The Effect of Beta-Carotene Intake on Lung Cancer Development
Lung cancer remains the leading cause of cancer death in the United States, comprising nearly 30% of all cancer-related mortality. Investigation into nutritional supplementation with beta-carotene as a means of reducing lung cancer incidence remains an active and intriguing area of research. The present review summarizes the salient findings in the literature to date. Although a number of observational studies have suggested an association between carotenoid consumption and reduced lung cancer incidence, two major double-blind, randomized, placebo-controlled trials have not yielded similar results. Not only did these studies fail to demonstrate a protective effect of beta-carotene in lung carcinogenesis, they indicated that beta-carotene supplementation may increase one’s risk of developing lung cancer. Potential reasons for such discrepancies between observational studies and these randomized trials are explored, along with hypotheses concerning the potential carcinogenic risk of beta-carotene. However, such theories remain unsubstantiated at present and therefore no recommendations may currently be made regarding beta-carotene intake for the purpose of reducing lung cancer incidence. Until such contradictions within the literature are resolved from basic science and epidemiologic perspectives, the optimal lung cancer prevention strategy shall remain the traditional triad of smoking cessation, smoking prevention, and avoidance of carcinogenic environmental insults such as asbestos.