This is because both are necessary for DNA synthesis and healthy red blood cells.
Explanation:
Vitamin B12 provides structural stability to some chromosome regions as centromere and telomeric DNA.
Vitamin B12 helps in methylation of DNA as a coenzyme since it is a methyl group donor.
Not having vitamin B12 in diet leads to lowering and obstruction in DNA synthesis leading to damage to DNA.
The deficiency of vitamin B12 causes apoptosis of erythroblast cells. If no vitamin B12 is there the red blood cells undergo abnormal divisions and are so large in size that they do not leave the bone marrow causing the deficiency of hemoglobin this condition is called as megabloblastic anaemia.
