Neuropathy, vitamin B12 and Metphormin?

[Reptile]

I have read that metphormin can significantly block the absorption of B12 and that the resulting deficiency can be a major cause of neuropathy. Can anyone confirm this and is it possible to address this with oral B12 supplements?

 

[Lucyr]

If you do have a deficiency caused by metformin blocking absorption then oral supplements wouldn’t help much as metformin blocks the absorption and so it would be treated by injections usually

 

[everydayupsanddowns]

Do you have any of the symptoms of B12 deficiency @Reptile ? Or are you just concerned about the possibility?

If you are worried, it might be worth asking your GP for a B12 check?

 

[Reptile]

Do you have any of the symptoms of B12 deficiency @Reptile ? Or are you just concerned about the possibility?

If you are worried, it might be worth asking your GP for a B12 check?

Mostly concerned about the possibility. I'm taking 2 grams of metformin per day.

 

[everydayupsanddowns]

Mostly concerned about the possibility. I'm taking 2 grams of metformin per day.

As a first line treatment for T2 metformin is very widely prescribed at that level, and while there is an association between long-term use and the possibility of low VitB12, this only affects a fairly small proportion of people (somewhere between 6-30%), so it’s good to be aware of the possibility, but try not to stress too much about it. Just perhaps something to bear in mind if you get some sort of symptoms 🙂

 

[Jenny105]

I have the opposite problem . At the same time as my blood sugar was found to be 96 (Hc1A??) my Vit B was 1400, 2 weeks later 2000. Way over the top.

 

[mikeyB]

As a first line treatment for T2 metformin is very widely prescribed at that level, and while there is an association between long-term use and the possibility of low VitB12, this only affects a fairly small proportion of people (somewhere between 6-30%), so it’s good to be aware of the possibility, but try not to stress too much about it. Just perhaps something to bear in mind if you get some sort of symptoms 🙂

That’s not an an association and here’s why: A low Vit B12 affects about 6% of the general population, rising to 20% or so in the over 60s. Whether you are taking Metformin seems to have no effect on that, then.

 

[everydayupsanddowns]

That’s not an an association and here’s why: A low Vit B12 affects about 6% of the general population, rising to 20% or so in the over 60s. Whether you are taking Metformin seems to have no effect on that, then.

I don’t know - there do seem to be a few papers in the literature, including RCTs

Only briefly skimmed them, but

Long-term Metformin Use and Vitamin B12 Deficiency in the Diabetes Prevention Program Outcomes Study

Participants from DPP/DPPOS were assigned to placebo (n=1082) or metformin (n=1073) for 3.2 years, followed by metformin in the metformin group for 9 years. Metformin use was associated with increased risk of vitamin B12 deficiency.Vitamin B12 deficiency ...

www.ncbi.nlm.nih.gov

Long term treatment with metformin in patients with type 2 diabetes and risk of vitamin B-12 deficiency: randomised placebo controlled trial

Objectives To study the effects of metformin on the incidence of vitamin B-12 deficiency (<150 pmol/l), low concentrations of vitamin B-12 (150-220 pmol/l), and folate and homocysteine concentrations in patients with type 2 diabetes receiving treatment with insulin. Design Multicentre...

www.bmj.com

Association between metformin dose and vitamin B12 deficiency in patients with type 2 diabetes

Supplemental Digital Content is available in the textMetformin can cause serum vitamin B12 deficiency, but studies on the influence of its duration and dose are lacking. We investigated vitamin B12 deficiency in patients with type 2 diabetes using metformin, ...

www.ncbi.nlm.nih.gov

Plus commentary for nursing staff

Metformin use and B12 deficiency: What nurses need to know - Independent Nurse

Margaret Perry explains how to negate the side effects of this commonly used treatment

www.independentnurse.co.uk

 

[mikeyB]

What I was demonstrating is that the frequency of B12 deficiency is the same in the normal population as it is in the folk taking Metformin, or T2s on insulin. Just because it is found in people taking Metformin doesn’t mean it was caused by Metformin. I don’t care how many nurses write papers on how to prevent this or warn against it, it’s fighting an illusion. Just treat it, like you do with everybody who isn’t T2, it’s not rocket science, it’s easy.

This may seen like a trivial argument, but it’s the way insurance companies get out of paying out if the B12 deficiency is discovered while on holiday. “It’s the diabetes”. It’s not.