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Hair Color
Hair color is the result of pigmentation due to the presence of the chemicals melanin and pheomelanin.
Human beings have many variations in hair color and hair texture. In general, the more melanin present, the darker the hair color; the less melanin, the lighter the hair color. Usually the color of children's and adults' hair varies from pale yellow (blond) to deep black. An individual may have hair of more than one color at a time. A person's hair color may also change over time.
Aging and Hair Color
A change in hair color typically occurs naturally as people age, usually turning their hair from its natural color to gray and then to white. More than 40 percent of Americans have some gray hair by their fortieth birthday, but white hairs can appear as early as childhood. The age at which graying begins seems to be almost entirely based on genetics. Sometimes people are born with gray hair because it is passed down genetically. Many people use hair dye to disguise the amount of gray in their hair.
The change in hair color is caused by the gradual decrease of pigmentation that occurs when melanin ceases to be produced in the hair root and new hairs grow in without pigment. Two genes appear to be responsible for the process of graying, Bcl2 and Mitf. The stem cells at the base of hair follicles are responsible for producing melanocytes, the cells that produce and store pigment in hair and skin. The death of the melanocyte stem cells causes the onset of graying.
Artificial Factors And Hair Color
A 1996 British Medical Journal study conducted by J.G. Mosley, MD found that tobacco smoking may cause premature graying. Smokers were found to be four times more likely to begin graying prematurely, compared to nonsmokers in the study. Gray hair may temporarily darken after inflammatory processes, after electron-beam-induced alopecia, and after some chemotherapy regimens. Much remains to be learned about the physiology of human greying.
There are no special diets, nutritional supplements, vitamins, nor proteins that have been proven to slow, stop, or in any way affect the graying process, although many have been marketed over the years. This may change in the near future. French scientists treating leukemia patients with a new cancer drug noted an unexpected side effect: some of the patients' hair color was restored to their pre-gray color.
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