Hair turns gray when melanin -- which gives hair its pigment -- is reduced as people get older. Two kinds of melanin determine hair color: eumelanin produces black to brown hair and pheomelanin produces yellow to red hair. Causes of premature graying include stress, illness, excessive drinking of tea, coffee and alcohol and eating too much fried, oily, spicy, sour and acidic foods.
Protein
Eating protein rich foods such as grains, meat and soy aids in the production of melanin. Lack of protein in the body can result in the loss of hair color. The top five grains that are high in proteins are amaranth, buckwheat -- from which flour can be made -- millet, oats and quinoa.
Minerals
Food high in zinc, iron and copper help keep hair healthy. Hair shedding can be caused by a deficiency in zinc. Low amounts of copper in the body can reduce melanin. Sources of zinc are red meat, chicken and green vegetables. Beef, eggs, red meat, wheat and sunflower seeds are good sources of iron. Cashews, almonds, crabs, oysters and egg yolks are good sources of copper.
Vitamins
Vitamin B, found in fresh green leafy vegetables, bananas, tomatoes, wheat germ and yogurt, aids the body in producing sebum, the oily substance in the hair that forms a natural conditioner. You can help prevent gray hair by eating foods rich in Vitamin A, such as dark green vegetables and yellow fruit. Drinking buttermilk with two teaspoons each of yeast and wheatgerm can also aid in keeping your hair its natural color.
Salmon
Salmon is a good source of omega 3 fatty acids. Omega 3s keep the scalp healthy, which is important because a dry scalp can make the color of your hair appear dull. Other sources of Omega 3s are algae, krill, fresh fruits and vegetables and nut oils.
Balanced Diet
Low-calorie diets are usually also low in important hair nutrients. Such eating plans tend to slow hair growth, dull the hair and could also lead to hair loss. Keeping a balanced diet rich in vitamins, minerals and protein should help you keep your natural hair color.