According to one article, low B12 (<200 mcg) occurs in 1/2 of non-metformin using diabetics. According to another recent article, “Chronic metformin use results in vitamin B12 deficiency in 30% of patients”. This could eventually lead to B12 deficiency neuropathy which unlike DM neuropathy is treatable.
Endocr Pract. 2009 Nov 26:1-13. [Epub ahead of print]
Vitamin B12 Deficiency is Common in Subjects with Type 2 Diabetes Mellitus Not
Taking Metformin and is Nutritional in Nature.
Jawa AA, Akram J, Sultan M, Humayoun A, Raza R. abstract here
South Med J. 2010 Feb 3. [Epub ahead of print]
Metformin-Induced Vitamin B12 Deficiency Presenting as a Peripheral Neuropathy.
Bell DS abstract here
Several years ago, my daughter, Janice Montbriand, and myself submitted a poster to the Canadian Pain Society on “Commonly Missed Problems in Chronic Pain”. One of those problems was B12 deficiency. In Canada, unlike Europe and the USA, folic acid is added to flour to reduce birth defects. Unfortunately this makes B12 deficiency “pernicious anemia” undetectable because no anemia ever develops with folic acid supplementation. As recent as today, I have lab detected cases of B12 Deficiency with abnormal fatigue and other symptoms undiagnosable without B12 testing. Low B12 can have symptoms of leg pain and numbness indistinguishable from Diabetic peripheral neuropathy.
B12 deficiency is common in Diabetics as a result of their diet. Metformin induces B12 Deficiency further as well.
The above author (Dr. Bell) has contended several disturbing issues re Metformin B12 deficiency:
- “With an absolute vitamin B12 deficiency, it takes twelve to fifteen years to totally deplete pre-existing vitamin B12 stores.”
- “Since metformin has been available for fifteen years in the United States, we may be approaching an epidemic of metformin-induced vitamin B12 deficiency.”
Required oral B12 was in the order of 1500 mcg/day
Comment – this is a wakeup call to physicians and diabetics to have their B12 levels checked yearly while on Metformin.Any comments?