Skin cancers have a higher incidence than all other cancers combined and are a major cause of morbidity worldwide. Laboratory data suggest certain dietary constituents, notably omega-3 polyunsaturated fatty acids (n-3 PUFAs), could potentially protect against skin malignancy, although no large-scale review has been conducted in humans. The objective of this review and meta-analysis was to determine the relationship between dietary n-3 PUFAs and skin cancer incidence. It considered all published randomized controlled trials and observational studies up to March 2013. Five studies (two case–control and three cohort) were identified pertaining to oral n-3 PUFA consumption and incidence of basal cell carcinoma (BCC), squamous cell carcinoma (SCC), melanoma (or a combination) and were included in a random-effects meta-analysis. A further six studies considering nondietary n-3 PUFA exposure (e.g. by tissue analysis) and/or recognized biological markers of skin cancer risk (e.g. p53 expression) were analyzed qualitatively. Dietary n-3 PUFAs were not associated with BCC (pooled OR 1.05, 95% CIs 0.86–1.28). Consumption of high levels of n-3 PUFAs were inversely associated with melanoma, although with only one estimate available (OR 0.52, 95% CI 0.34–0.78), and SCC, although nonsignificantly (pooled OR 0.86, 95% CIs 0.59–1.23). Available evidence is suggestive, but currently inadequate, to support the hypothesis that n-3 PUFAs protect against skin malignancy.What's new?
Current strategies in the prevention of skin cancers remain limited, although experimental studies suggest that diet, specifically omega-3 polyunsaturated fatty acids (n-3 PUFAs), may modulate carcinogenesis. This systematic review and meta-analysis indicates, however, that no association exists between dietary n-3 PUFAs and basal cell carcinoma. Furthermore, while the data suggests that n-3 PUFAs may be inversely associated with melanoma and squamous cell carcinoma, the relationships either are based on scant data or are nonsignificant. The results indicate that existing evidence is inadequate to support the hypothesis that n-3 PUFAs protect against skin malignancy.