Vitamins may lower risk of melanoma

US researchers found a high dose of retinol supplements, a form of vitamin A, could hold promise as a chemoprotective agent against melanoma.

Experts say more research is needed and that comprehensive sun protection is the best way to reduce the risk of skin cancers.

According to the study, published in the Journal of Investigative Dermatology last night, researchers examined 69,635 men and women to see whether dietary and supplemental vitamin A and carotenoid intake was associated with melanoma risk.

The researchers found that high-dose (41,200 mg per day) supplements of retinol were associated with reduced melanoma risk, particularly among women.

The protective effect was specific to retinol, as higher dietary consumption of related compounds were not associated with a reduction in melanoma risk.

University of Sydney Professor of Medicine and skin cancer expert, Graham Mann, said that the study was not conclusive.

“The main limitation is that they did not assess sun exposure, which is the major risk factor for melanoma,” he said.

“Women who take vitamin supplements may well be better at sun protection, and this could account for the reduced number of melanomas, as the authors acknowledge.”

He said the low rate of skin cancer among study participants could have led to an “entirely chance finding”.

University of Melbourne Dermatology Professor Rod Sinclair said Australian dermatologists had used large dose oral retinoids that mimic vitamin A to prevent skin cancer for “many years”.

“These agents are currently only available on prescription and while much safer than mega-dose vitamin A, they do have significant side-effects.”

Experts also warned about the risks to the fetus of pregnant women taking high dose vitamin A supplements.

Cancer Council SA chief executive Professor Brenda Wilson said SunSmart messages were still the most important way to protect against melanoma but said: “This is very encouraging and we will be interested in further information.”