Biotin-A water-soluble substance, considered to be part of the B complex vitamins. Biotin is chemically, what we call a dicyclic monocarboxylic acid. Biotin is an essential cofactor for several enzymes (eg., carboxylases), and helps in the metabolism of fatty acids and amino acids.

Sources of biotin

Biotin can be obtained from most foods, especially liver, egg yolk, and milk.

RDA of biotin

Approximately 200 micrograms per day of biotin are sufficient. Since most foods contain biotin, normal UK and US diets are sufficient in supplient the necessary amounts.

Deficiency of biotin

Biotin deficiencies are rare because most foods contain this vitamin. In addition the bacterial gut flora synthesize small amounts, which are absorbed through the intestines. A cause for a biotin deficiency would be starvation. If this were the case, most other vitamins would be deficient as well. Another possible mechanism in developing a biotin deficiency would be to consume large amounts of egg whites. Raw egg whites contain a avidin, a glycoprotein that binds biotin and prevents intestinal absorption. It would take nearly two dozen egg whites per day to achieve this result. Therfore, an egg white on occasion is not harmful. This is something to consider, as there is an in vogue practice of eating raw egg whites as a protein source. This is something that is popular in gyms, where the participant consumes many raw egg whites per day in pursuit of large amounts of protein for increased muscle mass. One must also consider that raw egg whites do not come without their potential risks. The risk of illness through consumption of an infected egg can does exist and many consumers of raw eggs have contracted Salmonella. It is safer to cook the egg white, because much of the protein is still available, and the avidin is denatured if thoroughly cooked.

Biotin deficiency is characterized by dermatitis, glossitis anorexia, nausea and alopecia. This is reversible once biotin levels return to normal.