The existence of vitamin B12, often designated the antipernicious anemia or animal protein factor, as another member of the expanding family of vitamins is well established. As implied from its nomenclature, it belongs to the water soluble B-vitamins, but unlike most other vitamins in this group its chemical structure is unknown. Its nutritional importance to man, his monogastric farm animals and his poultry is recognized. For the present, at least, the supply consists primarily of concentrates. It is not to be inferred that crystalline B12 is unavailable. On the contrary, however, the supply is very limited and unitages of activity comparable to those in concentrates are much more costly. Consequently, the supply of crystalline material is limited largely to the pharmaceutical trade whereas the livestock and poultry industries rely principally upon concentrates.
Proceedings of the Iowa Academy of Science
©1951 Iowa Academy of Science, Inc.
Cheng, Edmund Wei-Kuang and Thomas, Byron H.
"Vitamin B12 Content of Kidneys as Determined by Different Bioassay Procedures,"
Proceedings of the Iowa Academy of Science, 58(1), 265-274.
Available at: https://scholarworks.uni.edu/pias/vol58/iss1/30