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 B(12) 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 microg/day, and 52.7% of subjects consumed under estimated average requirement, 2.0 microg/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 microg/day) than those with normal serum vitamin B(12) (3.47 microg/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.