Gray hair can be the result of a nutritional deficiency such as a lack of vitamins B-12 or B-9. However, it is also a result of the natural aging process -- as you get older, your chances of gray hair increase by 10 to 20 percent every 10 years after the age of 30. Nutrition can help prevent premature graying, but if your hair is changing color as a result of natural aging, there is nothing your diet can do for you.
A lack of vitamin B-12, also known as pernicious anemia, is associated with early graying. Vitamin B-12 helps keep your nervous system healthy and aids in the production of DNA and RNA, as well as working with folic acid, vitamin B-9, to produce red blood cells. The recommended dietary allowance is 2.4 micrograms for most adults, and 2.6 and 2.8 micrograms for pregnant and breast-feeding women, respectively. As you age, your ability to absorb vitamin B-12 from food decreases, so after the age of 50, you should ensure you eat plenty of vitamin B-12-enriched foods. Cereals are frequently fortified with vitamin B-12, and eggs, liver, kidney, fish and shellfish are all good sources of it.
A deficiency in vitamin B-9 can lead to prematurely gray hair. Like vitamin B-12, folic acid helps with the production of DNA and RNA in the body and is necessary for the production of red blood cells. It is also important for the production of methionine, an amino acid that is important for hair color. The RDA of folic acid is 400 micrograms for adults, rising to 600 micrograms for pregnant and 500 micrograms for breast-feeding women. Foods rich in folate, the natural form of folic acid, include spinach, kale, lentils, chickpeas, lima beans, asparagus and cooked rice and pasta. Breakfast cereals are also often enriched with folic acid.
Copper and Iron
A deficiency in copper or iron can increase the chances of premature graying, according to a study published in 2012 in “Biological Trace Element Research.” Researchers found a strong correlation between low copper level and early graying in their test subjects; low iron levels were also evident. Copper is necessary for the healthy function of several essential enzymes in the body, and iron is essential for creating red blood cells. The RDA for copper is 900 to 1,300 micrograms per day for women, and 900 micrograms per day for men. The RDA for iron is 8 milligrams for adults over the age of 50. For women 50 and under, the RDA is 18 milligrams per day. Foods rich in copper include liver, oysters, clams, cashews, hazelnuts, almonds and lentils. Foods rich in iron include beef, spinach and lentils.
Checking for Nutritional Deficiencies
If you think your gray hair is the result of a nutritional deficiency, speak with a medical professional. Low folic acid and vitamin B-12 levels -- as well as low iron and copper levels -- need to be diagnosed with a blood test. Severe nutritional deficiencies require specialized medical care, so before you change your diet or start taking supplements, consult with a doctor. Because genetics and hormones can play a large role in when your hair starts turning gray, early graying may be inevitable if your parents also had gray hair from an early age.