Genetics and health are factors in healthy hair. Proper nutrition is important for hair health. The living part of hair is under the scalp skin where the hair root is housed in the hair follicle. The entire follicle and root are fed by a vein, and blood carries nutrients to the follicle/root. Any time an individual has any kind of health concern from stress, trauma, medications of various sorts, chronic medical conditions or medical conditions that come and then wane, heavy metals in waters and food, smoking etc. these and more can affect the hair, its growth, and its appearance.
Generally, eating a full diet that contains protein, fruits, vegetables, grains, and even an appropriate amount of fat is important (several vitamins and minerals require fat in order to be delivered or absorbed by the body). Any deficiency will typically show first in the hair. A mild case of anemia can cause shedding and hair loss. Among others, the B group of vitamins are the most important for healthy hair, especially biotin. B5 (pantothenic Acid) gives hair flexibility, strength and shine and helps prevent hair loss and graying. B6 helps prevent dandruff and can be found in cereals, egg yolk and liver. Vitamin B12 helps prevent the loss of hair and can be found in fish, eggs, chicken and milk.
When the body is under strain, it reprioritizes its processes. For example, the vital organs will be attended to first, meaning that healthy, oxygenated blood may not feed into the hair follicle, resulting in less healthy hair or a decline in growth rate. While not all hair growth issues stem from malnutrition, it is a valuable symptom in diagnosis.
Scalp hair grows, on average, at a rate of about half an inch per month, and shampoos or vitamins have not been shown to noticeably change this rate. Hair growth rate also depends upon what phase in the cycle of hair growth one is actually in; there are three phases. The speed of hair growth varies based upon genetics, gender, age, hormones, and may be reduced by nutrient deficiency (i.e., anorexia, anemia, zinc deficiency) and hormonal fluctuations (i.e., menopause, polycystic ovaries, thyroid disease).
The essential omega-3 fatty acids, protein, vitamin B12, and iron, found in fish sources, prevent a dry scalp and dull hair color. Dark green vegetables contain high amounts of vitamins A and C, which help with production of sebum and provide a natural hair conditioner. Legumes provide protein to promote hair growth and also contain iron, zinc, and biotin. Biotin functions to activate certain enzymes that aid in metabolism of carbon dioxide as well as protein, fats, and carbohydrates. A deficiency in biotin intake can cause brittle hair and can lead to hair loss. In order to avoid a deficiency, individuals can find sources of biotin in cereal-grain products, liver, egg yolk, soy flour, and yeast. Nuts contain high sources of selenium and therefore are important for a healthy scalp. Alpha-linoleic acid and zinc are also found in some nuts and help condition the hair and prevent hair shedding that can be caused by a lack of zinc. Protein deficiencies or low-quality protein can produce weak and brittle hair, and can eventually result in loss of hair color. Low-fat dairy products are good sources of calcium, a key component for hair growth. A balanced diet is extremely necessary for a healthy scalp and furthermore healthy hair.