title: Adverse effect of metformin therapy on serum vitamin B12 and folate: short-term treatment causes disadvantages?
abstract: Diabetes is a global public health challenge that imposes heavy burdens on communities and individuals. Metformin, the first-line medication for diabetes, has the superiority of reducing risk of macrovascular diseases, all-cause mortality and even possibly cancers. Recent observational studies, however, have demonstrated that long-term metformin therapy increases the probability of vitamin B12 and folate deficiency, and might contribute to the progression of diabetic peripheral neuropathy. Despite metformin is widely used and extensively studied, randomized controlled trials performed to explore the effects of metformin on vitamin B12 and folate are limited. Besides, whether short-term treatment causes vitamin deficiency is a pending issue. We postulate that even a few-month treatment with metformin results in the decrease of vitamin B12 and folate. However, supplementation of vitamin B12 rather than the combination of vitamin B12 and folate might be profitable based on the mechanism of metformin on vitamins in patients with type 2 diabetes. This viewpoint differs from those of majority that a combined supplementation of vitamin B12 and folate is inclined to be advised.
authors.affiliation: Department of Endocrinology, The First Affiliated Hospital of Sun Yat-sen University, 58th of Zhongshan Er Road, Guangzhou 510080, China.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Xu
authors.forename: Zhimin
authors.initials: Z
authors.lastname: Huang
authors.forename: Xiaoying
authors.initials: X
authors.lastname: He
authors.forename: Xuesi
authors.initials: X
authors.lastname: Wan
authors.forename: Donghong
authors.initials: D
authors.lastname: Fang
authors.forename: Yanbing
authors.initials: Y
authors.lastname: Li
mesh_terms: D005492:Folic Acid / Q000008:administration & dosage*; D006801:Humans; D007004:Hypoglycemic Agents / Q000009:adverse effects* / Q000627:therapeutic use; D008687:Metformin / Q000009:adverse effects* / Q000627:therapeutic use; D014805:Vitamin B 12 / Q000097:blood*
chemical_list: D007004:Hypoglycemic Agents; D008687:Metformin; D005492:Folic Acid; D014805:Vitamin B 12