What to know about B12 and taking metformin for diabetes

Published on: 05/25/2010
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Do you take metformin for Type 2 diabetes?foods with B12

Did you know that taking metformin long term can cause low B12 level?

That doesn’t mean metformin is a bad medication but there are things that should be explained to you when you start taking it. Metformin has helped many people with type 2 diabetes get their blood sugar to goal over the years and it is inexpensive. But every medication has possible side effects right?

We need to understand how our medications work and the pros and cons of taking them. So here’s what to know about B12 and taking metformin for diabetes.

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. As with any health problem, getting nutrients that help heal and fight disease is the foundation. Learn how to decrease foods and ingredients that cause inflammation. Learn what foods you can add to your meals each day and week to reduce inflammation. If you would like help setting up those meals or have more questions about diabetes,  contact me for more information on my programs and services.

What foods have B12?

The best sources are 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 without talking to your doctor.  Have your B12 level checked every 3 years. If your B12 level is low, your doctor can recommend an appropriate treatment or supplement of B12.


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Thanks for visiting my blog!

I’m Karen, a diabetes nutrition specialist who is passionate about fighting diabetes for my clients, my family, and myself.

I hope you find food ideas and answers to some of your questions here in my articles. But if you are looking for more personalized help with nutrition or diabetes please check out my services page.

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