title: Degradation of vitamin B12 in dietary supplements.
abstract: Beverages and solid dietary supplements rich in various added vitamins and minerals have recently become available. It seems reasonable to consider that the intake of these foods is convenient for easy ingestion of nutrients, but problems caused by blending different nutrients in high concentrations have arisen. We focused on vitamin B12 (B12) among vitamins and determined the B12 contents of beverages and solid dietary supplements purchased from a retail shop. The B12 contents of three of five beverages were less than stated on the labels. On the other hand, certain beverages unexpectedly contained much more B12 than stated on the labels. In these beverages the amount of B12 decreased rapidly with time, whereas B12 content was lower than stated on the label in only one of four solid dietary supplements. The content of B12 was affected by storage time, light exposure, temperature and vitamin C. From experimental analysis with a competitive binding assay method employing a ACS Chemiluminescent B12 kit, examining differential binding by intrinsic factors and spectral analysis of B12, it was determined that some of the B12 might have been converted into B12 analogues or small degradation products by multinutrient interaction during storage.
authors.affiliation: Department of Liberal Arts and Sciences, School of Health Sciences, Sapporo Medical University, Sapporo, Japan. oyama@sapmed.ac.jp
authors.forename: Keiko
authors.initials: K
authors.lastname: Yamada
authors.forename: Michiko
authors.initials: M
authors.lastname: Shimodaira
authors.forename: Seiko
authors.initials: S
authors.lastname: Chida
authors.forename: Noriko
authors.initials: N
authors.lastname: Yamada
authors.forename: Norio
authors.initials: N
authors.lastname: Matsushima
authors.forename: Morimichi
authors.initials: M
authors.lastname: Fukuda
authors.forename: Shoji
authors.initials: S
authors.lastname: Yamada