…Its enough to turn you grey
UK and German researchers have now unlocked the secret of hair turning white or gray in old age. According to them, free oxygen radicals are to blame for those pesky greys.
UK and German researchers have now unlocked the secret of hair turning white or gray in old age. According to them, free oxygen radicals are to blame for those pesky greys.
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| Scene of the crime – excess H2O2 halts the production of melanin in the hair follicle |
Hydrogen peroxide (H2O2) is a by-product of metabolism and is generated in small amounts throughout the human body - including hair follicles. With increasing age, the quantity builds up, because the human body can no longer keep up neutralizing the hydrogen peroxide. In their work, the team showed that in aging cells the enzyme used to break down H2O2 is only present in very limited concentration.
This has dramatic consequences. Hydrogen peroxide attacks the enzyme tyrosinase by oxidizing an amino acid - methionine. As a consequence, this key enzyme - which normally starts the synthesizing pathway of the coloring pigment melanin - does not function anymore.
Oxidation by hydrogen peroxide not only interferes with the production of melanin, but also inhibits other enzymes that are needed for the repair of damaged proteins. As a result, a cascade of events is set off, at the end of which stands the gradual loss of pigments in the entire hair from its root to its tip. With this research work, the scientists from Mainz and Bradford not only solved – on a molecular level – the age-old riddle of why hair turns gray in old age, but also have pointed out approaches for future therapy of vitiligo, a skin pigment disorder. For melanin is not only the pigment in hair, but it is also responsible for color in skin and eyes.
