Determination of Vitamin B12 and Folate Compounds in Commercially Available Edible Seaweed Products.

Background: Information on the contents of both vitamin B12 and folate in edible seaweeds is limited, of which deficiencies disrupt methionine biosynthesis to accumulate homocysteine as a risk factor of cardiovascular diseases.

Methods: Both vitamins were determined in commercially available edible seaweed products using high-performance liquid chromatography.

Results: Dried purple laver (Neopyropia yezoensis) products contain higher levels of vitamin B12 (approximately 30-60 μg/100 g dry weight) and folate compounds (approximately 880-1300 μg/100 g dry weight) than other seaweed products, such as kombu (Saccharina japonica), hijiki (Sargassum fusiformis), and wakame (Undaria pinnatifida). 5-methyltetrahydrofolate was the major folate compound in purple laver products. 5-formyltetrahydrofolate was found at a moderate level, whereas tetrahydrofolate, 5,10-metenyltetrahydrofolate, 10-formyltetrahydrofolate, and folic acid were found to be minor folate compounds.

Conclusions: These findings suggest that dried purple laver (nori) products are suitable sources of vitamin B12 and folate compounds for humans, especially vegetarians.