's the way the research is, I'm going to have to change my story, too," says Dr. John Hoffer, a professor of medicine at McGill University and a leading proponent of vitamins.

Although five years is not enough time to properly assess the effects of vitamins on cancer, says Dr. Hoffer, it is adequate to measure their effects on cardiovascular disease.

However, some scientists believe such vitamins and minerals as selenium, vitamins B-6, B-12 and folic acid might still have potent health benefits, especially over longer times.

Vitamins are believed to improve heart health by preventing the oxidation of fat particles in the blood, which leads to hardening of the arteries. Lab tests, animal studies and a few small human studies seem to confirm this result, especially in the case of vitamin E.

"But the available results from much larger randomized trials of several years of vitamin E have been unpromising," the Lancet study says.

In fact, the British researchers instead found a small but worrying effect in this study: The vitamin regimen caused a 3% mean increase in LDL cholesterol, usually known as "bad" cholesterol.

Rather than take vitamins, the researchers suggest, people at risk of heart disease and stroke should take proven medications such as Aspirin, statins, ACE inhibitors, beta blockers and blood pressure drugs, as well as increase exercise and quit smoking.

The study followed 20,536 adults living in the United Kingdom who suffered from coronary disease, hardened arteries or diabetes. Half received a daily dose of 600 milligrams of vitamin E, 250 mg of vitamin C and 20 mg of beta-carotene. The rest took placebo pills.

The results show no difference in rates of heart attack, stroke, cancer, diabetes, osteoporosis, asthma or memory loss.

However, vitamin advocates have argued such studies use dosages too low to offer any benefits. Some doctors believe taking doses of vitamin C as high as 10 grams a day -- 40 times as much as given in the U.K. study -- can prevent cancer and strengthen blood vessels.

The late Nobel Prize winner Linus Pauling was a leading proponent of this theory. He said primitive humans lost the ability, held by most animals, to produce their own vitamin C, resulting in a chronic shortage. In speeches, Dr. Pauling would show audiences a vial containing the vitamin C a goat produces every day, which he said showed why the animals suffer less disease than humans.

"I would trust the biochemistry of a goat over the advice of a doctor," he would say.

Yet, while a few small studies have shown promising results for supplements, most have not. For example, after 12 years of taking beta-carotene supplements, no health benefits have emerged for the 22,000 participants in the Boston-based Physicians' Health Study.

"In the cardiovascular community, we've been pretty convinced by previous studies that the vitamins mentioned in this study are probably not of very much value to the prevention of vascular disease," says Dr. Lyall Higginson, chief of cardiology at the University of Ottawa Heart Institute.

Dr. Higginson said the situation mirrors that of hormone replacement therapy. Estrogen pills, first introduced in 1942, were believed to protect the heart because women who took them tended to have fewer heart attacks. But now doctors believe women who took estrogen pills really owed their health to a tendency to exercise more, smoke less and eat a balanced diet.

A comprehensive study published this week in the Journal of the American Medical Association confirms this belief.

"Not only was there no cardiovascular benefit, there were adverse affects, including blood clots and gallbladder disease," said Deborah Grady, a professor of epidemiology and medicine at the University of California in San Francisco.
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