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Feeding dried purple laver (nori) to vitamin B12-deficient rats significantly improves vitamin B12 status

  • Shigeo Takenaka (a1), Sumi Sugiyama (a1), Shuhei Ebara (a2), Emi Miyamoto (a3), Katsuo Abe (a3), Yoshiyuki Tamura (a1), Fumio Watanabe (a3), Shingo Tsuyama (a4) and Yoshihisa Nakano (a2)...


To clarify the bioavailability of vitamin B12 in lyophylized purple laver (nori; Porphyra yezoensis), total vitamin B12 and vitamin B12 analogue contents in the laver were determined, and the effects of feeding the laver to vitamin B12-deficient rats were investigated. The amount of total vitamin B12 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 b12 compounds (cyano-, hydroxo-, sulfito-, adenosyl- and methylcobalamin), in which the vitamin b12 coezymes (adenosyl- and methylcobalamin) comprised about 60 % of the total vitamin b12. when 9-week-old vitamin b12-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 B12 deficiency) became undetectable and hepatic vitamin B12 (especially adenosylcobalamin) levels were significantly increased. These results indicate that vitamin B12 in dried purple laver is bioavailable to rats.


Corresponding author

*Corresponding author: Dr Shigeo Takenaka, present address Department of Veterinary Science, Osaka Prefecture University, Sakai, Osaka, 599-8531, Japan, fax + 81 722 54 9489, email


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Brass, EP & Stabler, SP (1988) Carnitine metabolism in the vitamin B-12-deficient rat. Biochemical Journal 255, 153159.
Dagnelie, PC, van Staveren, WA & van den Berg, H (1991) Vitamin B12 from algae appears not to be bioavailable. American Journal of Clinical Nutrition 53, 695697.
Fehling, C, Jagerstad, M & Aruidson, G (1978) Lipid metabolism in the vitamin-B12-deprived rat. Nutrition and Metabolism 22, 8289.
Frenkel, EP, Prough, R & Kitchens, RL (1980) Measurement of tissue vitamin B12 by radioisotopic competitive inhibition assay and a quantitation of tissue cobalamin fraction. Methods in Enzymology 67, 3140.
Herbert, V & Drivas, G (1982) Spirulina and vitamin B12. Journal of the American Medical Association 248, 30963097.
National Research Council (1985) Guide for the Care and Use of Laboratory Animals, Publication no. 85–23 (revised). Bethesda, MD: National Institutes of Health.
Rauma, AL, Törröen, R, Hänninen, O & Mykkänen, H (1995) Vitamin B12 status of long-term adherents of a strict uncooled vegan diet (‘living food diet’) is compromised. Journal of Nutrition 125, 25112515.
Resources Council, Science and Technology Agency (1984) Standard Tables of Food Composition in Japan 262267. Tokyo: Resources Council, Science and Technology Agency.
Resources Council, Science and Technology Agency (1995) Standard Tables of Food Composition in Japan–Vitamins K, B6 and B12 1656.Tokyo: Resources Council, Science and Technology Agency.
Schneider, Z (1987) The occurence and distribution of corrinoids Comprehensive B12 157223.[Schneider, ZStroinski, A, editors]. Berlin: Walter de Gruyer.
Toraya, T (1983) Assay methods for vitamin B12 I. Basic principles. Vitamins 57, 529538.
Toyoshima, S, Saido, H, Watanabe, F, Miyatake, K & Nakano, Y (1994) Assay for urinary methylmalonic acid by high-pressure liquid chromatography. Bioscience Biotechnology and Biochemistry 58, 18821883.
Van den Berg, H, Dagnelie, PC & van Staveren, WA (1988) Vitamin B12 and seaweed. Lancet i, 242243.
Watanabe, F, Katsura, H, Takenaka, S, Fujita, T, Abe, K, Tamura, Y, Nakatsuka, T & Nakano, Y (1999 a) Pseudovitamin B12 in the predominant cobamide of an algal health food. Spirulina tablets. Journal of Agricultural and Food Chemistry 47, 47364741.
Watanabe, F, Nakano, Y, Tachikake, N, Saido, H, Tamura, Y & Yamanaka, H (1991) Vitamin B12 deficiency increases the specific activity of rat liver NADH- and NADPH-linked aquacobalamin reductase isozymes involved in coenzyme synthesis. Journal of Nutrition 121, 19481954.
Watanabe, F, Nakano, Y, Tamura, Y & Yamanata, H (1991) Vitamin B12 metabolism in a photosynthesizing green alga, Chlamydomonas reinhardtii Biochimica et Biophysica Acta 1075, 3641.
Watanabe, F, Takenaka, S, Abe, K, Tamura, Y & Nakano, Y (1998) Comparison of a microbiological assay and a fully automated chemiluminescent system for the determination of vitamin B12 in food. Journal of Agricultural and Food Chemistry 46, 14331436.
Watanabe, F, Takenaka, S, Katsura, H, Zakir Hussan Masumder, SAM, Abe, K, Tamura, Y & Nakano, Y (1999 b) Dried green and purple lavers (Nori) contain substantial amounts of biologically active vitamin B12 but less of dietary iodine relative to other edible seaweeds. Journal of Agricultural and Food Chemistry 47, 23412343.
Weidemann, MJ, Hems, R, Williams, DL, Spray, GH & Krebs, HA (1970) Gluconeogenesis from propionate kidney and liver of the vitamin B12-deficient rat. Biochemical Journal 117, 177181.
Williams, DL & Spray, GH (1971) Metabolism effects of propionate in normal and vitamin B12-deficient rats. Biochemical Journal 124, 501507.
Yamada, S, Shibata, Y, Takayama, M, Narita, Y, Sugiwara, K & Fukuda, M (1997) Content and characteristics of vitamin B12 in some seaweeds. Journal of Nutritional Science and Vitaminology 42, 497505.
Yamada, K, Yamada, Y, Fukuda, M & Yamada, S (1999) Bioavailability of dried asakusanori (Porphyra tenera) as a source of cobalamin (vitamin B12). International Journal for Vitamin and Nutrition Research 69, 412418.
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British Journal of Nutrition
  • ISSN: 0007-1145
  • EISSN: 1475-2662
  • URL: /core/journals/british-journal-of-nutrition
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