Two factors determine hair thickness: the thickness of the hair follicles and the number of hair follicles on the scalp. While genetics play a role in hair thickness, the foods you eat also impact the number and size of the hair follicles on your scalp. Several foods contain vitamins and minerals that improve the thickness and overall health of hair.
Legumes contain biotin, a B-complex vitamin necessary for hair growth. While humans rarely have severe biotin deficiencies, diets lacking in biotin result in thinning hair and hair loss. Increase your biotin intake by adding black beans, chickpeas or lentils to soups, salads and chili.
Salmon contains protein and omega-3 fatty acids, essential nutrients for healthy hair. Both of these nutrients encourage hair growth and thickness. Deficiencies in omega-3 fatty acids and protein lead to thin, brittle hair or hair loss. A 4 oz. serving of baked or broiled salmon contains 29.4 g of protein and 2.09 g of omega-3 fatty acids. The omega-3 fatty acid content of salmon represents 87.1 percent of the U.S. recommended daily intake for that nutrient.
Thick hair requires a healthy scalp for continued growth. Carrots contain vitamin A, which keeps the scalp healthy and prevents the hair follicles from thinning. Eat raw carrots as a snack or add shredded carrots to your salad to get more vitamin A on a daily basis.
Nuts contain high levels of protein, along with selenium and omega-3 fatty acids that improve scalp health. One cup of Brazil nuts contains 19.05 g of protein and 2,549.6 mg of selenium, as reported by the U.S. Department of Agriculture. Examples of nuts with omega-3 fatty acids include butternuts, hickory nuts, peanuts and macadamia nuts.
Calcium contributes to hair growth, helping create thicker, fuller hair. Dairy products also contain protein, making them ideal for increasing hair thickness and promoting hair growth. Add dairy products to your diet by drinking milk or eating cheese and yogurt. Even a dish of calcium-packed ice cream helps promote healthier hair.
In addition to high levels of protein, peanut butter also contains zinc. Zinc promotes the hair growth and repair and normalizes the production of oil around the hair follicles. Diets deficient in zinc lead to hair loss, reducing the overall thickness of your hair. Add peanut butter to celery sticks, apple slices or whole-grain bread for a healthful snack that improves your hair's health.