Human biotin deficiency is extremely rare. This is probably due to the fact that biotin is synthesised by beneficial bacteria in the human intestinal tract. Potential deficiency symptoms include anorexia, nausea, vomiting, glossitis, depression, dry scaly dermatitis, conjunctivitis and ataxia, and after long-lasting, severe biotin deficiency, loss of hair colour and hair loss (alopecia). Signs of biotin deficiency in humans have been demonstrated in volunteers consuming a biotin-deficient diet together with large amounts of raw egg white. After 3-4 weeks they developed a fine dry scaly desquamating dermatitis, frequently around the eyes, nose, and mouth. After ten weeks on the diet, they were fatigued, depressed and sleepy, with nausea and loss of appetite. Muscular pains, hyperesthesia and paresthesia occurred, without reflex changes or other objective signs of neuropathy. Volunteers also developed anaemia and hypercholesterolaemia. Liver biopsies in sudden infant death syndrome babies reveal low biotin levels. Most of the affected infants were bottle-fed.


Groups at risk of deficiency

patients maintained on total parenteral nutrition

people who eat large amounts of raw egg white

haemodialysis patients

diabetes mellitus

individuals receiving some forms of long-term anticonvulsant therapy

individuals with biotinidase deficiency or holocarboxylase synthetase (HCS) deficiency (genetic defects)

patients with malabsorption, including short-gut syndrome

pregnancy may be associated with marginal biotin deficiency