(HealthDayNews) -- While many fight gray hair with dye, it's just a natural part of aging.
Each hair on your head is made up of a shaft and a root. The root of every strand of hair is surrounded by a tube of tissue called the hair follicle -- and each follicle contains pigment cells. These pigment cells produce a chemical called melanin that gives the growing shaft of hair its color.
As you age, the pigment cells in your hair follicles die. When there are fewer pigment cells, that strand of hair will become gray, silver or white. As people continue to get older, fewer and fewer of these pigment cells will be around to produce melanin, and the hair will eventually look completely gray.
People can get gray hair at any age. How early you get gray hair is determined by your genes as well as poor nutrition, thyroid problems, anemia, and even some diseases such as AIDS and cancer.
But contrary to what some believe, a big shock or trauma can't turn a person's hair gray overnight.