IARC Handbooks of Cancer Prevention: Carotenoids

Abstract

Since the hypothesis of Peto et al. (1981) that beta-carotene might reduce the incidence of cancer, especially lung cancer, evidence has accumulated from observational studies that people who eat more fruit and vegetables, which are rich in carotenoids, and people having higher serum beta-carotene concentrations had lower rates of lung cancer. However, initial findings from two major clinical trials, ATBC (in Finland) and CARET (in USA), unexpectedly showed that supplemental beta-carotene alone or in combination with retinol appeared to increase the risk of lung cancer, especially among current or former smokers and/or in asbestos-exposed men. In December, 1997, a working group of international experts met in Lyon to evaluate the existing evidence on the cancer preventive activity of carotenoids. [IARC]