1. Biotin deficiency and toxicity
Domina Petric, MD

2. Biotin deficiency I.
November 12, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

3. Introduction
Because biotin is widespread among foods and is synthesized by the intestinal microflora, simple deficiencies of biotin are rare.
Biotin deficiency can be induced by certain antagonists.
November 12, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

4. Clinical deficiency Few cases of biotin deficiency have been reported.
Most of these have involved nursing infants whose mothers’ milk contained inadequate supplies of the vitamin or patients receiving incomplete parenteral nutrition.
November 12, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

5. Clinical deficiency
One case involved a child fed with raw eggs for 6 years.
The signs and symptoms included dermatitis, glossitis, anorexia, nausea, depression, hepatic steatosis and hypercholesterolemia.
The impairments of lipid metabolism respond to biotin therapy.
November 12, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

6. Raw eggs Raw eggs contain AVIDIN.
Avidin antagonizes biotin by forming with the vitamin a noncovalent complex that is resistant to pancreatic proteases, thus preventing the absorption of biotin.
The avidin-biotin complex is unstable to heat.
Heating to at least 100°C denatures the protein and releases biotin available for absorption.
November 12, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

7. Clinical deficiency
Marginal biotin status may play a role in the etiology of sudden infant death syndrome (SIDS), which occurs in human infants at 2-4 months of age.
Studies have shown that infants who died of SIDS had significantly lower hepatic concentrations of biotin than did infants who died of unrelated causes.
November 12, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

8. Subclinical deficiency
Incidence of low circulating biotin levels has been found to be substantially greater among alcoholics than the general population.
Relatively low levels of biotin (versus healthy controls) have also been reported in the plasma or urine of patients with partial gastrectomy or other causes of achlorhydria, burn patients, epileptics, elderly individuals and athletes.
November 12, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

9. Subclinical deficiency
Pregnant women may experience marginal biotin deficiency due to increased catabolism of the vitamin.
November 12, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

10. Biotin toxicity
II.
November 12, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

11. Biotin toxicity The toxicity of biotin appears to be very low.
No cases have been reported of adverse reactions by humans to high levels (doses as high as 200 mg orally or 20 mg iv.) of the vitamin, as are used in treating seborrheic dermatitis in infants or inborn errors of metabolism.
November 12, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

12. Biotin toxicity
Biotin excess appears to provide effective therapy to reduce the diabetic state, lowering postprandial glucose and improving glucose tolerance.
November 12, 2018
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc

13. Literature
Combs GF. The Vitamins. Fundamental Aspects in Nutrition and Health. Elsevier Inc
November 12, 2018