Andrès and colleagues remind us that food cobalamin malabsorption can be a problem that is distinct from pernicious anemia, and they provide interesting observations on its relative frequency but fail to convince us that there is practical value in performing Schilling tests or checking auto-antibody levels in typical patients with B12 deficiency.
There is little reason to treat food cobalamin malabsorption differently than pernicious anemia. Food cobalamin malabsorption may sometimes respond poorly to oral cyanocobalamin (vitamin B12) treatment.1 On the other hand, nonparenteral forms of vitamin B12 (oral, sublingual, or intranasal) can often successfully treat both forms of vitamin B12 malabsorption.2- 4 Andrès et al laud the Schilling test for its ability to distinguish food cobalamin malabsorption from pernicious anemia, but I judge that the inability of the Schilling test to detect vitamin B12 malabsorption from food is a serious limitation that decreases its clinical relevance.
Rice L. Food Cobalamin Malabsorption: A Usual Cause of Vitamin B12 Deficiency—Reply. Arch Intern Med. 2000;160(13):2061-2067. doi: