A deficiency of vitamin A may cause hair to become dull, dry and lusterless and eventually to fall out. Intoxication by heavy metals such as mercury, lead, and cadmium causes hair loss. A well balanced diet is important to maintaining healthy hair, although hereditary graying and balding cannot be completely prevented by nutritional means.

The Truth About Hair Health and Hair Problems Healthy hair is dependent upon blood circulation and quality, which in turn are dependent upon nutrition. A deficiency of protein in diet can result in a temporary change of hair color and texture, resulting in dull, thin, dry hair. Hair is composed primarily of protein. An underactive thyroid causes the hair to fall out. However, an excess of vitamin A may cause similar problems.

Hair loss occurs during stress or when the diet is inadequate in the B vitamins, especially B6, biotin, inositol, and folic acid or in magnesium, sulfur, or zinc. If the protein deficiency is corrected, the hair will return to its normal condition. Excess copper results in hair loss in women who take oral contraceptives and in women in the last months of pregnancy (hair growth will return after birth). Partial lack of any nutrient can cause hair problems.

Graying hair can indicate a deficiency of nutrients in other parts.