Biotin is a vitamin involved in many critically important metabolic processes, a deficiency of which in the newborn can cause serious developmental problems. Given the abundance of sources of biotin in the normal diet, deficiency is not a common situation and is generally caused by a deficiency in biotinidase, an enzyme needed to break the bonds that this vitamin forms with proteins. Biotin, in fact, unlike other vitamins, does not come to be complexed by proteins with merely electrostatic interactions, but forms true chemical bonds with the enzymes for which it plays the role of cofactor. Such bonds are more difficult to break and require the use of a special enzyme to reduce the activation energy and speed up this process.

Clearly, a deficiency or poor function of this enzyme prevents the body from absorbing biotin normally found in foods of animal origin and to recycle that introduced into the body by other means; this impairs the functionality of certain enzymes for which biotin is an essential cofactor: the carboxylases involved in the metabolism of fatty acids, proteins, and carbohydrates. Thus, deficiency in infants and children can be particularly severe, and because of this, biotinidase deficiency is a genetic disorder for which all infants are tested.

In addition to this particular deficiency, there may be other causes leading to this deficiency:

• An intestinal dysbiosis, as this vitamin can be sequestered and absorbed by certain bacteria in the intestinal flora that, if present in excessive amounts, result in failure to be absorbed by the host;
• Alcoholism, as alcohol abuse reduces the intestinal absorption capacity of many micronutrients, including biotin;
• The use of anticonvulsants (barbiturates) or antibiotics
• The intake of raw egg white.

In all these cases, a reduction in biotin absorption may occur because the action of biotinidase is made more difficult (in the case of drugs) or because they contain compounds that bind to biotin with such strong bonds that they cannot be broken even with the help of that enzyme (the proteins in raw egg whites).[1]