As we age, there are many changes our body undergoes, some of which may seem more distasteful than others. Some age-related changes are more prevalent within certain ethnic groups and also occur at different ages even within those groups. One change that happens to nearly everyone, though at differing times in life, is hair graying or going white. Contrary to many parents’ threats to their children, going gray is not caused by everyday stress.
Hair Anatomy and Color
Hair is constructed with the cuticle on the outside, the cortex in the middle and the medulla on the deepest layer inside the shaft. Melanin is what makes up the color of hair, and is found in the cortex layer. There are two pigments that make up hair color: the dark one is known as eumelanin, and the light one is phaeomelanin. These combine to make up the individual color of a person’s hair.
Aging and Melanin
Hair going gray and possibly eventually completely white as a part of the aging process is called achromotrichia. Though affected by age and genetics, it is thought that the melanocytes that inject color into the hair shafts during growth slow their processes down in the later years. Dr. Desmond Tobin of the University of Bradford in England, suggests that hair follicles have a “melanogenetic clock.” which indicates that the melancocytes are genetically preprogrammed as to when they will stop producing melanin for the hair shaft. When this happens, the hair will become gray due to decreased amounts of the colorant and then eventually completely white when there is a total absence of melanin to color the shaft.
Hydrogen Peroxide
In addition to the reduction of melanin production for hair color as we age, there is also another metabolic function that causes graying. Hydrogen peroxide is known for its bleaching capabilities. Additionally, it is a byproduct of normal cell metabolism processes within our bodies. Professor Heinz Decker, of the Institute of Biophysics at Mainz University, has studied this process along with other researchers. They have found that as we age, the enzyme responsible for breaking down this metabolic byproduct, hydrogen peroxide, cannot keep up, causing a build-up of hydrogen peroxide, which in turn attacks the enzyme that catalyzes the synthesis process of melanin. The end result of this chemical tirade is cessation of melanin production within the hair follicle. The result is a gradual graying all over the head because each individual hair follicle is on its own life cycle. Eventually, the hair totally grays and then turns to white.
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