Biotin

Overview

Biotin is one of the more recently discovered water-soluble B vitamins. It was first isolated in 1936, the structure was identified in 1942, and synthesized in 1943. Biotin is essential for the activity of many enzyme systems.

Dosage Info

Dosage Range

30-5,000mcg daily

Most Common Dosage

900mcg daily

Dosage Forms

Tablets and capsules.

Adult RDI

300mcg

Adult ODA

None established

RDA

• Infants < 6 months: 5mcg (Adequate Intake, AI)
• Infants 7-12 months: 6mcg (AI)
• Children 1-3 years: 8mcg (AI)
• Children 4-8 years: 12mcg (AI)
• Children 9-13 years: 20mcg (AI)
• Children 14-18 years: 25mcg (AI)
• Adults >19 years: 30mcg (AI)
• Pregnancy: 30mcg (AI)
• Lactation: 35mcg (AI)

Interactions and Depletions

Depletions

• Antibiotics
• Anticonvulsants

Active Forms

Biotin.

Absorption

Biotin absorption takes place in the proximal small intestine. Dietary biotin, which is protein-bound, must be acted upon by intestinal enzymes in order to liberate free biotin for absorption. Some biotin is also absorbed from the distal small intestine where it is biosynthesized by the normal flora in the intestine.

Toxicities & Precautions

General

There are no known toxicities associated with biotin. Excess is eliminated via the urine.

Functions in the Body

Energy Production

Plays a vital role in the production of energy from the metabolism of carbohydrates and fats.

Fat/Protein Metabolism

Involved in the manufacture of fats and the excretion of byproducts from protein metabolism.

Participate in:

carboxylation reactions (adding CO₂ to acceptor molecules)

decarboxylation reactions where CO₂ groups are removed

deamination reactions where NH₂ groups are removed from certain amino acids.

Hair

Known as the vitamin that produces healthy hair and helps prevent graying. Supplementation in cases of severe deficiency can help, but successful treatment usually requires administration of all B vitamins and lipotropics in order to correct underlying fatty-acid metabolic problems. However, biotin does help with “uncombable hair syndrome,” a condition in children with multiple cowlicks where hair sticks up in all directions and won’t lie down.

Clinical Applications

Brittle Nails

63 percent of patients gained up to a 25 percent increase in nail thickness. (1)

Diabetic Peripheral Neuropathy

Biotin-dependent enzyme, pyruvate carboxylase, influences nervous system metabolism. (2)

Sids

Liver biopsies in sudden infant death syndrome babies reveal low biotin levels. (3)

Diabetes Mellitus

Biotin is needed to metabolize glucose (4) and lower blood sugar levels. (5)

Seborrheic Dermatitis

Seborrheic dermatitis results from biotin deficiency, especially in infants. (6) , (7)

Uncomable Hair Syndrome

Uncomable hair syndrome in children – responds to biotin supplementation. (8)

Symptoms and Causes of Deficiency

Biotin deficiency in humans is very rare. This is probably due to the fact that biotin is synthesized by beneficial bacteria in the human GI tract.

Some patients with diabetes may have an abnormality in the biotin-dependent enzyme pyruvate carboxylase, which can lead to dysfunction of the nervous system.

A deficiency can result from ingestion of large amounts of raw egg whites, which contain a protein called avidin that strongly binds with biotin.

Although deficiency is rare, potential symptoms include: hair loss, loss of hair color, depression, scaly dermatitis, lesions on the nose and mouth, anorexia, nausea, numbness and tingling of the extremities, muscle pain, and cardiac irregularities.

Dietary Sources

Biotin is found abundantly in many plant and animal foods. A considerable amount of biotin is also synthesized by the beneficial intestinal bacteria. Best food sources include liver, milk, brewer’s yeast, bananas, grapefruit, watermelon, strawberries, and peanuts.

References

1. View Abstract: Hochman LG, et al. Brittle Nails: Response to Daily Biotin Supplementation. Cutis. Apr1993;51(4): 303-05.
2. View Abstract: Koutsikos D, et al. Biotin for Diabetic Peripheral Neuropathy. Biomed Pharmacother. 1990;44(10):511-14.
3. View Abstract: Johnson AR, et al. Biotin and the Sudden Infant Death Syndrome. Nature. May1980;285(5761):159-60.
4. View Abstract: Koutsikos D, et al. Oral Glucose Tolerance Test after High-dose I.V. Biotin Administration in Normoglucemic Hemodialysis Patients. Ren Fail. Jan1996;18(1):131-37.
5. Maebashi M, et al. Therapeutic Evaluation of the Effect of Biotin on Hyperglycemia in Patients with Non-insulin Dependent Diabetes Mellitus. J Clin Biochem Nutr. 1983;14:211-18.
6. View Abstract: Bonjour JP. Biotin in Man’s Nutrition and Therapy – A Reivew. Int J Vitam Nutr Res. 1977;47(2):107-18.
7. View Abstract: Schulpis KH, et al. The effect of isotretinoin on biotinidase activity. Skin Pharmacol Appl Skin Physiol. Jan1999;12(1-2):28-33.
8. View Abstract: Shelley WB, et al. Uncombable Hair Syndrome: Observations on Response to Biotin and Occurrence in Siblings with Ectodermal Dysplasia. J Am Acad Dermatol. Jul1985;13(1):97-102.