March 15, 2005 -- Vitamin E harms more than it helps, a large study shows.
Vitamin E is a powerful antioxidant, thought to clear the body of harmful oxygen compounds called free radicals. By soaking up free radicals, researchers hoped that vitamin E would prevent cancer and heart disease.
That doesn't happen, finds Eva Lonn, MD, of McMaster University in Hamilton, Ontario, and colleagues. Lonn led a seven-year-long, international study that enrolled thousands of people at high risk of heart disease. The findings added to suspicions raised by prior studies: Vitamin E isn't worth it.
"We saw definitely no benefit, and at least the potential for harm," Lonn tells WebMD. "Now the overwhelming evidence from many studies is that vitamin E provides no protection against heart disease, stroke, or cancer."
Lott and colleagues report their findings in the March 16 issue of The Journal of the American Medical Association.
Vitamin E Harm: Slight but Significant Risk
Lonn's study enrolled nearly 10,000 people with heart disease, peripheral artery disease (also commonly called poor circulation, a disease of blood flow through the arteries) or diabetes. This put them at very high risk of heart attack and stroke. All were over age 55. Half got high-dose vitamin E -- 400 IU every day (about 400 milligrams) -- and half got fake pills that looked the just the same.
But many experts wondered whether that was long enough for vitamin E to help. So Lonn and colleagues extended the study for another three years.
Unexpectedly, they did see one difference. Patients taking vitamin E had significantly more heart failure.
Vitamin E was linked to a 13% higher risk of heart failure and a 21% increased risk of hospitalization for heart failure. That's a pretty small risk. But since the vitamin did no good at all, it's a risk not worth taking.
"If there is no benefit from taking something, you shouldn't take even a small risk of harm," Lonn says.
There is no need to worry if you take a multivitamin that contains recommended amounts of vitamin E. But Lonn advises people not to take pills containing high amounts (400 IU or more) of vitamin E.
Is Vitamin E Dead?
B. Greg Brown, MD, PhD, head of the atherosclerosis research lab at the University of Washington School of Medicine, was one of the first scientists to suggest that vitamin E and other antioxidant vitamins may not work the way they were supposed to.
"Vitamin E has been very clearly shown to be of no benefit to the general problem of cancer or heart disease," Brown says. "Studies are still looking at whether vitamin E can help prostate cancer, [mouth and throat] cancer, and severe macular degeneration. But all in all, there is relatively little hope for a major effect. There's not a lot of hope for vitamin E. It's proven to be without benefit."
Brown's editorial accompanies the Lott study in the March 16 issue of JAMA.
The Real Vitamin E Harm
What worries Lonn and Brown isn't heart failure caused by vitamin E.
"The scary thing is not that vitamin E will cause harm. It's that people will take something that does no good instead of something we know will help," Lonn says. "Often people think, 'Well, I am going to be fine because I am taking a bunch of vitamins.' We see that even in people who have had two or three heart attacks already. They won't take their medications, but a bunch of vitamins they will take. That is where the damage lies rather than in the small risk from the vitamin E pill itself."
Brown, a cardiologist, says he far too often sees the same thing.
"The one thing that is really of concern is that a person will say, 'I am taking a vitamin, so I don't have to exercise or quit smoking or take a cholesterol-lowering drug," he says. "So that can be harmful in turning people away from proven therapies toward those with no benefit. Maintaining that position of zealotry can be more harmful than simply taking the vitamin itself."