Can Beta-Carotene Fight Off Cancer?

Question: Can Beta-Carotene Fight Off Cancer?

Your body takes beta-carotene from foods and supplements and produces vitamin A. Wouldn't it be great if taking a beta-carotene supplement could help reduce your risk of cancer? Given everything we known about antioxidants and vitamins, it seems likely that upping your daily intake of beta-carotene would be a good thing, cancer-risk wise. Here's what researchers found:

Answer: Researchers got 7,600 women over the age of 40 to take a beta-carotene supplement or a placebo every other day (the supplement was 50 milligrams of beta-carotene). They then monitored the women in the study for 9 years. In that time, 624 of the women in the study developed some type of cancer (with 176 dying from cancer).

After looking at the data, researchers found no link between cancer risk and whether people were taking a placebo or the beta-carotene study. Bottom line: For the women in this study (over aged 40), beta-carotene had no effect on cancer risk.

In a separate study, researchers looked at the effects of beta-carotene on cancer risk in people who smoked. This study covered 29,133 male smokers who took 20 milligrams of beta-carotene, a placebo, a form of vitamin E or both beta-carotene and vitamin E. For the men who took beta-carotene only, there was an 18% increase in their rate of lung cancer and an 8% increase in overall mortality. In other words, for these men who smoked cigarettes, beta-carotene increased their risk for lung cancer and their overall risk of death over a 5- to 8-year period.

So it looks like beta-carotene is a bit of a bust for cancer prevention and can, in fact, be potentially dangerous in people who smoke. To avoid worrying about these types of issues, get your nutrients from real food, not from supplements.

_Sources:

Lin, J. Journal of the National Cancer Institute, Jan. 7, 2009; vol 101: pp 14-23.

New England Journal of Medicine 1994;330:1029).