Discovery of Novel Sources of Vitamin B12 in Traditional Korean Foods from Nutritional Surveys of Centenarians PMID: 21436999
Human longevity can be explained by a variety of factors, among them, nutritional factor would play an important role. In our study of Korean centenarians for their longevity, the apparent nutritional imbalance in the traditional semi-vegetarian diet raised a special attention, especially on vitamin B12 status, supplied by animal foods. Interestingly, we found that the prevalence of vitamin B12 deficient Korean centenarians was not higher compared with those from Western nations with animal-oriented traditional foods. We assumed that there might be some unveiled sources for vitamin B12 in the Korean traditional foods. Screening of vitamin B12 contents has revealed that some traditional soybean-fermented foods, such as Doenjang and Chunggukjang, and seaweeds contain considerable amounts of vitamin B12. Taken together, it can be summarized that the traditional foods, especially of fermentation, might be evaluated for compensation of the nutritional imbalance in the vegetable-oriented dietary pattern by supplying vitamin B12, resulting in maintenance of health status.It was interesting that vitamin B12 was not detected in steamed-soybeans and tofu; however, it was detected in fermented-soybean products. Moreover, traditional home-made soybean-fermented foods such as Doenjang, Chungkookjang, and Gochujang were found to contain higher vitamin B12 than commercial factory-made products. Traditional home-made Doenjang is a “slow food” taking at least 10 months for preparation and fermented by multiple microorganisms found in nature. However, the commercial product made in the factory takes only 3-4 months and is fermented by inoculated microorganisms under strict conditions. Due to the needs of space, time, and labor and the smell during the preparations and storage of Doenjang, the commercial Doenjang is increasingly popular, particularly to the younger generations living in urban areas. However, most Korean people living in rural areas still make it by themselves at home and consume it all year round. We observed that all the Korean centenarian subjects who participated in our studies were consuming the traditional home-made fermented foods.
Table 5: Vitamin B12 content in Korean fermented foods and some popular foods.
Doenjang (bean paste):
This seems to be about the same study:
Vitamin B12 Contents in Some Korean Fermented Foods and Edible Seaweeds.
Kwak CS, Hwang JY, Watanabe F, Park SC.
Institute on Aging,1) Seoul National University, Seoul 110-810, Korea. kwakcs@snu.ac.kr
Department of Agriculture,2) Biological and Environmental Sciences, Tottori University, Tottori 680-8550, Japan.
The Aging and Apoptosis Research Center,3) Seoul National University, Seoul 110-510, Korea.
Abstract
There is a limitation to estimate vitamin B12 intake due to lack of data on vitamin B12 content in many Korean foods. In this study, vitamin B12 content was determined in some soybean or vegetable-fermented foods, edible seaweeds and other frequently consumed foods in Korea by microbioassay using Lactobacillus delbruecki ATCC 7830. The traditional type of Doenjang and Chungkookjang contained 1.85 microgram/100 g and 0.69 microgram/100 g of vitamin B12, respectively, while the factory-type of Doenjang and Chungkookjang contained 0.04-0.86 microgram/100 g and 0.06-0.15 microgram/100 g. Vitamin B12 was not detected in steamed soybeans and Tofu which is a not-fermented soybean product, indicating that vitamin B12 in Doenjang and Chungkookjang might be produced during the fermentation process. The Korean-style soy sauce contained 0.04 microgram vitamin B12/100 mL, but vitamin B12 was not detected in Japanese-style soy sauce and white miso. Commercial Kimchi, a representative Korean vegetable- fermented food, made of Korean cabbage, Yeolmu, or Mustard leaves contained 0.013-0.03 microgram vitamin B12/100 g, while Kimchi without red pepper and fermented fish sauce (White Kimchi) did not. Vitamin B12 content was very high in some edible seaweeds such as laver (66.76 microgram/ 100 g dry weight) and sea lettuce (84.74 microgram/100 g dry weight), and it was 17.12 microgram/100 g of dried small anchovy, 1.07 microgram/100 g of whole egg, and 0.02 microgram/100 g of coffee mix. From these results, it is assumed that Koreans take substantial amount of vitamin B12 from plant-origin foods. And, with these data, we will be able to calculate dietary vitamin B12 content more correctly than before. In conclusion, soybean-fermented foods, Kimchi, laver and sea lettuce are recommendable as good sources of vitamin B12 for vegetarians or Korean elderly on grain and vegetable based diet.
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