GREY hair really is a sign of too much stress, according to new research.
When the going gets tough, stem cells that produce colour in hair follicles are damaged, say scientists. Limiting the amount of stress you are under can even stop grey hairs growing.
Too much mental tension changes melanocyte stem cells (MSCs) th
at sit in the follicles and give locks their youthful colour, according to the Japanese scientists.
Researchers have discovered that follicles can suffer the same kind of "genotoxic stress" that does damage to a body's DNA.
Study team leader Emi Nishimura, of Kanazawa University, said: "The DNA in cells is under constant attack by damaging agents such as chemicals, ultraviolet light and radiation.
"It is estimated that a single cell in mammals can encounter approximately 100,000 DNA-damaging events per day."
Mr Nishimura's group traced the loss of hair colour to the gradual dying off of stem cells that ensure a continuous supply of new melanocytes.
Further research on mice has shown that irreparable DNA damage, as caused by radiation, is responsible for greying hair.
The findings support previous research that unstable genes are a significant factor in ageing in general, the researchers said.
Loss of stem cells can also lead to a decline in body-tissue renewal and a speeding-up of other ageing-related characteristics.
The researchers, writing in the science journal Cell, said: "In this study, we discovered that greying hair, the most obvious sign of ageing, can be caused by gene damage through stem cell differentiation."
The full article contains 264 words and appears in The Scotsman newspaper.
