Diabetes Self-Management Blog

Research has shown that people who take the oral Type 2 diabetes medicine metformin may be at risk for developing vitamin B12 deficiency. Now, a new study indicates that supplementation of this vitamin at the recommended levels may not be enough to address the deficiency. Metformin is believed to be the most commonly prescribed diabetes medicine in the world, with over 48 million prescriptions written in 2010 in the United States alone.

Vitamin B12 serves a variety of purposes in the body, including playing a role in metabolism, as well as in the function and development of the brain, nerves, and blood cells. Symptoms of vitamin B12 deficiency include weakness or tiredness, rapid heartbeat, pale skin, easy bruising or bleeding, and stomach upset. If not corrected, B12 deficiency can damage the nerve cells, causing symptoms such as tingling and numbness of fingers or toes, difficulty walking, and depression.

To determine the relationship between metformin use and vitamin B12 deficiency, and to assess whether supplementation with this vitamin could correct deficiencies, researchers looked at data from the National Health and Nutritional Examination Survey (NHANES), which was conducted in the United States between 1999 and 2006. Information on roughly 1,600 adults age 50 and older with Type 2 diabetes and 6,900 adults age 50 and older without Type 2 was included.

The researchers found that B12 deficiency was present in 5.4% of people with diabetes who were taking metformin, compared to 2.4% of people with diabetes not taking metformin and 3.3% of people without diabetes. They further noted that use of supplements containing B12 was not linked with a reduction of B12 deficiency in people with diabetes, compared to a two-thirds reduction in deficiency among people who did not have diabetes. It is currently recommended that people 50 and older consume 2.4 micrograms of vitamin B12 daily from either fortified foods or supplements.

According to study author Godfrey P. Oakley, Jr., MD, MPSM, “It is important to conduct further research to learn how much B12 is needed to correct the deficiency and to determine whether or not raising serum B12 levels improves the clinical picture for persons taking metformin who have low serum B12 concentrations.”

If you think you may have vitamin B12 deficiency, be sure to speak with your doctor before adding any form of supplements to your health-care regimen.

For more information, read the article “Research Claims That Diabetics Should Take More Vitamin B12 Daily” or see the study’s abstract in the journal Diabetes Care. And to learn more about the association between metformin and vitamin B12, see the posts “Metformin and Risk for Vitamin B12 Deficiency” and “Metformin and B12″.

POST A COMMENT       
  

Comments
  1. Thanks for bringing this to people again! With the problems constantly in the medical news about Vitamin B12 deficiency causing this and causing that, we need to have this as a constant reminder. And, yes, there needs to be more research for those people that are deficient in B12 and having problems in absorbing B12. What is the correct dose and what are the available application methods other than tablets. None of this has been answered in the last decade.

    Posted by Bob Fenton |
  2. I ask the same question as the comment above.

    What is the correct dose to take B-12 supplements either in pill or another application.

    This is a very important fact people with Type II Diabetes need to have.

    My doctor does recommend B-12 supplements but he did not give me a dose level to take.

    Sure would be great if we can find and/or receive an answer to our question.

    Thank you

    Posted by sh |
  3. Thanks for your questions. According to the Institute of Medicine (IOM), the recommended daily allowance for vitamin B12 for people ages 14 and older is 2.4 micrograms daily. (Recommendations are slightly different for pregnant and lactating women.) As noted in the article above, in people age 50 and older, the IOM recommends that B12 be consumed from either fortified foods or supplements. Currently, these recommendations are not any different for people with diabetes.

    With regard to forms of supplements, B12 is available in both pill form and in injections.

    For more information on vitamin B12 dosing, please see this page from the Mayo Clinic:

    http://www.mayoclinic.com/health/vitamin-B12/NS_patient-vitaminb12/DSECTION=dosing

    Sh, I would be sure to let your doctor know that you are thinking about adding a vitamin B12 supplement to your regimen and to speak with him about what dose of B12 he recommends for you, since needs may vary from case to case.

    Thanks for your interest in Diabetes Self-Management!

    Best,
    Diane Fennell
    Web Editor

    Posted by Diane Fennell |
  4. How do you determine how much Vitamin B12 you are getting, without taking a supplement ?

    Posted by Nora M. Miller |
  5. What about what I call “real food” sources of B12, rather than pills or chemical supplements alone? Thanks.

    Posted by Bud Nason |
  6. This is interesting. In addition to various B vitamins since developing type 2 (and being placed on Metformin) I have also been found to be extremely deficient in Vitamin D and Iron. This sespite the fact that I eat a healthy, balanced diet and take daily multivitamins. I’m wondering if there may not be a connection between not just Metformin, but diabetes in general and insufficient absorption of any number of nutrients?

    Posted by Joe |
  7. Hello, Can you tell readers how much B-12 a person on Metformin should have? I would like to know because I stopped taking my multi vitamin a few months ago and I take Metformin for diabetes 2. Thank you, Rose

    Posted by Rose |
  8. what foods contains the vitamin B12?

    Posted by Eula |
  9. I think some may have missed this very informative sentence in the article above — “They further noted that use of supplements containing B12 was NOT [emphasis mine] linked with a reduction of B12 deficiency in people with diabetes, compared to a two-thirds reduction in deficiency among people who did not have diabetes.”

    It would be nice if they’d specified whether or not the supplementation was oral or injected. That might make a difference.

    This finding re: B-12 not being all that helpful for those on Metformin does disappoint me. My diet is pretty healthy, if I do say so myself, but I’ve been taking B-12 for about 10 years, shortly after I read of the relationship between Metformin and it. Guess I’d better have it tested.

    Joe, I’ve wondered the same thing, though not about just the absorption of nutrients, but also the production of them. My Vitamin D level was very, very low even though I take also a multi-vitamin and lived in AZ where I certainly got plenty of sunshine!

    I wish they’d hurry up and discover all that we need to know about Type 2 so that we could actually do the right things! It gets discouraging to hear that being careful to keep blood glucose levels in a good range isn’t the solution to so many of the risks relating to this problem. :) Makes me think I should just give in to temptation and have that bunch of brownies!!

    Posted by marcie |
  10. Very interesting article. When I was taking the oral diabetes medicine Metformin about eight years ago, I would feel weak at times even though I was eating. My doctor never had mentioned about taking a vitamin B12 supplement. The biggest scare was when I had pasted out while driving along on a less busy highway. I was unaware that I was out until I had come to and hit an intersection sign post. Luckily, I’m glad that I wasn’t killed or seriously injured, and no one else had gotten injured or killed. Witness were saying my car was going back and forth between lanes on the road. I no longer take Metformin; I’m now taking insulin. I do keep hard candy on me in cases I do experience blood sugar lows. I’ve lived to tell about my unforgettable experience after taking the diabetes drug Metformin.

    Posted by Kim |
  11. I learned about the fact that Metformin can deplete one’s B12 levels over a year ago. I asked my doctor to check my levels and they were considerably low. I started on Methylcobalimin which is the active form of B12 at that time and started on 1,000 mcg in the am and pm. We did more testing later and while my levels were up they were not up enough. Also we noticed that my homocysteine levels were high. I then changed to Metanx which has the active forms of B12, B6 and Folic Acid. I take one pill in the morning and one at night. My levels have come up into the high normal levels and my neuropathy has improved immensely. I do have flare ups when i eat anything with corn or any byproduct of corn such as absorbic acid, dextrose, baking powder, etc.
    I think it is important for all patients if they are on Metformin or some form of Metformin to have their B12 levels checked especially if they are suffering from symptoms of neuropathy as if low B12 levels are the cause of the neuropathy, finding out and then taking the active form of B12, Methylcobalimin should help greatly, but the important thing is to get tested for low B12 levels first.

    Posted by Kathy |
  12. Most commercial vitamins are inefficient at
    delivering the product so the body can use it
    properly.

    Some vitamins need certain enzymes for the
    body to process them. Others work better if
    taken as a liquid instead of pill form. I
    currently take Vitamin B12 for Neuropathy in
    liquid form.

    Now that I know the fact about metformin
    causes symptoms such as tingling and numbness
    of fingers or toes, difficulty walking, and depression, I understand what has been
    happening to me. I took Metformin for 10 years
    before I stopped and tried to go with diet and
    exercise. It worked for a while, and now I know
    why I had such a dramatic improvement in my
    general well-being once I stopped taking
    metformin, and why my Neuropathy got so bad
    while I was on it. Thank you so much for giving
    us this information!

    I currently take Vitamin B12 Drops I get from
    my chiropractor. It helps a lot with the pain
    from neuropathy. I take it about 4 times a day
    when the pain gets bad. Within 15 minutes
    there is some relief.

    Posted by J. White |
  13. Vitamin B12 is water soluble. Hence excess dosage will not be an issue.
    https://en.wikipedia.org/wiki/Vitamin_B12#Recommended_intake

    Posted by 4thaugust1932 |
  14. Hi Joe,

    I think you posted on my cereal posting this week. Just an FYI that vitamin D and iron deficiency are linked with celiac disease. This may be something that you’ve already looked into, but it might be worthwhile revisiting this with your physician.

    Posted by acampbell |
  15. Hi Bud,

    Check out the NIH Office of Dietary Supplements’ Fact Sheet on vitamin B12 at http://ods.od.nih.gov/factsheets/vitaminb12. This provides a listing of food sources of B12. Note that some people are unable to absorb adequate amounts of B12 from food due to conditions like pernicious anemia and lack of intrinsic factor (common in older adults). For these reasons, B12 must be given in an alternate way, such as by injection, intranasally, or sublingually (under the tongue).

    Posted by acampbell |
  16. Wow! The article and this discussion are mind blowing. I’ve had Type II for 15+ years and have been taking an oral cocktail of medications, whose foundation is Metformin. Over the years, a general sense of tiredness/fatigue has been increasingly present. This mysteriously (sic) often occurs on my way to work despite a good breakfast and controlled sugars. Note: I often take my medicines before leaving! Sometimes, the weakness is so prevalent that I need to rest on the way.
    Also, peripheral neuropathy has been progressing in both my feet so that I am in constant pain and danger because the multiple sensations I experience are confusing (a combination of numbness, tingling, itching, excessive warmth or excessive cold and/or no feelings at all. In the past year I have begun taking Metanx but without truly understanding it’s function. I am going look into Vitamin B deficiency and tract down dosing guidelines. Recently, I was told that I have low levels of Vitamin D. I largely chalked this up to the recent “popularity” of finding this deficiency as contributor to many, many symptoms. Sometimes, I forget how one prescription effects another and the correlations to physical ailments are not always explained well (note: understatement!). So thanks to Diabetes Self-Management for publishing this article, and to all of you have expanded the discussion and made me more aware of the side-effects of Metformin.

    Posted by DS |
  17. At last, I have worked this out for myself and told my doctor a year ago, Yippee, its magic to know that you work has proved correct!
    Yippee!

    Posted by Rogerinfrance |
  18. Well i am so glad i know why i am tired and depressed now. i will have my B12 checked.
    I am also loosing my hair and my nails are wavy looking sometimes. Anyone know what that may be.

    Posted by Linda |
  19. iN AN ARTICLE PUBLISHED IN THE “BOTTOM LINE”.
    YOUR b12 LEVEL SHOULD BE TESTED ANNUALLY, JUST LIKE YOUR CHOLESTEROL AND GLUCOSE. tHE BEST TEST IS THE SERUM b-12 IN THE BLOOD. iT COST LESS THAN $100.00 AND IS COVERED BY INSURANCE. ANOTHER USEFUL TEST FOR b-12 DEFICIENCY IS THE URINARY METHYLAMLONIC ACID TEST OR MMA. THERE IS STILL CONTROVERSY ABOUT WHAT LEVEL OF SERUM ( BLOOD) B-12 IS NEEDED. HOWEVER IT IS WELL DOCUMENTAD IN MEDICAL LITERATURE THAT SYMPTOMATIC PATIENTS WITH SERUM b12 BETWEEN 2OO pg/mL AND 400 pg/ml actually are B 12 deficient.A LEVEL AT LEAST OF 450 PICOGRAMS PER MILLILITER IS THE MINIMUM REQUIRED. FOR BRAIN AND NERVE HEALTH, A SERUM LEVEL OF AT LEAST 1,000 pg/ml NEEDS TO BE MAINTAINED. IT IS VERY DIFFICULT TO GFET ENDOUGH B12 FROMYOU DIET. b12 DEFICIENT PATIENTS SHOULD BE GIVEN A SERIES OF INJECTIONS –1000 MCG. EVERY DAY FOR SEVEN DAYS, FOLLOWED BY WEEKLY INJECTIONS FO R 2 MONTHS. MAINTENANCE THERAPY TYPICALLY IS AND INJECTION EVERY 2 WEEKS. INJECTIONS ACTUALLY ARE THE CHEAPEST TREATMENT. AND CAN BE SELF ADMINISTERED. A 30 MILLILITER MULTIDOSE VIAL OF A FORM OF V. B12 CALL HYDROXOCOBALAMIN COST AND AVERAGE OF $36.OO AND TYPICALLY IS ENOUGHT TO TREAT THE PATIENT FO ONE YEAR WITH MICROFINE NEEDLES. AFTER A YEAR, B12 LOZENGES ARE AVAILABLE IN DOSE 2,000 MCG. DAILY. TAKING ORAL B12, ONLY AABOUT 1 PERCENT IS ABSORBED. iF YOU ARE TAKING PRISOSEC OR ACID SUPPRESSING DRUGS FOR LONGER THAN BOX RECOMMENDED, YOU SHOULD ALSO HAVE YOUR B12 TESTED AND MONITORED. ALZHEIMERS DISEASE AND DEMENTIA PATIENTS ACTUALLY ARE SUFFERING FROM A B12 DEFICIENCY.

    Posted by Linda |
  20. Thank you for your information about B12 and Metformin. I will discuss this with my doctor. Do you have information on if this will affect or cause ED in men.

    Posted by R. Andrews |
  21. My doctor prescribed metformin for my type 2 diabetes but I am afraid to take it because I have intrisic factor pernicious anemia which means that I cannot absorb B12 from food. I have to take monthly B12 injections for the rest of my life. I found all of this out when I ended up in the hospital with blood clots in my legs, lungs, heart and an artery to my left arm. This was all caused from having a B12 deficiency that caused my homocysteine levels to increase. I am OK now but I am afraid to take anything that is going to mess up my B12 levels again. After reading this, I think I need to talk to my doctor again to see if this is really the best choice for me. How exactly does metformin deplete B12? Does it stop you from absorbing it in your food? Maybe I should talk to my pharmacist.

    Posted by Brenda |
  22. Hi,
    Last week I had lots of blood tests done, in particular Vit D and B12. On Monday 8th Oct 2012, results of V D was extremely low level of 29. This level is at Rickets level and other bone disease. My B 12 was 150, which is low as well. Dr sent me for blood test of my Intrinsic Factor gastric, in which I am awaiting results. Dr put me on 1000units of Ostelin twice daily for Vit D problem. The blood test in question is looking for Pernicious anemia, which is an auto-immume disease. Mostly in women and runs in families. Also I am a type 11 diabetic with good glucose levels and the Dr took me straight off Metformin. So now I will be more vigilant with testing my blood each day. I have never had these tests before. If Dr’s know that Metformin can cause these problems of low B12 levels, why aren’t all diabetics informed of this and have yearly B12 blood tests done. To Brenda above, just google pernicious anemia etc and you will find out what happens, also B 12 deficiency and the correlation. I really do not want an auto immune prob, as I already have serious heart blockages due to type 11 diabetes, which cannot be stented (angioplasty) only open heart surgery. Diabetes is very insidious and I did not at first give it the respect it deserved 8 years ago, Thanks Monica

    Posted by Monica |
  23. I heard about B12 deficiency and its possible association with Type 2 diabetes for people taking Metformin,from letters in Balance magazine. Neither my G.P. or my hospital consultant have mentioned it, despite my symptoms of anemia, very pale skin, tiredness etc. Thanks for the information and the comments.

    Posted by Cynthia Toledano |
  24. My father (76) has been on Metformin for about 10 years. He is a boarderline Type II Diabetic. He has had neuropathy for 8 years and now is in a wheel chair. He has been to over 20 doctors for his feet with no success. His GP said Metformin was not at the root cause of his neuropathy. He has never been checked for B 12 deficiency. I suddenly feel like there might be hope. Does anyone know if getting off Metformin (under doctors care) has reduced their neuropathy of the feet and how long it takes? Any thoughts or information would be highly appreciated. Thanks Jimmy

    Posted by Jimmy Franks |
  25. This is good to know. Luckily I’ve always supplemented with B-12.

    Metformin has also been implicated in accelerating dementia in the aged. I seem to recall that it was due to starving the brain for sugar. I try to compensate by including coconut oil in my diet.

    In spite of the above, I think metformin is a wonderful drug.

    Posted by Iggy Dalrymple |

Post a Comment

Note: All comments are moderated and there may be a delay in the publication of your comment. Please be on-topic and appropriate. Do not disclose personal information. Be respectful of other posters. Only post information that is correct and true to your knowledge. When referencing information that is not based on personal experience, please provide links to your sources. All commenters are considered to be nonmedical professionals unless explicitly stated otherwise. Promotion of your own or someone else's business or competing site is not allowed: Sharing links to sites that are relevant to the topic at hand is permitted, but advertising is not. Once submitted, comments cannot be modified or deleted by their authors. Comments that don't follow the guidelines above may be deleted without warning. Such actions are at the sole discretion of DiabetesSelfManagement.com. Comments are moderated Monday through Friday by the editors of DiabetesSelfManagement.com. The moderators are employees of Madavor Media, LLC., and do not report any conflicts of interest. A privacy policy setting forth our policies regarding the collection, use, and disclosure of certain information relating to you and your use of this Web site can be found here. For more information, please read our Terms and Conditions.


Oral Medicines
New Metformin Combo Drug Approved for Type 2 Diabetes (08/13/14)
FDA Approves New Oral Drug for Type 2 Diabetes (08/07/14)
New SGLT Drugs Coming (07/23/14)
Metformin More Effective in African-Americans (07/10/14)

Diabetes Research
Antibiotics Linked to Lows in People Taking Certain Diabetes Drugs (09/11/14)
Low-Carb Diet Benefits Type 2 Diabetes, Heart Health, Studies Show (09/03/14)
Pistachios Offer Protection for People With Diabetes (08/29/14)
New Approach for Neuropathy Pain? (08/18/14)

Diabetes News
Antibiotics Linked to Lows in People Taking Certain Diabetes Drugs (09/11/14)
Low-Carb Diet Benefits Type 2 Diabetes, Heart Health, Studies Show (09/03/14)
Pistachios Offer Protection for People With Diabetes (08/29/14)
New Approach for Neuropathy Pain? (08/18/14)

Diane Fennell
Antibiotics Linked to Lows in People Taking Certain Diabetes Drugs (09/11/14)
Low-Carb Diet Benefits Type 2 Diabetes, Heart Health, Studies Show (09/03/14)
Pistachios Offer Protection for People With Diabetes (08/29/14)
New Approach for Neuropathy Pain? (08/18/14)

 

 

Disclaimer of Medical Advice: You understand that the blog posts and comments to such blog posts (whether posted by us, our agents or bloggers, or by users) do not constitute medical advice or recommendation of any kind, and you should not rely on any information contained in such posts or comments to replace consultations with your qualified health care professionals to meet your individual needs. The opinions and other information contained in the blog posts and comments do not reflect the opinions or positions of the Site Proprietor.


Blood Glucose Self-Monitoring — Part 2: Technique

What Stress Is Doing to Your Brain

Diabetic Cooking: The Summer Issue

Complete table of contents
Get a FREE ISSUE
Subscription questions