Skin cancer prevention and UV-protection: how to avoid vitamin D-deficiency?

Because solar UV-radiation represents the most important environmental risk factor for the development of non-melanoma skin cancer, UV protection is important to prevent these malignancies. Consequently, public health campaigns were developed to improve the knowledge of the general population regarding the role of UV-radiation for the development of skin cancer. However, it has to be noted that vitamin D-mediated positive effects of UV light were not adequately considered in most of these campaigns, that often propose a strict 'no sun policy' without giving recommendations how to prevent vitamin D-deficiency. Under our living conditions, approximately 90% of all vitamin D needed by the human body has to be formed in the skin through the action of UV-B-radiation and it has been shown that strict sun protection causes vitamin D-deficiency. This dilemma represents a serious problem, for an association of vitamin D-deficiency and multiple independent diseases including various types of cancer, bone diseases, autoimmune diseases, infectious diseases, cardiovascular diseases and hypertension has now been reported in a large number of laboratory and epidemiologic investigations. Although further work is necessary to define an adequate vitamin D-status and adequate guidelines for UV-exposure, it is at present mandatory that guidelines for UV-exposure (e.g. in skin cancer prevention campaigns) consider these facts and give recommendations how to prevent vitamin D-deficiency. At present, most experts in the field agree that the evidence to date suggests that daily intake of 1000-2000 IU vitamin D could reduce the incidence of vitamin D-deficiency-related diseases with minimal risk in Europe, the US, and other countries. In this review, we analyze the present literature to help developing well-balanced guidelines on UV-protection that ensure an adequate vitamin D-status. These recommendations will hopefully protect us against vitamin D-deficiency without increasing the risk to develop UV-induced skin cancer.