A little vitamin D every day halves your risk of melanoma

Daily intake of a supplement containing extra vitamin D reduces the risk of the most dangerous form of skin cancer by 55 percent. This was discovered by Finnish dermatologists in a study involving 498 visitors to the dermatology clinic at Kuopio University Hospital.

All participants in the study, which appeared in Melanoma Research in April 2023, had in common that they had an increased risk of skin cancer. Some had family members who had developed skin cancer, some had compromised immune systems, some already had spots on their skin that could develop into tumours, and some had skin that had been damaged by excessive sunlight.

When the Finns investigated which lifestyle factors protect this vulnerable group against skin cancer, they discovered that study participants who took a vitamin D supplement every day were more than half as likely to develop melanoma than study participants who did not take vitamin D supplements. If the faithful supplement users did develop melanoma, it was usually less aggressive and easier to treat.

Vitamin D supplements did not protect against forms of skin cancer other than melanoma.

The Finns found no protective effect in the group that took vitamin D supplements irregularly. This group included patients who received high-dose vitamin D supplements from their doctor and took them at intervals of several months.

The effect of vitamin D depends on the method of administration. Skin cells and other cell types contain enzymes that convert vitamin D into protective substances that repair cells and regulate the immune system. If the cells are suddenly supplied with a large amount of vitamin D, the cells switch off these enzymes. This does not happen with daily use of relatively small amounts.

If this is the correct explanation for the research results, it suggests that there is another way to reduce the risk of melanoma: daily exposure of the skin to an optimal amount of ultraviolet light, which stimulates the production of vitamin D in the skin but does not damage the skin cells.

The results of the Finnish study do not come as a complete surprise. According to most scientific studies, the risk of melanoma is lower in people who have healthy vitamin D levels than in people with vitamin D deficiency. Furthermore, people with melanoma have a better prognosis if their vitamin D levels are at the right level than if their vitamin levels are too low.