What Causes Gray Hair?

Gray hair is a mixture of your natural color and white hairs. Hair color is decided by melanin structure and by genetics. The lessening of melanin production causes grayness; as you age it is almost inevitable that your hair will lose its color or, if your mother or father went white or gray when young, the chances are that you might also.

Although nothing can stop hair from turning gray, there are some conditions that can cause hair to gray earlier or more quickly than normal:

• Thyroid disorders such as Grave's disease, Hashimoto's disease, hyperthyroidism and hypothyroidism have been linked with premature gray hair.

• Vitamin B12 deficiency anemia, which can be due to a diet low in vitamin B12. It can also occur if the stomach can't absorb vitamin B12, due to surgery involving the stomach or small intestine (such as gastric bypass surgery) or diseases that affect the small intestine (such as Crohn's disease, celiac disease and fish tapeworms).

• Vitiligo, a condition in which your skin loses melanocytes, resulting in very light patches of skin and possibly premature gray hair.

• Early menopause.

• Cigarette smoking has been linked to premature gray hair.

Addressing these underlying conditions, in some cases, may help to prevent hair from going premature gray.