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Titre du document / Document title

Bioavailability of dried asakusanori (Porphyra tenera) as a source of cobalamin (vitamin B12)

Auteur(s) / Author(s)

YAMADA K. (1) ; YAMADA Y. (2) ; FUKUDA M. (3) ; YAMADA S. (2) ;

Affiliation(s) du ou des auteurs / Author(s) Affiliation(s)

(1) Department of Liberal Arts and Sciences, School of Health Sciences, Sapporo Medical University, South-1 and West-17, Sapporo 060-8556, JAPON
(2) Department of Home Economics, Faculty of Education, Hokkaido University of Education, Ainosato, Sapporo 002-8075, JAPON
(3) Department of Laboratory Diagnostic Ultrasound and Medical Electronics, School of Medicine, Sapporo Medical University, Sapporo 060-8556, JAPON

Résumé / Abstract

We have already reported that raw nori (Porphyra tenera) contains cobalamin (Cbl) but not Cbl analogues (J. Nutr. Sci. Vitaminol., 42,497, 1996). It seems, therefore, that it is an excellent natural vegetable source of Cbl. On the other hand, it has been reported that the Cbl nutritional status of vegetarian children deteriorated as estimated by the hematological index, mean corpuscular volume (MCV), after they had dried nori as a source of Cbl. Such a discrepancy between raw and dried nori as a source of Cbl led us to investigate whether Cbl in dried nori had different properties from that in raw nori. We found that contents of Cbl homologues determined by a bioassay method in both raw and dried nori were similar. The urinary methylmalonic acid excretion increased when human female volunteers were given 40 g of dried nori daily during the test period. On the other hand, the urinary methylmalonic acid excretion did not change when volunteers were daily given 320 g of raw nori, which was equivalent to 40 g of the dried one on the basis of dehydrated weight, during the test period. By paper chromatography, 65% of the Cbl homologues were found to be comprised of Cbl analogues in dried nori, while 73% of the Cbl homologues in the raw nori were genuine Cbl. These results were confirmed by the finding that the bioassay method gave higher values for Cbl homologues than those obtained by a competitive binding assay method using an intrinsic factor as a Cbl-binding protein. Our present data demonstrated that Cbl in raw nori can be changed into harmful Cbl analogues by the drying process.

Revue / Journal Title

International journal for vitamin and nutrition research    ISSN  0300-9831   CODEN IJVNAP 

Source / Source

1999, vol. 69, no6, pp. 412-418 (26 ref.)

Langue / Language

Anglais

Editeur / Publisher

Huber, Bern, SUISSE  (1971) (Revue)

Mots-clés anglais / English Keywords

Dehydrated product

;

Edible alga

;

Supplemented diet

;

Bioavailability

;

Cyanocobalamin

;

Human

;

Plant origin

;

Feeding

;

B-Vitamins

;

Rhodophyta

;

Algae

;

Thallophyta

;

Mots-clés français / French Keywords

Produit déshydraté

;

Algue comestible

;

Régime alimentaire enrichi

;

Biodisponibilité

;

Cyanocobalamine

;

Homme

;

Porphyra tenera

;

Origine végétale

;

Alimentation

;

Vitamine B

;

Rhodophyta

;

Algae

;

Thallophyta

;

Mots-clés espagnols / Spanish Keywords

Producto deshidratado

;

Alga comestible

;

Régimen alimenticio enriquecido

;

Biodisponibilidad

;

Cianocobalamina

;

Hombre

;

Origen vegetal

;

Alimentación

;

Vitamina B

;

Rhodophyta

;

Algae

;

Thallophyta

;

Localisation / Location

INIST-CNRS, Cote INIST : 844, 35400008088834.0060

Nº notice refdoc (ud4) : 1239608



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