Many people spend a lot of money on expensive shampoos and salon treatments for their hair, but your diet is the true indicator of how healthy your hair is. Diets that are poor in certain vitamins, iron, or protein will affect the appearance of your hair. Problems with your hair or scalp such as slow hair growth, thinning hair, split ends, brittleness or breakage, dandruff or redness necessitate change in your diet to allow your hair to heal and stay healthy.

If you suffer from ever-present split ends, consider adding more protein to your diet. Soy milk is packed with protein, as are chicken and turkey breasts, salmon, tofu, eggs, and soybeans. Try increasing your intake of these foods in your diet to help cure and decrease your split ends.

Brittle hair or hair that tends to break easily is indicative of a low fat diet along with high levels of stress in your life, and maybe some dehydration. You should include foods high in oils and monounsaturated and polyunsaturated fats such as avocados and salmon. Cooking with olive oil or sunflower oil instead of vegetable oil will help increase oil and healthy fat consumption. Walnuts and sunflower seeds are good choices for snacks.

Thinning hair can be an indicator of insufficient iron levels in the body. In fact, iron deficiency is the second leading cause of hair loss. Thinning hair can also be a sign of premenopausal symptoms and a resulting drop in estrogen levels. Foods high in oils, such as walnuts, can help replenish the hair's elasticity and will help treat thinning hair. Spinach and bok choy are rich in iron, minerals, and vitamins, all of which help to keep the scalp and natural scalp oils healthy. Also, try eating halibut and other fish that are rich in magnesium, which helps with hair growth. Low fat Greek yogurt has vitamins B5 and D, which are essential to hair health. Vitamin A, found in carrots and sweet potatoes in the form of beta carotene, and vitamin D, found in eggs and fortified milk, are also beneficial to hair.

Slow hair growth can indicate deficiencies in vitamins B and C, and the minerals iron zinc. It can also be a symptom of health issues, such as a thyroid problem. After eliminating any possible health reasons for slow hair growth, be sure to include enough protein in your diet. If the body doesn't get enough protein, your hair will grow more slowly. Oysters, crabs, clams, and lean beef are high in zinc, and dark greens like spinach and broccoli are high in iron and vitamins A and C.

Dandruff or redness on the scalp can also be signs of poor diet. Eating too many fat and sugars over a short period of time can cause a red itchy scalp, while a deficiency in oils and healthy fats can cause dryness. Olive oil, walnuts, salmon, and other foods high in omega-3 fatty acids will help keep the scalp and hair follicles moisturized.