BIOTIN (ALSO KNOWN AS VITAMIN B7)

Biotin, also known as vitamin B7, is one of the eight B-complex vitamins. Biotin cannot be manufactured by humans and is thus a true vitamin, obtained exclusively from the diet.

Biotin is an enzyme cofactor, which means that it is a necessary component for enzyme function. Biotin is the cofactor for several carboxylase enzymes that are important for metabolism, specifically involving in fatty acid synthesis, branched-chain amino acid catabolism, and gluconeogenesis.

Biotin deficiency can develop in certain conditions, especially in severe gastrointestinal disease, or with the consumption over time of large quantities of raw egg white. Findings of biotin deficiency can include mental health-related issues such as depression, lethargy, and psychosis, as well as numbness and tingling of the extremities. Biotin deficiency can also cause abnormalities to the skin (rash), mucous membranes (eye redness), hair (loss), and nails (brittle).

The role of biotin in the treatment of autism is not well studied. Children with ASD often have diets that are relatively deficient in many nutrients, and low levels of biotin in blood have been observed in children with ASD (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3135510/pdf/1743-7075-8-34.pdf). In one study, 12 out of 187 ASD patients (7%) revealed increased urine levels of 3-hydroxyisovaleric acid (a biochemical sign consistent with biotin deficiency), and 7 of those 12 had “minor to significant improvement in autistic features” following biotin supplementation (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3871708). Severe biotin deficiency occurs with biotinidase deficiency, a metabolic disorder involving biotin recycling, and ASD has been reported in this condition (https://www.ncbi.nlm.nih.gov/pubmed/13680408?dopt=Abstract; http://www.epilepsybehavior.com/article/S1525-5050(14)00412-0/pdf).

Biotin is often taken for the health of the skin, hair, and nails. Other situations for which biotin is sometimes recommended include diabetes, depression, and pregnancy, the latter of which low biotin levels are often identified.

Biotin is a water-soluble vitamin and thus considered to be generally non-toxic. Doses as high as 10 mg a day are frequently given in infants and children with biotinidase deficiency. Side effects are rare even at these extremely high doses.

Laboratory testing can reveal the presence of a deficiency of this nutrient, but is generally not likely to have clinically utility.