II. Physiology
- Water-soluble B-Vitamin
- Biotin is found in many foods (nuts, whole grains, fruits, vegetables)
- Biotin carries activated CO2 as a Cofactor of carboxylases, involved in multiple enzymatic reactions (e.g. Glucose and Fatty Acid production)
- Oxaloacetate synthesis from pyruvate
- Malonyl-CoA synthesis from acteyl-CoA
- Methylmalonyl CoA synthesis from Propionyl-CoA
- Only small amounts of Biotin are needed
- Recommended daily intake: 30 mcg/day (men and women, including pregnancy)
III. Pathophysiology: Biotin Deficiency
- Biotin deficiency is rare
- Biotin deficiency may manifest as hair thinning
- Risk Factors
- Pregnancy (but Prenatal Vitamins have adequate Biotin)
- Consumption of raw egg whites
IV. Precautions
- No high quality evidence for Biotin supplementation
- Many OTC products contain high dose Biotin (>300 up to 5000 mcg/day)
- High dose Biotin is found in supplements marketed for hair, skin or Nail Growth
- Low dose Biotin (e.g. 30 mcg in Multivitamins)
- High dose Biotin Interferes with lab assays (see below)
- Hold Biotin 3 days before lab testing
V. Labs: High Dose Biotin (>300 mcg/day) falsely LOWERS other lab levels
- Thyroid Stimulating Hormone (TSH)
- Beta-HCG
- Procalcitonin
- Serum Troponin
VI. Labs: High Dose Biotin (>300 mcg/day) falsely RAISES other lab levels
- Serum Free T3
- Serum Free T4
- Serum Folate
VII. References
- (2018) Presc Lett 25(2)
- LoVecchio Crit Dec Emerg Med (2018) 32(5): 32
- Goldberg (2001) Clinical Biochemistry, Medmaster, Miami, p. 43