Prevalence of vitamin B12 deficient Korean centenarians on the traditional semi-vegetarian was not higher compared with those from Western nations with animal-oriented foods. Screening of vitamin B12 contents has revealed that some traditional soybean-fermented foods, such as Doenjang and Chunggukjang, also Gochujang, Ganjang (soy sauce), cabbage Kimchi, and seaweeds (laver , sea lettuce, sea tangle, sea mustard ) contain considerable amounts of vitamin B12. Soybeans (steamed) and tofu do not contain B12.
Laver, dried, seasoned & toasted - 55 -71 mcg in 100 g dry weight
Sea lettuce, raw - 85 mcg in 100 g dry weight
Recommended Dietary Allowance (RDA) - the average daily dietary nutrient intake level sufficient to meet the nutrient requirement of nearly all - ~97% - healthy individuals in a particular life stage and gender group.
The process for setting the RDA depends on being able to set an Estimated Average Requirement (EAR). If an EAR cannot be set, no RDA will be set. The EAR is the daily intake value of a nutrient that is estimated to meet the nutrient requirement of half the healthy individuals in a life stage and gender group.
The RDA is set at the EAR plus twice the standard deviation (SD) if known (RDA = EAR + 2 SD). If data about variability in requirements are insufficient to calculate a standard deviation, a coefficient of variation for the EAR of 10% is ordinarily assumed (RDA = 1.2 x EAR).
The RDA for a nutrient is a value to be used as a goal for dietary intake by healthy individuals. The RDA is not intended to be used to assess the diets of either individuals or groups or to plan diets for groups.