Beta-carotene supplements, believed to be cancer preventatives, paradoxically could be surpressing other cancer fighters in the body, especially in someone with a low nutritional status.
Instead, a better source of beta-carotene may be from fruit and vegetables.
Dr Alan Gaby believes his theory may explain the seemingly bizarre findings of a Finnish study in 1994, which found that a group of smokers given beta-carotene supplements suffered more cases of lung cancer than those given a placebo.
The clue to this surprising finding may be found in a test of two volunteers who took 25 mg of beta-carotene and 25 mg of the carotenoid canthaxanthin. When they were taken together, the blood concentration of canthaxanthin fell by 38 per cent, suggesting that beta-carotene inhibits canthaxanthin (Townsend Letter for Doctors, December 1995).