Beta carotene supplements do not protect Americans against cancer or heart disease, and might actually increase smokers’ risk of deadly lung tumors, the government declared Thursday.
National Cancer Institute researchers shut down a vitamin study of 18,000 smokers last week, almost two years early, because too many of those being given high doses of beta carotene were dying.
There were 28 percent more lung cancers and 17 percent more deaths among beta carotene takers than smokers who took dummy pills - almost mirroring a 1994 Finnish study that first raised questions about this carrot-derived vitamin’s safety.
A second U.S. study fed megadoses of beta carotene to 22,000 doctors for 12 years and found no evidence of harm in either smokers or non-smokers. But it also found that people who took beta carotene pills wasted their money.
“Beta carotene is no magic bullet,” concluded NCI Director Dr. Richard Klausner.
Is it really dangerous for smokers? Klausner’s not sure, but said, “There is one very clear message: The only way to reduce your (cancer) risk is to stop smoking.”
But the doctors emphasized that doesn’t mean people should avoid carrots and other vitamin-packed vegetables and fruits. These studies merely prove that popping the pills can’t replace the complex mix of natural chemicals - and the high-fiber, low-fat benefits - in those foods.
“A beta carotene supplement neither substitutes for a good diet nor compensates for a bad one,” said Dr. Charles Hennekens of Harvard Medical School, who led the physicians’ study.
Beta carotene is the vegetable form of vitamin A, found in dark yellow or dark green vegetables and fruits. Americans usually consume 2 or 3 milligrams of it daily, and many multivitamins contains another 6 or so milligrams.
The NCI-sponsored studies fed people about 10 times the average American’s consumption, on the theory that mega-doses might protect against heart disease or cancer by soaking up dangerous oxygen molecules that can damage cells. That theory fuels the $75 million to $100 million in annual sales of beta carotene supplements.
“Disappointingly,” Klausner said, the studies “revealed no benefit.”
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