The effects of vitamin B12: 1, can prevent and alleviate the occurrence of anemia, especially megaloblastic anemia patients appropriate consumption of vitamin B12, have a good preventive and alleviating effect. 2, can reduce the incidence of cardiovascular disease, because for cardiovascular disease hyperhomocysteinemia is a risk factor, and vitamin B12 is involved in the metabolism of methionine, homocysteine, for the reduction of homocysteine level has an important regulatory role. Vitamin B12 is involved in the metabolism of methionine and homocysteine and has an important regulatory role in lowering homocysteine levels, so it has a good effect in preventing cardiovascular and cerebrovascular diseases. 3, it can protect the function of the nervous system, so it has a good preventive and therapeutic effect on patients with abnormal mood, dull expression and slow reaction.