Metformin Hikes B12 Deficiency in Type 2 Diabetes

HealthDay News— The use of metformin therapy in adults with type 2 diabetes is linked to a biochemical B12 deficiency greater than that found in other adults with type 2 diabetes and adults without diabetes, and current over-the-counter supplements are not sufficient to correct the deficiency in either of these type 2 diabetes groups, according to research published online Dec. 16 in Diabetes Care.

Lael Reinstatler, MPH, of the Rollins School of Public Health at Emory University in Atlanta, and colleagues analyzed data from the National Health and Nutrition Examination Survey to determine the prevalence of biochemical B12 deficiency in adults aged 50 years and older with type 2 diabetes taking metformin, compared with those not taking metformin and those without diabetes. They also sought to determine whether this relationship could be modified by vitamin B12 supplementation.

The researchers found biochemical B12 deficiency present in 5.8% of 575 adults aged 50 and older with type 2 diabetes who used metformin, compared to 2.4% of 1,046 adults not using the therapy. The deficiency was also found in 3.3% of 6,867 adults without diabetes. Taking supplements containing vitamin B12 was not associated with reducing biochemical deficiencies among the study group with diabetes. However, for those without diabetes, consumption of any vitamin supplements containing B12 resulted in reducing deficiencies by two-thirds.

“Our results have public health and clinical implications by suggesting that neither 2.4µg, the current Institute of Medicine recommendation for daily B12 intake, nor 6µg, the amount found in most multivitamins, is sufficient for those with type 2 diabetes taking metformin,” the authors write.

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