title: Biotin analysis of commercial vitamin and other nutritional supplements.
abstract: Because previous observations suggest that biotin may be present in vitamin preparations not labeled as containing biotin, we determined the biotin content of several over-the-counter vitamin and nutritional supplements said to contain biotin (group 1) and several in which biotin content was not specified (group 2). Biotin concentration was measured using the 125I-avidin assay which detects total avidin-binding substances. Water extracts were assayed for free biotin and acid hydrolysates were assayed for total biotin. The results of the 125I-avidin assay agreed with the stated biotin content for most vitamin and nutritional supplements in group 1. Biotin was the only avidin-binding substance in the preparations from group 1, based on reversed-phase chromatography. However, some vitamin and nutritional supplements in group 2 contained nutritionally significant amounts of biotin, particularly if the supplement contained liver or yeast extract. Total biotin was significantly higher than free biotin in one supplement; the difference was attributable to release of biotin rather than a biotin analog. We conclude that biotin may be present in some vitamin and nutritional supplements not labeled as containing biotin; biotin intake might be under-estimated if the subject is receiving a nutritional supplement containing extracts of liver or yeast.
authors.affiliation: Department of Pediatrics, College of Medicine, University of Iowa, IA 52242.
authors.forename: N
authors.initials: N
authors.lastname: Tolaymat
authors.forename: D M
authors.initials: DM
authors.lastname: Mock
mesh_terms: D000143:Acids; D001710:Biotin / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D004348:Drug Labeling; D005515:Food Labeling; D005527:Food, Fortified / Q000032:analysis*; D005525:Food-Processing Industry; D006801:Humans; D006868:Hydrolysis; D008110:Liver Extracts / Q000032:analysis; D009751:Nutritional Requirements; D014815:Vitamins / Q000032:analysis*; D015003:Yeasts / Q000032:analysis
chemical_list: D000143:Acids; D008110:Liver Extracts; D014815:Vitamins; D001710:Biotin