Debate continues as to whether biotin is classified as a vitamin or as one of the B complex vitamins. Biotin was identified in 1940 by Albert Szent-Györgyi, Vincent Du Vigneaud and co-workers. It is water-soluble, crystalline and lacking in colour when isolated. The vitamin is found in liver, kidney, egg yolk, yeast, oats, nuts, milk chocolate and most vegetables. It is also produced naturally by intestinal bacteria, and this normally covers most of our daily requirements. Deficiency may result if a person consumes large quantities of raw egg white. The egg white contains a glycoprotein, called avidin, that forms a complex with biotin that cannot be broken down by the digestive enzymes. This only really occurs if around 20 raw egg whites are consumed per day, and this is fairly uncommon today.
Biotin is an active compound that participates in many enzymatic reactions. It servers as a prosthetic group on the enzyme, which fixes carbon dioxide into an organic compound. This occurs in intermediate compounds in the Krebs cycle, which produces energy from dietary glucose. Biotin is also known as a co-enzyme in the synthesis of fatty acids and purines in the body. Unusually, biotin is also involved in gluconeogenesis, a process in which glucose is produced from non-carbohydrate sources, e.g. amino acids. This occurs only when the diet contains insufficient carbohydrate for energy needs. Biotin also contributes to the production of antibodies and increases the effectiveness of the immune system.
Deficiency of biotin can occur and produces symptoms of loss of appetite, infections of the mucous membranes, depression, insomnia, muscle pains, rashes, discomfort and increased levels of cholesterol in the blood. These problems can be cleared up easily by daily injections of 150-300μg of biotin. Elderly people, athletes and people with epilepsy are known to have relatively low levels of biotin in their blood. Children may be affected by two skin diseases that have been linked to biotin deficiency. Leiner’s disease is a widespread form of seborrhoeic eczema linked to lack of biotin, while the other is a more serious fungoid infection. This infection affects the growth of hair and causes disorders of both the central nervous system and the immune system. This all stems from a malfunction of the carboxylase enzyme, which requires biotin to function effectively, and it is resolved within a few days of biotin supplementation. Fortunately, both diseases are exceedingly rare.μ
Biotin has been tried as part of a therapy to stop hair loss. Combinations of 200-400μg of biotin, para-aminobenzoic acid (PABA), inositol, minerals and essential fatty acids have been tried with variable success.
