Grey Hair and Possible Cancer Protection
Japanese scientists have recently discovered a link between early grey hair and the impact of harmful chemicals and radiation on our bodies. Under the harmful influence of free radical-forming chemicals and radiation, hair in mice turned prematurely grey. This was due to the fast maturing of the affected stem cells in the hair follicles, which made them unable to produce new melanocytes (pigment cells) and thus generate the pigment necessary to give colour to the hair. Instead, stem cells turned themselves into other types of cells in order to inhibit the multiplication of damaged cells.
It is a well known fact that toxic chemicals and ionizing radiation cause cell damage and DNA mutations. This discovery suggests that greying hair can protect our cells from cancer as it inhibits the proliferation of mutated stem cells that might ultimately cause tumors. Besides premature greying, this process can also be used to explain greying in older people, as DNA damage accumulates as we age. Further investigation will be needed to see if this theory is also true of other types of stem cells in our bodies, other than those in hair follicles.