The association of vitamin B12 deficiency and metformin

Metformin is the most widely used oral antidiabetic agent for the treatment of type 2 diabetes (T2D) and the association of the use of this drug with vitamin B12 deficiency has been described. A review of studies was carried out to find out the evidence of this association and the recommendations for its detection, prevention and treatment. The reported prevalence of vitamin B12 deficiency in patients treated with metformin ranged from 5.8% to 52% in the different series. Older patients, those who received metformin at high doses and for a longer time, and those who do not consume food of animal origin, are those who are at greater risk of suffering from this deficit.