Vitamins are organic substances found in foods and are essential to the body in small quantities for growth, health and preservation of life itself. The body needs vitamins just as it requires other food constituents such as proteins, fats, carbohydrates, minerals and water. The absence of one or more vitamins from the diet, or poor absorption of vitamins, can cause deficiency diseases.

Biotin is essential for carbohydrate metabolism and for the synthesis of fatty acids. It aids in utilization of protein, folic acid, pantothenic acid and vitamin B-12. It is essential for cell growth and replication and is known to promote healthly hair and nails.

In the human body, Biotin is attached at the active site of four important enzymes called carboxylases. Each carboxylase catalyzes an essential metabolic reaction. In short, the four reactions include the synthesis of fatty acids, formation of glucose from amino acids and fats, metabolism of leucine, an essential amino acid and other essential steps in the metabolism of amino acids, cholesterol and fatty acids.

Though rare, Biotin deficiency can cause a wide range of hair, skin and central nervous system abnormalities. Symptoms of deficiency include loss of or thinning of hair, loss of hair color, seborrheic dermatitis, a condition most commonly found in infancy that results in a scaly, itchy red rash commonly located on the scalp, sides of the nose, areas around the eye and behind the ear and central nervous system abnormalities such as depression, fatigue, insomnia, lethargy, hallucinations, and paresthesias.

Marginal states of biotin deficiency may develop during normal pregnancy and in patients taking medications such as anticonvulsants that accelerate the rate of biotin breakdown. It is suggested that women who are pregnant should take extra care to ensure adequate nutrition in their diets. The growing fetus relies solely on the mother for all of its nutrients to survive. Like Folic Acid, which research has proven prevents certain birth defects; Biotin may now be another vitamin women need to supplement before and during pregnancy.

Those individuals who consume raw egg whites may also be at a greater risk of Biotin deficiency. Raw egg whites contain the protein avidin. Avidin binds to Biotin in the intestinal tract preventing absorption. Thus, an abundance of avidin can lead to noticeable symptoms of deficiency including fatigue, weakness, muscle pains and loss of muscle reflexes. This toxic effect of raw egg white was referred to as "egg-white injury". Heat or cooking of the egg white denatures the avidin making biotin available again.

Other conditions affecting adequate Biotin levels include long-term use of Sulfa drugs, antibiotic therapies, prolonged intravenous therapies and deprived diets crammed with junk food.