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Hair color is the result of pigmentation due to the presence of the chemicals of melanin. In general, the more melanin, the darker the hair color.
In general, the color of children's and adults' 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 reddish 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 brun|brun
People also change their hair color to colors that aren't their natural ones.
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 geneticsGenetics is the science of genes, heredity, and the variation of organisms. Humans began applying knowledge of genetics in prehistory with the domestication and breeding of plants and animals. In modern research, genetics provides important tools in the i.
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 19961996 was a leap year starting on Monday (see link for calendar), and was designated the International Year for the Eradication of Poverty''. Events January January 5 Hamas operative Yahya Ayyash is killed by an Israeli-planted booby-trapped cell phone Jan British Medical JournalThe British Medical Journal (BMJ) is a medical journal published weekly in the United Kingdom by the British Medical Association (BMA). Its editor-in-chief is Richard Smith. External links Medical journals. 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]