Recent studies have shown that taking metformin long term can cause low B12 level.
Why should we be concerned with low B12 levels? B12 deficiency can be misdiagnosed as peripheral neuropathy, a possible complication of diabetes where nerve damage from high blood sugars cause numbness, tingling, burning or pain in feet, legs, or hands. Neuropathy is often reversible if caught and treated early but when it can not be reversed, neuropathy can be a very difficult to treat problem.
What does metformin do? Metformin is usually the first medication used for type 2 diabetes because it works well and is generic. Metformin works well to help make your muscles more sensitive to insulin and also helps keep your fasting blood sugar in target by controlling the sugar output from the liver. However, as we know, every medication has side effects. Initially the problems are usually diarrhea and stomach upset. These side effects can be minimized by starting at a low dose and gradually increasing, and by making sure to take metformin with food. The side effect of metformin that is less well-known is that it interferes with your body absorbing B12. Our body needs B12 for healthy nerves and red blood cells and if we can’t absorb B12 we eventually end up with nerve damage and anemia.
How does taking metformin cause low B12 levels? Metformin interferes with the absorption of the B12 from your intestinal tract. Low stomach acid, stomach ulcers or h. pylori infection will also interfere with B12 absorption from food because acid is needed to release B12 from the protein foods.
What if I already have neuropathy? Talk to your doctor about B12 and vitamin D levels, and option such as medications for pain. If you get no relief from these simple options, ask about other therapies available, and if you do not find an treatment that works, ask me about LEAP therapy. Although generally indicated for relief from fibromyalgia, IBS and migraines, this nutrition solution has worked for painful neuropathy as well.
What foods have B12? The best sources are calf liver, sardines, snapper, venison, shrimp, scallops, salmon and beef. Unless you are a strict vegetarian, getting enough in diet is usually not a problem. You can eat enough B12 foods but if your body can’t absorb it, you will still become deficient.
Bottom LIne: If you take metformin, don’t stop the medication. Ask your doctor to check your B12 level yearly. If you are low your doctor can recommend an appropriate treatment or supplement of B12. While you’re at it ask for a vitamin D check also. A simple blood test can save you much more complicated problems down the road.