Derek McComiskey asked:
Does stress cause grey hair? Or is it just age? As I am now 50 - this is starting to be relevant.
A young daughter says "Look Mummy, you've got a grey hair". The mother replies "That's because you've been so bad to me". "Gosh Mummy" came the reply "you must have been awful to Grandma!"
Kat Arney put this question to Chris Smith...
Chris - People have looked at this in some detail actually, and thereís not really a consistent story here. Thereís a reason, a clear reason why hair goes grey, or white because the natural colour of hair - it's a protein called keratin. Itís the same protein that makes your fingernails and toenails, and the natural colour of that protein is white. And the reason hair is coloured is, when hair grows out of the hair follicle, which is a little ring of stem cells embedded in your skin that makes the hair, there's another population of cells in the follicle, called melanocytes, and melanocytes, as you probably know - the clue is in the name - make melanin. And there are different flavours of melanin, the chemical. Thereís what we call eumelanin which is a very black colour, and there's feomelanin which is a more yellow colour, and the different ratio of these (the black to the yellow) affects the colour of the hair, and these melanin pigments are added to the hair as it forms, and that give it itís colour. For some reason, as we age, the hair follicle soldiers on but the melanocytes peg out and die, they stop making a colour contribution to the hair and it reverts to its natural state, which is a white colour. Whether or not this can be the consequence of stress, actually, we just donít know. One way that could happen is because, for instance, they become biochemically stressed. Perhaps when you are under periods of extreme stress it could biochemically stress the hair follicles - not really any good evidence for that. Another reason, people have speculated, and itís certainly been animals that thereís a build of hydrogen peroxide at high levels in hair follicles and that hydrogen peroxide can damage the melanocytes. So, perhaps for some reason when youíre stressed you have less ability to defend yourself against hydrogen peroxide attack. But, on the whole, weíre pretty unconvinced, and itís probably genetic because some people keep their hair colour for much longer than others and that tends to run in families. So, it doesnít actually look like Barack Obamaís grey hairs are down to increased stress in the job, itís probably just a lack of Grecian 2000.