Adult-onset diabetes, or type 2 diabetes mellitus (T2DM), is an important and growing chronic public health issue in communities here in the United States (US) and across the globe. Type 2 diabetes is a chronic condition that affects the patient’s ability to absorb the sugar from their blood into the cells of their body and often results in high blood sugar and a wide variety of associated symptoms. A drug called metformin, taken orally, is often one of the first medication-based approaches that a doctor uses to treat patients who are diagnosed with type 2 diabetes. Metformin works by reducing and inhibiting a process called gluconeogenesis, which produces glucose, and, therefore, acts as a blood sugar-lowering agent. However, among several side effects of taking metformin is an increased risk for a vitamin B12 deficiency. Vitamin B12 plays a crucial role in the body; it is involved in many vital functions, such as red blood cell production, DNA production, and repairing damaged cells and tissues.
A patient with T2DM checks their blood sugar levels.
Image Source: Andriy Onufriyenko
A study done in the Irish population of patients with T2DM set out to find out if taking metformin causes vitamin B12 deficiency in diabetes patients. The researchers based their findings on data they collected from patient health records at Beaumont Hospital in Dublin, Ireland. The patients they included in the cross-sectional study were not taking any vitamin B12 supplements and had all been prescribed metformin for at least a year and a half. This study included 216 patients with T2DM taking metformin and a control group of 70 patients also with T2DM who were not taking metformin. The researchers ensured the groups had similar demographic factors and metabolic values.
The study found that vitamin B12 levels had an inverse relationship with metformin use; a longer duration of taking metformin was associated with a greater magnitude of vitamin B12 deficiency. Vitamin B12 deficiency was higher in the group of patients taking metformin than not taking it, to a statistically significant degree. Vitamin B12 deficiency can also lead to harmful effects in the body, including anemia,(low red blood cell count), or peripheral neuropathy , (pain from nerve damage in the limbs).
Though this study was done in the Irish population, and it is possible that the results may differ, if a population of American patients repeats this study, many of the underlying factors that are causing the increasing prevalence of T2DM in the community are translatable to the American population, like obesity and a sedentary lifestyle.
These findings are clinically relevant, because they can prompt physicians to ensure that vitamin B12 levels, specifically in diabetes patients, are a prominent factor when examining and monitoring the overall health of T2DM patients taking metformin. Patients who are on metformin therapy for T2DM are monitored for side effects and associated symptoms at least every year, and these findings indicate that vitamin B12 should always be an important metric in this check-up.
Featured Image: barmaleeva
