Vitamin B12 level Drops Progressively as Diabetics Take Metformin

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This study is uncomforting. We all agree that the true reason for treating diabetes is to reduce or eliminate its complications. And here, evidence shows that the treatment we give to reduce these complications can actually cause them!

In this study 19% of 196 diabetics on Metformin 850mg TID had a progressive drop in their vitamin B12 levels. This study also assessed folic acid levels. With folic acid there was a non-significant trend for lower levels.

Long term treatment with metformin in patients with type 2 diabetes and risk of vitamin B-12 deficiency: randomised placebo controlled trial -- de Jager et al. 340: c2181 -- BMJ