Sunbathing is known to have its pros and cons, but the debate over whether the benefits of sun exposure outweigh the risks from skin cancer remains constant.

New research by scientists in Norway and the US, published in the Proceedings of the National Academy of Sciences, suggests that the benefit may well outweigh the risks.

The major benefit of the sun's rays on the human body is the production of vitamin D, which occurs in skin cells. This solar-powered vitamin D production is essential for helping the human body protect itself against internal cancers, as well as various neurological, cardiovascular, immune, and bone diseases.

Johan Moan, from the Department of Radiation Biology, Institute for Cancer Research, Oslo, and his colleagues in the US, calculated the average yield of vitamin D in humans depending on their global location.

They found that vitamin D production generated by solar radiation is greater at the equator than in the UK and Scandinavia, and also noted an increase in internal cancers from northern-to-southern latitudes.

While the authors discovered clear latitude gradients of all major forms of skin cancer in populations with similar skin types, they suggest that greater sun exposure may improve the outcomes of many types of cancers. The researchers point out, however, that given the long latency times for cancer, many more decades of analysis are required to determine the impact of anti-sun campaigns on melanoma incidence, cancer prognosis, and other vitamin D deficiency-related diseases.