Beta-Carotene Supplements
Beta carotene is a carotenoid, like lycopene, that is a strong antioxidant and thus has been suggested to have many health benefits. It is primarily found in the yellow and orange vegetables, such as squash, carrots, and pumpkin, but also in green leafy vegetables, such as spinach. Beta carotene, unlike lycopene, is a precursor to vitamin A; in other words, it leads to the formation of vitamin A. This has resulted in confusion about the protective effect of beta carotene on prostate cancer. Studies on vitamin A have had conflicting results. Some show a protective effect, but others show an increase in risk with greater intakes or serum levels of vitamin A. But vitamin A comes from animal sources as well as carotenoids, like beta carotene. Studies that show an increase in risk of prostate cancer have generally included greater consumption of fat, too.
Concerning the consumption of beta carotene, overall, the evidence appears to support a small protective influence. But several studies, including the best long-term study, the Health Professionals Follow-up Study, have found no effect. Vitamin A did not increase risk, and taking a beta-carotene supplement did not reduce risk. Some evidence suggests that beta-carotene supplements may reduce the risk of prostate cancer but only in men who have low levels of beta carotene in their blood. Other evidence suggests that smokers should avoid taking beta-carotene supplements. An increase in risk of lung cancer was observed in smokers taking beta carotene. Other data suggests that there may be an interaction between beta carotene and alcohol too. Beta carotene was found to reduce the risk of prostate cancer in nondrinkers but to increase the risk in drinkers. All of this evidence can be confusing. The best advice is probably to avoid taking a beta-carotene supplement but try to get ample amounts of beta carotene, along with other carotenoids, in your diet. Do this by consuming plenty of colorful vegetables, such as tomatoes, carrots, squash, pumpkin, and spinach, on a regular basis.
