Some studies have indicated that dietary carotenoids (such as lycopene and beta-carotene) may impact colorectal cancer risk. For example, one study found that beta-carotene increased colon cancer risk in smokers and decreased it by 40 percent in non-smokers.
Research published this week in the American Journal of Epidemiology examined the results of 11 studies to basically make one big one with about 700,000 participants. The final conclusion was that carotenoids don't play a major role in the development of either colon or rectal cancer.
