For the most part, when your hair turns grey depends on your genes. If your parents went grey in their 40s, odds are you will, too. In some cases, though, external factors can make your hair turn grey prematurely. Your hair gets its color from the pigment melanin. When the body stops making melanin or when melanocytes — the cells that bring the pigment to hair and skin cells — die, your hair begins to grey. While you can’t change your genes, you can change your habits that put you at risk for grey hair.
Take Your Vitamins
Make sure you are getting enough of vitamin B-12. You need B-12 to make red blood cells. A deficiency can lead to prematurely grey hair, even in children, according to Dr. Alan Greene. The vitamin is only found in animal based foods, such as meat and dairy, so you may not get enough if you eat a vegan diet. Although it’s rare, pernicious anemia is a condition that prevents your body from properly absorbing B-12. Talk to your doctor about B-12 injections if you think you may be deficient.
Smoking cigarettes ages your entire body prematurely and has been shown to cause grey hair, according to a study performed by doctors J.G. Mosley and A.C.C. Gibbs, as published in "British Medical Journal" in 1996.
Test Your Thyroid
According to Womenshealth.gov, hyperthyroidism or hypothyroidism can cause your hair to turn grey before its time. You should definitely get checked for a thyroid condition if a family member had this disorder or went grey early.
Increase the amount of copper in your diet to stop the appearance of grey hair. Copper helps form the enzyme tyrosinase, which plays an important role in the formation of pigment, or melanin, according to the Linus Pauling Institute. Beef liver and oysters are a great source of copper, as are nuts and chocolate.