Beta-carotene, Retinol, and Lutein Supplements May Increase Risk of Lung Cancer
According to the results of a study published in the American Journal of Epidemiology, use of individual beta-carotene, retinol, or lutein supplements is linked with an increased risk of lung cancer.
Many studies have suggested that a diet rich in fruits and vegetables may reduce the risk of cancer. Although fruits and vegetables contain many potentially beneficial compounds, researchers have speculated that at least some of the benefits provided by these foods could be explained by the antioxidant nutrients that they contain. These antioxidants include vitamin C, vitamin E, and the carotenoids (such as beta carotene).
Unfortunately, several large randomized studies of antioxidant supplements have not found a beneficial effect on cancer risk. In some cases, certain types of supplements have even been found to increase cancer risk. The CARET and ATBC trials, for example, both reported that high-dose beta-carotene supplementation increased the risk of lung cancer among smokers. 
To explore the health effects of dietary supplements in the general population, researchers conducted a study known VITAL (VITamins And Lifestyle). The study, based in Washington State, enrolled more than 77,000 people between the ages of 50 and 76. Study participants completed a questionnaire about their use of dietary supplements during the previous 10 years. Information was collected about both multivitamins and individual dietary supplements.
During follow-up, a total of 521 of the study participants developed lung cancer. Because a previous analysis of the data from this study showed that multivitamins do not increase risk of lung cancer, the current analysis focused on several individual dietary supplements: beta-carotene, retinol, total vitamin A, lutein, and lycopene. Individual supplements often contain higher doses of particular nutrients than would be found in a typical multivitamin.
- Use of lutein supplements was linked with a twofold increase in overall risk of lung cancer.
- Use of beta-carotene supplements for at least four of the previous 10 years was linked with a more than threefold increase in risk of small cell lung cancer
- Use of retinol supplements for at least four of the previous 10 years was linked with a 1.8-fold increase in risk of non–small cell lung cancer.
- Use of lycopene supplements was not linked with risk of lung cancer.
The researchers conclude that long-term supplementation with beta-carotene, retinol, or lutein may increase the risk of lung cancer.
 Omenn GS, Goodman GE, Thornquist MD et al. Risk factors for lung cancer and for intervention effects CARET, the Beta-Carotene And Retinol Efficacy Trial. Journal of the National Cancer Institute. 1996;88:1550-1559.
 Albanes D, Heinonen OP, Huttunen JK et al. Effects of alpha-tocopherol and beta-carotene supplements on cancer incidence in the Alpha-Tocopherol Beta-Carotene Cancer Prevention Study. American Journal of Clinical Nutrition. 1995;62(6 suppl):1427S-1430S.
 Satia JA, Littman A, Slatore CG, Galanko JA, White E. Long-term use of beta-carotene, retinol, lycopene, and lutein supplements and lung cancer risk: results from the VITamins And Lifestyle (VITAL) study. American Journal of Epidemiology. 2009;169:815-828.
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