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Biotin, a water-soluble B vitamin, acts as a coenzyme in the metabolism of protein, fats, and carbohydrates.
Where is it found? Good dietary sources of biotin include organ meats, oatmeal, egg yolk, soy, mushrooms, bananas, peanuts, and brewers yeast. Bacteria in the intestine also produce significant amounts of biotin, but evidence is conflicting as to whether biotin produced by intestinal bacteria is present at a location or is in a form that permits significant absorption by the body.1
Biotin has been used in connection with the following conditions (refer to the individual health concern for complete information):
Who is likely to be deficient? Certain rare inborn diseases can leave people with depletion of biotin due to the inability to metabolize the vitamin normally. A dietary deficiency of biotin, however, is quite uncommon, even in those consuming a diet low in this B vitamin. Nonetheless, if someone eats large quantities of raw egg whites, a biotin deficiency can develop, because a protein in the raw egg white inhibits the absorption of biotin. Cooked eggs do not present this problem. Long-term antibiotic use can interfere with biotin production in the intestine and increase the risk of deficiency symptoms, such as dermatitis, depression, hair loss,2 anemia, and nausea. Long-term use of anti-seizure medications may also lead to biotin deficiency.3 Alcoholics, people with inflammatory bowel disease, and those with diseases of the stomach have been reported to show evidence of poor biotin status. However, the usefulness of biotin supplementation for these people remains unclear.4 In animals, and possibly in humans, biotin deficiency can cause birth defects.5
How much is usually taken? The ideal intake of biotin is unknown. However, the amount of biotin found in most diets, combined with intestinal production, appears to be adequate for preventing deficiency symptoms. Researchers have estimated that 30 mcg per day appears to be an adequate intake for adults.6 Typically, consumption from a Western diet has been estimated to be 30-70 mcg per day. Larger amounts of biotin (8-16 mg per day) may be supportive for people with diabetes by lowering blood glucose levels and by preventing diabetic neuropathy.7 8 Biotin in the amount of 2.5 mg per day strengthened the fingernails of two-thirds of a group of people with brittle nails, according to one clinical trial.9
Are there any side effects or interactions? Excess intake of biotin is excreted in the urine; no toxicity symptoms have been reported.
Biotin works with some other B vitamins, such as folic acid, pantothenic acid (vitamin B5), and vitamin B12. However, no solid evidence indicates that people supplementing with biotin also need to take these other vitamins. Symptoms of pantothenic acid or zinc deficiency have been reported to be lessened with biotin,10 though people with these deficiencies should supplement with the nutrients in which they are deficient. Researchers have speculated that biotin and alpha lipoic acid may compete with each other for absorption or uptake into cells; but little is known about the importance of these interactions in humans.11
Are there any drug interactions? Certain medications may interact with biotin. Refer to the drug interactions safety check for a list of those medications.
1. Mock DM. Biotin. In: Shils ME, Olson JA, Shike M, Ross, AC (eds). Modern Nutrition in Health and Disease. Baltimore: Williams and Wilkins 1999, 459�66.
2. Mock DM. Skin manifestations of biotin deficiency. Semin Dermatol 1991;10:296�302.
3. Said HM, Redha R, Nylander W. Biotin transport in the human intestine: inhibition by anticonvulsant drugs. Am J Clin Nutr 1989;49:127�31.
4. Zempleni J, Mock DM. Biotin biochemistry and human requirements. J Nutr Biochem 1999;10:128�38 [review].
5. Zempleni J, Mock DM. Marginal biotin deficiency is teratogenic. Proc Soc Exp Biol Med 2000;223:14�21 [review].
6. Zempleni J, Mock DM. Biotin biochemistry and human requirements. J Nutr Biochem 1999;10:128�38 [review].
7. Coggeshall JC, Heggers JP, Robson MC, Baker H. Biotin status and plasma glucose in diabetics. Ann NY Acad Sci 1985;447:389�93.
8. Koutsikos D, Agroyannis B, Tzanatos-Exarchou H. Biotin for diabetic peripheral neuropathy. Biomed Pharmacother 1990;44:511�4.
9. Hochman LG, Scher RK, Meyerson MS. Brittle nails: response to daily biotin supplementation. Cutis 1993;51:303�5.
10. Somer E. The Essential Guide to Vitamins and Minerals. New York: Harper 1995, 70�2.
11. Zempleni J, Mock DM. Biotin biochemistry and human requirements. J Nutr Biochem 1999;10:128�38 [review].