Advertising

The Seattle Times Company

NWjobs | NWautos | NWhomes | NWsource | Free Classifieds | seattletimes.com

The Seattle Times

Health


Our network sites seattletimes.com | Advanced

Friday, February 29, 2008 - Page updated at 06:23 AM

E-mail article     Print view      Share:    Digg     Newsvine

Vitamin E won't help, may hurt, cancer study says

Seattle Times health reporter

Should I stop taking vitamin E?

Vitamin E supplements are unnecessary for most people who eat a healthful diet. The recommended daily dose for adults is 15 milligrams from food, which you can get from about 2 ounces of almonds. That's equivalent to 22 international units from natural-source vitamin E or 33 IU of the synthetic form. Other good sources of vitamin E include sunflower seeds, fortified cereal, dark leafy greens and tomato paste. Although there is no clear evidence that extra vitamin E has any health benefits, a quarter of the adults in this UW study took 215 milligrams a day or more. Researchers don't know for certain that excessive vitamin E is harmful.

Source: Harvard School of Public Health, United States Department of Agriculture, Mayo Clinic and Seattle Times reporting

Years of popping vitamins offer no protection from lung cancer, and taking vitamin E at high doses for a long time may even elevate the risk, according to a new study led by researchers in Seattle.

The researchers from the University of Washington and elsewhere tracked 77,719 Puget Sound-area adults age 55 to 76 for an average of four years to see whether multivitamins, vitamin C, vitamin E and folate reduced their odds of getting lung cancer, the leading cancer killer in the United States. The answer was no, regardless of how many vitamins they had taken during the previous 10 years.

The findings join growing evidence discounting the benefits of taking vitamins and minerals through pills instead of through food.

The study will appear in the March 1 issue of American Journal of Respiratory and Critical Care Medicine.

Dr. Tim Byers, a professor of preventive medicine at the University of Colorado who wrote an accompanying editorial to the UW study, said it echoes two decades of research that packaged vitamins just can't mimic the beneficial properties of vitamins in foods.

"Are [supplements] doing much good biochemically? Probably not," said Byers, who was not involved in the study.

Dr. Christopher Slatore, the study's lead author and a senior pulmonary medicine fellow at the UW, said he was not surprised by the results.

In fact, current smokers who took the highest doses of vitamin E — at least 215 milligrams a day for 10 years — were 59 percent more likely to get lung cancer than those who did not take any, a difference that was unlikely to be due to chance.

Among everyone in the study, high vitamin E users had a lung-cancer rate of 209 per 100,000 people, compared with 189 for nonusers.

But even at high doses, the potential for harm from vitamin E paled in comparison to the risk from tobacco use alone. A current smoker in the study was 24 times more likely to get lung cancer than a nonsmoker. Cigarette smoking causes 90 percent of all lung cancers, according to the National Cancer Institute, which funded the study.

More than half of American adults take supplements, many in the belief that they help guard against chronic diseases or cancer. But Byers said little scientific evidence bears that out.

In fact, some vitamins may even be harmful. For instance, taking supplements of beta carotene, a compound found in many fruits and grains, has been shown to increase the chances of developing lung cancer. That's despite evidence that people who eat a lot of fruits are less likely to get the disease.

Byers said the paradox probably was because foods contain not only vitamins but other compounds that may somehow work to protect the body.

That's not to say that all supplements are ineffective, particularly when taken to correct deficiencies. Lack of vitamin D, for instance, may weaken the immune system. Folic acid reduces the risk of birth defects if taken by pregnant women, Byers said.

In addition, Byers said studies have suggested that selenium, a mineral with antioxidant properties, may help prevent prostate and lung cancer.

Still, Byers said, early hopes that supplements, including vitamin E, would reduce the risk of several types of cancer have not been definitively borne out by controlled trials.

So for lung cancer at least, UW's Slatore said, people should give up the notion of swallowing pills to better health.

"If you have $100, you'd be better off to spend it on nicotine patches," he said.

Kyung Song: 206-464-2423 or ksong@seattletimes.com

Copyright © 2008 The Seattle Times Company

U.S. House passes health plan

Dems get past abortion hurdle

The People's Pharmacy: Solutions for painful breast-feeding

H1N1 vaccine-production method faulted

10 ways to take control of your health

Advertising

Marketplace

nwautos

2009's most fuel-efficient sedansnew
Choosing a new sedan? Weigh the impact of your choice on your wallet and on the planet.
Post a comment

Open Houses

Find this weekend's open house listings.
Or search by location: