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Human beings have many variations in hair color and
texture.
The color of hair varies from pale yellow to deep black. The ethnic distribution of colors has historically varied by
geographic area. For example, deep brown and black prevail in Asia, North Africa, and Mediterranean Europe, and even darker shades occur in tropical Africa and Central America; lighter brown is more common
in central Europe, yellow/blond in northern Europe, and red in the British
Isles.
However, considerable differences in hair color and texture exist between individuals of similar ethnicity, and immigration and global travel have greatly increased the diversity of hair characteristics
in many countries.
Names for human hair colors include:
People also change their hair color to colors that aren't their
natural ones.
Gray, silver, and white hair
A change in hair color also typically occurs naturally as people age, usually turning their hair from its usual color to gray
at first, and then white. The change 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. It is common as people age (more than 40% of Americans have some gray hair by
their fortieth birthday), but can occur as early as the teens and twenties for some. The determination of when someone begins
graying, whether it comes with aging or prematurely, seems to be almost entirely based on genetics.
There are no special diets, nutritional supplements, vitamins, or proteins that have been proven to slow, stop, or in any way
affect the graying process, although many have been marketed over the years.
Many people (reportedly 53%) use hair dye to disguise the amount of gray in
their hair.
A 1996 British
Medical Journal study conducted by J.G. Mosley, MD found that smoking may cause premature graying. Smokers were found to be
four times more likely to begin graying prematurely, compared to nonsmokers in the study. [1]
Medical causes
Vitiligo is a patchy loss of hair and skin color that may occur as the result of
an auto-immune disease.
Werner syndrome and pernicious anemia can also cause premature graying.
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