Characterization of vitamin B 12 compounds from marine foods

Vitamin B12 is synthesized by only certain bacteria and archaea but not by animals or plants. In marine environments, bacterial vitamin B12 is transferred and concentrated into fish and shellfish bodies by plankton in the marine food chain. Moreover, marine macrophytic red algae, Porphyra spp. specifically contain substantial amounts of vitamin B12, due to microbial interaction. Although some meats or viscera of edible fish and shellfish are excellent sources of biologically active vitamin B12, an inactive corrinoid, pseudovitamin B12, was found in some edible shellfish using liquid chromatography/electrospray ionization–tandem mass spectrometry. To prevent elderly people from developing vitamin B12 deficiency due to food protein-bound vitamin B12 malabsorption, we present a survey of marine foods containing free vitamin B12. The results of our study suggest that bonito and clam extracts (or soup stocks), which contain considerable amounts of free vitamin B12 are useful not only as seasonings and flavorings but also as excellent sources of free vitamin B12.