A study published in the January 2003 issue of the International Journal of Cancer reported that dietary antioxidants do not appear to reduce the risk of developing squamous cell skin cancer.
Ultraviolet B (UBV) radiation from sun exposure is the most common environmental factor linked to the development of squamous cell skin cancer. One of the hypotheses is that exposure to UVB radiation leads to the depletion of antioxidants in the skin. Several vitamins contain antioxidants and may potentially reduce the adverse effects of sun exposure on the skin. Antioxidants protect against the deterioration of healthy cells induced by free radicals or cancer-causing agents, such as UBV radiation. It has been demonstrated that the combined use of beta-carotene (an antioxidant found in carrots and other orange/reddish vegetables like tomatoes) with vitamins C and E decreases reactive oxygen radicals caused by UBV and reduces sunburn reactions. This had led some researchers to suggest that a high intake of antioxidant vitamins could lead to a lower incidence of squamous cell skin cancer. However, there have been few clinical trials to test this hypothesis.
Researchers at Harvard Medical Center recently performed a clinical study determining the effects of antioxidants on the incidence of skin cancer. The population studied included nurses and health care workers participating in a long-term study that started in 1982. This study included 85,944 women and 43,867 men, of whom 674 developed squamous cell skin cancer. The researchers looked at the intake of vitamins A, C and E, as well as folic acid and various carotenes.
The researchers did not find any correlation between the amount of antioxidants taken and the incidence of squamous cell skin cancer, leading them to conclude that there is no evidence “ that vitamins A, C and E; folate; or carotenoids play an important protective role” against the development of squamous cell skin cancer. However, this study only looked at dietary sources of these substances and not at “therapeutic” doses of anti-oxidants; it is still possible that higher doses of antioxidants could have a preventive effect. Nonetheless, reduced sun exposure still appears to be the best protection against this type of cancer.
Reference: Fung T, Spiegelman D, Egan K, et al. Vitamin and carotenoid intake and risk of squamous cell carcinoma of the skin.
International Journal of Cancer. 2003;103:110-115.