Why Hair Goes Gray

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[coverattach=1]Study Blames a Chain Reaction That Makes Hair Bleach Itself From the Inside Out
By Miranda Hitti

Have you ever watched someone try to cover up gray hair by dyeing it? Or maybe you wonder why your granddad has a full head of silver hair when in old pictures it used to be dark brown?

Gray hair seems to be every woman's nightmare. But it is a completely natural and normal process, a natural part of growing older.

Here's why

As we now know, our hair goes through three main phases of growth. We begin with an active growing phase for 2-5 years. Our hair rests for 100 days and sheds. Then, the process begins all over again.

Each hair on our heads is made up of two parts:
a shaft - the colored part we see growing out of our heads
a root - the bottom part, which keeps the hair anchored under the scalp

The root of every strand of hair is surrounded by a tube of tissue under the skin that is called the hair follicle (say: fah-lih-kul). Each hair follicle contains a certain number of pigment cells. These pigment cells continuously produce a chemical called melanin (say: meh-luh-nin) that gives the growing shaft of hair its color of brown, blonde, red, and anything in between.

Melanin is the same stuff that makes our skin's color fair or darker. It also helps determine whether a person will burn or tan in the sun. The dark or light color of someone's hair depends on how much melanin each hair contains.

As we get older, the pigment cells in our hair follicles gradually die. When there are fewer pigment cells in a hair follicle, that strand of hair will no longer contain as much melanin and will become a more transparent color - like gray, silver, or white - as it grows. As people continue to get older, fewer pigment cells will be around to produce melanin. Eventually, the hair will look completely gray.

People can get gray hair at any age. Some people go gray at a young age - as early as when they are in high school or college - whereas others may be in their 30s or 40s before they see that first gray hair. How early we get gray hair is determined by our genes. This means that most of us will start having gray hairs around the same age that our parents or grandparents first did.

Gray hair is more noticeable in people with darker hair because it stands out, but people with naturally lighter hair are just as likely to go gray. From the time a person notices a few gray hairs, it may take more than 10 years for all of that person's hair to turn gray.

Some people think that a big shock or trauma can turn a person's hair white or gray overnight, but scientists don't really believe that this happens. Just in case, try not to freak out your parents too much. You don't want to be blamed for any of their gray hairs!

Causes

Scientists may have figured out what causes hair turns gray, and their finding may open the door to new anti-graying strategies. According to the FASEB Journal, Scientists may have figured out why hair turns gray, and their finding may open the door to new anti-graying strategies.

New research shows that hair turns gray as a result of a chemical chain reaction that causes hair to bleach itself from the inside out.

The process starts when there is a dip in levels of an enzyme called catalase. That catalase shortfall means that the hydrogen peroxide that naturally occurs in hair can't be broken down. So hydrogen peroxide builds up in the hair, and because other enzymes that would repair hydrogen peroxide's damage are also in short supply due to wear and tear of hair follicles, the hair goes gray.

The build-up of peroxide eventually blocks our normal synthesis of melanin, the natural pigment responsible for our hair, skin, and eye colour.

Hair follicles cannot repair the hydrogen peroxide damage, which is also complicated by an enzyme being disrupted that leads to melanin production in hair follicles.

Putting the brakes on that chemical chain reaction "could have great implications in the hair graying scenario in humans," write the researchers, who included Karin Schallreuter, a professor clinical and experimental dermatology at England's University of Bradford.

The study appears online in The FASEB Journal; the FASEB is the Federation of American Societies for Experimental Biology.

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The process starts when there is a dip in levels of an enzyme called catalase. That catalase shortfall means that the hydrogen peroxide that naturally occurs in hair can't be broken down. So hydrogen peroxide builds up in the hair, and because other enzymes that would repair hydrogen peroxide's damage are also in short supply, the hair goes gray.
Putting the brakes on that chemical chain reaction "could have great implications in the hair graying scenario in humans," write the researchers, who included Karin Schallreuter, a professor clinical and experimental dermatology at England's University of Bradford.