Results of a large prospective cohort study have shown that antioxidant supplements do not appear to be associated with an increased risk of skin cancer (melanoma), which has been suggested by an earlier randomized controlled trial.
In 2007, a randomized trial of antioxidants for cancer prevention (SUVIMAX) indicated that daily supplementation with nutritionally appropriate doses of vitamin C, vitamin E, beta-carotene, selenium and zinc appeared to increase the risk of melanoma in women fourfold (1). Because an estimated 48–55% of US adults use vitamin or mineral supplements regularly, the potential harmful effects of these nutrients is alarming, the authors noted.
In the new study, Maryam M. Asgari and colleagues examined the association between antioxidants and melanoma among 69,671 women and men who were participating in the Vitamins and Lifestyle (VITAL) study, designed to examine supplement use and cancer risk (2). Intake of multivitamins and beta-carotene supplements during the previous 10 years was not associated with melanoma risk in either women or men. The researchers also examined the risk of melanoma associated with long-term use of supplemental beta carotene and selenium at doses comparable to the previous study and found no association.
The researchers commented that the earlier association between the SUVIMAX supplement and melanoma risk in women could be explained by methodological shortcomings: the analysis was limited to a subsample of participants who agreed to answer only a single question on their lifetime sun exposure ("How would you describe the intensity of your skin's exposure to the sun during your lifetime?"), which could introduce selection bias and limit generalizability.