Web Release Date: May 11,
Dried Green and Purple Lavers (Nori) Contain Substantial Amounts of Biologically Active Vitamin B12 but Less of Dietary Iodine Relative to Other Edible Seaweeds
and
Department of Health Science, Kochi Women's University, Kochi 780-8515, Japan, Laboratory of Nutrition and Food Science, Hagoromo-gakuen College, Sakai 592-8344, Japan, and Department of Applied Biological Chemistry, Osaka Prefecture University, Sakai 599-8531, Japan
Received for review September 29, 1998. Revised manuscript received March 5, 1999. Accepted March 23, 1999. This study was supported in part by a research fund (Gakucho-tokubettuwaku-josheikin) of Kochi Women's University.
Abstract:
Vitamin B12 concentrations of dried green (Enteromorpha sp.) and purple (Porphyra sp.) lavers (nori)
were determined by both Lactobacillus leichmannii ATCC 7830 microbiological and intrinsic factor
chemiluminescence methods. The values determined by using the microbiological method (63.58 ±
2.90 and 32.26 ± 1.61 
g/100 g of dry weight) were identical to those found by using the
chemiluminescence method (69.20 ± 2.21 and 25.07 ± 0.54 g/100 g of dry weight) in both dried
green and purple lavers, respectively. A silica gel 60 thin-layer chromatography of both laver extracts
shows that non-coenzyme forms (hydroxo and cyano forms) of vitamin B12 predominate in both dried
lavers. The dried lavers contained lesser amounts of dietary iodine (~4-6 mg/100 g of dry weight)
relative to other seaweeds, suggesting that excessive intake of the dried lavers is unlikely to result
in harmful intake of dietary iodine. These results indicate that the dried lavers (nori) are the most
excellent source of vitamin B12 among edible seaweeds, especially for strict vegetarians.
Keywords: Vitamin B12; dried edible seaweeds, green and purple lavers; nori; intrinsic factor; Lactobacillus leichmannii; dietary iodine; vegetarians
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