Beta-Carotene Be Dangerous? - The
Borneo Post - NH/14/11
RESEARCHERS NOW CALL the supplements worthless. And judging from a recent National Cancer Institute study, they might even be unsafe.
The findings caused a shiver in the nutrition world. Animal tests and human population studies had suggested that the antioxidant known as beta-carotene - a pigment found in fruits and vegetables that the body converts to vitamin A- might ward off cancer and heart disease. Imagine the shock, then, when in 1994 a Finnish study of 29,000 men, all pack-a-day smokers, showed that those on daily supplements of beta-carotene were 18 percent more likely to get lung cancer than those on dummy pills.
So unexpected was the findings, researchers wondered if it was a statistical fluke. But the cancer institute's recent Beta-Carotene and Retinol Efficacy Trial, or CARET, seems to confirm the link. The study involved more than 18,000 men and women -smokers, ex-smokers, or people who'd been exposed to asbestos - on daily doses of either a placebo or a combination of beta-carotene and vitamin A. After four years, the vitamin-takers were 28 percent more likely to have developed lung cancer and 17 percent more likely to have died. The numbers were low enough that they could be a matter of chance. But since the vitamins clearly offered no benefit, the researchers took everyone off the pills.
The decision was announced simultaneously with the results of the Physicians' Health Study at Harvard Medical School - the longest-running study on beta-carotene. For 12 years, it had tracked 22,000 doctors taking either beta-carotene or a placebo every other day. The result: Beta-carotene had no effect, good or bad.
Researchers are now convinced that beta-carotene supplements offer no health protection; however, safety remains a question. The Harvard study found no ill effects, even in smokers, but the suggestion of risk from the Finnish study may never be swept away. So what is an erstwhile fan of beta-carotene pills to do? "Eat lots of fruits and vegetables." says epidemiologist Julie Buring, of the Harvard study. "We know that helps."