Vitamin B12 Status Among Patients With Type 2 Diabetes Mellitus

Background: Vitamin (vit.) B12 is a vital nutrient for ideal hemopoietic, neurocognitive, and cardiovascular integrity. The frequency of vit. B12 abnormalities in patients with type 2 diabetes mellitus (T2DM), especially with the chronic use of metformin, has been demonstrated and verified. In this study, the levels of vit. B12 and its metabolites in metformin-using T2DM participants were measured and compared to healthy participants to conclude any causal relationship. Methods: The study was conducted on selected T2DM patients who are using a high dose of metformin for the long term and compared to healthy volunteers regarding the following parameters: body mass index (BMI), waist circumference, complete blood cell (CBC), serum homocysteine, methylmalonic acid, transcobalamin, and holotranscobalamin. SPSS was used for data analysis, implementing the unpaired Student's t -test and the Chi-square test for significance. Results: Levels of holo-transcobalamin and homocysteine were insignificantly higher in T2DM patients. However, transcobalamin was insignificantly higher in the test group, while methylmalonic acid was surprisingly below the normal levels among both groups. No significant difference in BMI was reported between both groups, but T2DM patients had significantly higher waist circumferences compared to their healthy counterparts. Conclusions: The study showed high homocysteine levels in T2DM patients, consistent with the literature of similar studies of vit. B12 deficiency. However, it also showed unexplained reduced levels of methylmalonic acid and unexpectedly high levels of transcobalamin and homo-transcobalamin in the T2DM patients compared to the control group. These results indicate additional investigations are needed using a larger sample size of both groups to reach a meaningful conclusion.