is vitamin b12 deficiency common
Vitamin B 12 (cobalamin) deficiency is a common cause of macrocytic anemia and has been implicated in a spectrum of neuropsychiatric disorders.The role of B 12 deficiency in hyperhomocysteinemia and the promotion of atherosclerosis is only now being explored.itamin B 12 deficiency, therefore, can lead to increased levels of serum methylmalonic acid. In the second reaction, homocysteine is converted to methionine by using vitamin B 12 and folic acid as cofactors. In this reaction, a deficiency of vitamin B 12 or folic acid may lead to increased homocysteine levels.