Metformin is the most commonly prescribed medication to treat Type 2 or adult-onset diabetes. If you have this condition, your body has lost sensitivity to the hormone insulin, which transports glucose, a sugar, into the cells to be metabolized for energy. Like other medications, metformin may interact with other drugs in your body; in some cases it can interact negatively with certain vitamins. Consult your doctor if you have any concerns. Do not stop or change your dosage of any diabetes medication on your own.
Functions of Metformin
If you have Type 2 diabetes, your doctor likely prescribed metformin as a first line of defense. This medication helps to balance blood glucose levels in three ways. It makes your body more sensitive to insulin so that it can move glucose into your cells more effectively. Metformin also reduces the amount of glucose you absorb from food and the amount of stored glucose released by the liver.
Metformin and Vitamin B-12
A 2006 study published in the "Archives of Internal Medicine" reports that metformin can interfere with the absorption of vitamin B-12 in the body. This interaction can lead to a deficiency of this essential vitamin in some individuals. Vitamin B-12 is central to several bodily processes, including the production of red blood cells. A deficiency can cause anemia and result in poor oxygen circulation, fatigue, dizziness and weakness.
Supplements for B-12 Deficiency
If you are taking metformin, your doctor can test your vitamin levels to determine whether you are at risk for a deficiency. According to "Diabetes Care," the journal of the American Diabetes Association, 10 to 30 percent of patients takin metformin show some signs of reduced vitamin B-12 absorption. Your doctor may prescribe vitamin B-12 supplements to correct any deficiency. "Diabetes Care" reports that calcium supplements can also help raise vitamin B-12 levels.
Additional Vitamin Interactions
Drugs.com notes that metformin may also have adverse interactions with niacin, also called vitamin B-3. Niacin can reduce the effect of metformin on blood glucose levels, lowering the efficacy of your diabetes control. Other vitamins such as vitamin C have not been found to have any interaction with metformin. However, if you have any concerns about interactions between vitamins and your medications, consult with your doctor before you stop taking your medication.
- Archives of Internal Medicine: Risk Factors of Vitamin B(12) Deficiency in Patients Receiving Metformin; 2006
- National Institutes of Health: Metformin
- Drugs.com: Drug Interactions Between Metformin and Vitamin C
- American Diabetes Association: Diabetes Care: Increased Intake of Calcium Reverses Vitamin B12 Malabsorption Induced by Metformin
- Drugs.com: Drug Interactions Between Metformin and Niacin SR