Underestimated Danger: Cobalamin Deficiency in Type 2 Diabetes Mellitus

Abstract: 

Cobalamin is an essential biomolecule containing cobalt, entering the human body with food and by means of different transporters reaching the cells. There it binds to cellular receptors and activates certain biochemical reactions. It is essential mostly for the normal chemopoiesis and for the integrity of the nervous system. Some additional activities of cobalamin were established lately: some of them because of its direct effect and others due to other molecules in the body, that may increase or decrease, depending on the cobalamin levels in the circulation. A number of studies showed that due to different reasons a considerable part of elderly people over 60 have a cobalamin deficiency. This is true especially for the type 2 diabetic patients. Besides, metformin treatment may decrease the cobalamin levels in the body because of a decreased gastrointestinal absorption. Аccording to the last ADA and EASD international consensus metformin is a first choice drug for the treatment of Diabetes mellitus type 2 and it should be taken at all further steps of the treatment plan. This may precipitate or aggravate the cobalamin deficiency. On the other hand cobalamin deficiency may increase the risk of some diabetic complications and especially diabetic neuropathy. The mechanisms of direct or indirect action of cobalamin deficiency and their connection to diabetic complications are discussed. Recommendations for everyday practice are presented, since neither endocrinologists nor diabetic patients are properly informed about the consequences of cobalamin deficiency in type 2 diabetes mellitus; how to prevent it, how to overcome it and how to reduce additionally the risk of diabetic complications which may appear anyway even in patients with good glycemic control.