Vitamin B7 (biotin) deficiency is very rare, and can be measured by several indicators (4, 29, 30, 31).

 

Causes

Deficiency has been shown during prolonged intravenous (‘parenteral’) feeding without vitamin B7 supplementation and consumption of raw egg white for a prolonged period (many weeks to years), since a protein found in raw egg white (avidin) binds biotin and prevents its absorption (11).

 

Research suggests that a substantial number of women develop marginal vitamin B7 deficiency during normal pregnancy (6, 8).

 

Additionally, some types of liver disease may increase the requirement for biotin (32).

 

Furthermore, anticonvulsant medications used to prevent seizures in individuals with epilepsy increase the risk of biotin depletion (10, 33).

 

Symptoms

Signs of overt vitamin B7 (biotin) deficiency include hair loss and a scaly red rash around the eyes, nose, mouth, and genital area. Neurologic symptoms in adults have included depression, lethargy, hallucination, and numbness and tingling of the extremities (11).

 

Individuals with hereditary disorders of biotin metabolism show in addition impaired immune system function and increased susceptibility to bacterial and fungal infections (34).