Low serum Vitamin B12 levels may be associated with many medical
conditions related to an inadequate vitamin B12 intake or
reduced gastric secretion of intrinsic factor, which inhibits
absorption. As a dietitian in the clinic, I typically ask my
patients about their overall dietary patterns to see what
sources of Vitamin B12 they may be lacking and we then work
towards adding some of these foods and/or supplementing with a
Vitamin B-12 supplement. According to the 2005-2006 National
Health and Nutrition Education Survey (NHANES), the average
vitamin B12 intake from food for adults 20 and over was 5.64
mcg.Vitamin B12 is found only in foods of animal origin or in
fermented foods where bacteria produce the vitamin. Organ meats
are the best sources of vitamin B12 (liver, kidney, heart, and
pancreas), followed by clams, oysters, extra-lean beef, seafood,
eggs, milk and yogurt, chicken, cheese, and miso (a fermented
soybean product). For people who lack intrinsic factor, it has
been found that a 1,000 mcg daily or