Dietary source of vitamin B12 intake and vitamin B12 status in female elderly Koreans aged 85 and older living in rural area

Recently, we found and analyzed vitamin B-12 in some Korean traditional plant foods which had not reported, yet. This study was to investigate vitamin B-12 intake and its dietary sources and the vitamin B-12 status in the very old elderly Koreans. We measured serum vitamin B-12 level and estimated the amounts of vitamin B12 intake from different dietary sources in female elderly Koreans aged 85 and over who had consumed a relatively low animal traditional diet for the whole life. The average age of the subjects (n = 127) was 98.0 years (85-108 years). The assessment on energy and nutrient intake involved a one-day 24-hour recall, and serum vitamin B-12 concentration was measured by radioimmunoassay. Overall diet pattern was not different between the 85-99 yr-old group and centenarians, except centenarians were taking more dairy product. The average ratio of plant food to animal food consumption was 87.5:12.5 in weight. The average vitamin B-12 intake of our subjects was 3.2 mu g/day, and 52.7% of subjects consumed under estimated average requirement, 2.0 mu g/day. On dietary source, 67.3% of dietary vitamin B-12 was from meat, eggs and fishes and 30.6% was from plant foods, such as soybean-fermented foods, seaweeds, and kimchi. The average serum vitamin B-12 concentration was 450.5 pg/mL, and low serum vitamin B-12 (<200 pg/mL) was found in 9.6% of subjects. Dietary vitamin B-12 intake was significantly lower in subjects with low serum vitamin B-12 (0.79 mu g/day) than those with normal serum vitamin B-12 (3.47 mu g/day). There were no significant difference in vitamin B-12 intake and its dietary sources and serum vitamin B-12 level between the 85-99 yr- old group and centenarians. In conclusion, several plant-origin foods including seaweed, soybean-fermented foods, and kimchi, may contribute significantly to good vitamin B-12 status in very old elderly Koreans.