Patients Using Metformin at Risk for B12 Deficiency

Patients Using Metformin at Risk for B12 Deficiency: Patients treated over long periods with metformin, are at risk of developing vitamin B12 deficiency which is also likely to get worse over time, according to a study. The findings suggest that regular checking of vitamin B-12 levels during long-term metformin treatment should be “strongly considered” to try to prevent deficiency and its effects. Vitamin B12 is essential to maintain healthy nerve cells and red blood cells. It is found in meat, dairy products, eggs, fish, shellfish and fortified breakfast cereals, and it also can be taken as a supplement. Symptoms of B12 deficiency include fatigue, mental changes, anemia and nerve damage known as neuropathy. All these symptoms can easily be misdiagnosed as being due to diabetes and its complications, or to ageing, but checking B12 levels could help doctors to assess the real cause and treat it if it was found to be B12 deficiency. They found that people who had taken the metformin had a 19% reduction in their vitamin B12 levels compared with people who had taken a placebo, who had almost no B12 change. The reduced levels of vitamin B12 in the metformin group also persisted and became more apparent over time. BMJ, Oct 2010