Does vitamin B3 prevent skin cancer?
Greg, a 75-year-old Anglo-Australian retiree, presented with a nodular basal cell carcinoma on his shoulder, which I excised.
Greg had been an avid surfer in his youth — a lot of sun exposure with no sunscreen.
Afterwards, I read in an online GP discussion forum that oral vitamin B3 (nicotinamide) might prevent further skin cancers in people like Greg.
What is the evidence?
What is the effect of nicotinamide, used as preventive therapy, on the incidence of skin cancers?