(NaturalNews) Nori, also known as purple laver or Porphyra yezoensis, may be the most popular seaweed in the United States. Nori is the seaweed most widely used as a wrap for sushi. It is usually sold in large, thin, dried sheets. Traditional Asian cultures have known for centuries of the extremely high mineral content - especially iodine -in all seaweeds. Iodine is essential for proper thyroid function.
Nori has more protein per weight than either sunflower seeds or wheat germ. Just 100 grams, or roughly one cup of nori contains 41.4 grams of protein. In addition, the seaweed is rich in vitamins A, C and B-12. The high vitamin B-12 content in nori makes this sea vegetable a favorite among vegetarians.
A lower iodine content compared to other seaweeds makes nori safe for long-term use
In 1999, the Journal of Agricultural and Food Chemistry published a clinical study to determine the amount of bio-available vitamin B-12 in dried nori. While the scientists measured sizable amounts of vitamin B-12, they also noted that nori contains less iodine than other forms of sea vegetables, such as kelp. The scientists remarked that even an excessive intake of nori would not create an overdose of iodine. This makes nori an excellent candidate for long-term consumption of plant-based iodine. They also believed that nori was the best source of vitamin B-12 among seaweeds for vegans.
Does it matter whether nori is raw or dried?
The International Journal for Vitamin and Nutrition Research confirmed in another 1999 clinical study that nori is an excellent source of natural B-12. However, the study went on to remark that dried nori actually had a negative effect on vegetarian children. The researchers were curious to see why dried and raw nori had such different results. They discovered that when nori was dried, the chemical composition changed from genuine B-12 to a harmful analogue -- something similar to B-12 that actually caused the B-12 levels in children to drop. Vegan parents may want to exercise caution and find a different source of Vitamin B-12 for their children.
After the 1999 study was published, a team of scientists from the Laboratory of Nutrition and Food Science at Hagoromo-gakuen College in Japan decided to confirm the findings concerning dried nori and B-12 loss. Vitamin B-12 deficient rats were fed dried nori which contained five different forms of vitamin B-12. Interestingly, when these rats were measured for vitamin B-12 deficiency in their urine, there was none at all. In addition, the amount of vitamin B-12 in the rat's bloodstream significantly increased. The researchers concluded that the vitamin B-12 contained in dried nori is definitely bio-available to rats.
Sources for this article include:
Pubmed.gov, "Bio-availability of dried asakusanori (porphyra tenera) as a source of Cobalamin (Vitamin B-12). K. Yamada, et al. International Journal of Vitamin and Nutrition Research, November 1999; 69(6): 412-8. http://www.ncbi.nlm.nih.gov/pubmed/10642899
Pubmed.gov, "Feeding dried purple laver (nori) to vitamin B 12-deficient rats significantly improves vitamin B 12 status." S. Takenaka, et al. British Journal of Nutrition, June 2001; 85(6): 699-703. http://www.ncbi.nlm.nih.gov/pubmed/11430774
Pubmed.gov, "Dried green and purple lavers (Nori) contain substantial amounts of biologically active vitamin B(12) but less of dietary iodine relative to other edible seaweeds." F. Watanabe, et al. Journal of Agricultural and Food Chemistry June 1999; 47(6): 2341-3. http://www.ncbi.nlm.nih.gov/pubmed/10794633