Vitamin B12 and Disease
Vitamin B12 and the associated amino acids methionine and cysteine are essential to avoid specific symptoms of anemia and the deleterious effects of inflammation. Vitamin B12, cobalamin, cannot be made by the human body and requires a protein secreted by stomach cells, intrinsic protein, for uptake from the diet or from gut bacteria. In the absence of dietary B12, individuals can develop pernicious anemia. Since vitamin B12 is used by enzymes involved in nucleic acid synthesis, the rapidly dividing cell of the blood show the first symptoms. Another feature of pernicious anemia is the production of autoimmune antibodies against gastric intrinsic protein. This means that even if the diet is supplemented with vitamin B12, the anemic patient would show no improvement. Historically, the cure was beef liver juice containing B12 already bound to intrinsic factor. I enjoyed learning about the autoimmune aspect of pernicious anemia, because when I examined the sequence of the human i...