The need for vitamin B12 and folic acid inthe formation of red blood cells is related primarily of their effects on:
Within 6-9 hours of treatment with vitamin B12 formation of nuclear DNA component promotes normoblastic reaction of the bone marrow. Folic acid also promotes the formation of nucleic acids.
Synthesis and release of erythropoietin from the kidney
Absorption of iron from the gut
DNA synthesis in bone marrow
Hemoglobin formation in the red blood cell