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Feeding dried purple laver (nori) to vitamin B 12 -deficient rats significantly improves vitamin B 12 status

2001; Cambridge University Press; Volume: 85; Issue: 6 Linguagem: Inglês

10.1079/bjn2001352

1475-2662

Shigeo Takenaka, Sumi Sugiyama, Shuhei Ebara, Emi Miyamoto, Katsuo Abe, Yoshiyuki Tamura, Fumio Watanabe, Shingo Tsuyama, Yoshihisa Nakano,

Porphyrin Metabolism and Disorders

To clarify the bioavailability of vitamin B 12 in lyophylized purple laver (nori; Porphyra yezoensis ), total vitamin B 12 and vitamin B 12 analogue contents in the laver were determined, and the effects of feeding the laver to vitamin B 12 -deficient rats were investigated. The amount of total vitamin B 12 in the dried purple laver was estimated to be 54.5 and 58.6 (SE 5.3 and 7.5 respectively) ΜG/100 g dry weight by lactobacillus bioassay and chemiluminescent assay with hog intrinsic factor respectively. the purple laver contained five types of biologically active vitamin b 12 compounds (cyano-, hydroxo-, sulfito-, adenosyl- and methylcobalamin), in which the vitamin b 12 coezymes (adenosyl- and methylcobalamin) comprised about 60 % of the total vitamin b 12 . when 9-week-old vitamin b 12 -deficient rats, which excreted substantial amounts of methylmalonic acid (71.7(se 20.2) μmol/d) in urine, were fed the diet supplemented with dried purple laver (10 μg/kg diet) for 20 d, urinary methylmalonic acid excretion (as an index of vitamin B 12 deficiency) became undetectable and hepatic vitamin B 12 (especially adenosylcobalamin) levels were significantly increased. These results indicate that vitamin B 12 in dried purple laver is bioavailable to rats.