Grey hair is one of the primary signs of ageing, and approximately 90 percent of us will have grey hair by the time we turn 60. However, greying hair has an upside too. Japanese researchers have discovered that our grey strands appear to be linked to more effective protection against cancer. The grey hairs seem to simply be a by-product of a process where the body eliminates damaged cells that would otherwise
can develop into cancer. The researchers looked at the stem cells in the hair follicles, melanocyte stem cells, which form the pigment that gives hair its colour. When the stem cells are damaged, they can choose between ceasing to function, which means the hair loses its pigment and turns grey, or continuing to divide and risking developing into cancer. The finding thus suggests that grey hair could be the body's way of stopping cells with damaged DNA from continuing to divide and developing cancer.
Source: Nature Cell Biology