Are you getting enough of this vitamin? If you're a vegetarian or over age 60, you need to be concerned about getting enough vitamin B12.
D000367:Age Factors; D014676:Diet, Vegetarian; D006801:Humans; D008875:Middle Aged; D014805:Vitamin B 12 / Q000008:administration & dosage* / Q000378:metabolism; D014806:Vitamin B 12 Deficiency / Q000209:etiology*
D014805:Vitamin B 12