The Relationship Between Dietary Factors and Skin Cancer Development: Clinical Relevance

Globally, skin cancer accounts for more than all other malignancies combined. Skin cancer imposes a significant financial and societal burden. UVR exposure is responsible for 90% of skin cancer and is a major source of exogenous free radicals. The free radical theory of aging and cancer led to the investigation of polyunsaturated lipids, antioxidants (including synthetic phenols, polyphenols, flavonoids) and ß-carotene as potential modulators of UVR-carcinogenesis. Experimentally, both dietary lipids and antioxidants modified the tumor latent period and multiplicity. Increasing levels of omega-6 fatty acids exacerbated UVR-carcinogenesis in a near linear fashion. However, omega-3 fatty acid inhibited UVR-carcinogenesis. Both types of lipids exhibit the same level of saturation. Thus, the inhibition of UVR-carcinogenesis by omega-3 fatty acid must rest with differential metabolic intermediates that each generate, both tumor-promoting and immune-modulating. Clinically, a low-fat dietary intervention trial has shown that reduced fat intake significantly reduces the occurrence of nonmelanoma skin cancer. Dietary supplementation of antioxidants and ß-carotene into the complex milieu of the cell with its own intricate and complex free radical defense system has resulted in detrimental responses and antioxidant dietary supplements, as well as ß-carotene, are no longer recommended for the public as a mean to prevent cancer.