Taking Metformin? Check your B12 status


A study shows it’s worth checking your vitamin B12 level if you are taking the diabetes medication metformin.

autumn 2017 - taking metformin.jpg

Doctors believe there are many benefits of taking metformin if you have type 2 diabetes but one possible negative effect is that it may impact on your B12 levels, causing deficiency in this important vitamin.

B12 is needed for the healthy function of the brain and nervous system and for energy production but recent research from the global Diabetes Prevention Programme has shown that long-term metformin use may lead to B12 deficiency. Similar results were found in a local Wellington study.

Diabetes specialist Prof Jeremy Krebs commented:

“Metformin can reduce the absorption of vitamin B12. We have published data from Wellington demonstrating relatively high rates of low or borderline vitamin 12 in those with type 2 diabetes who are on metformin. This paper reports similar data from participants of the Diabetes Prevention Programme.

“Although it is uncommon to be associated with anaemia or neuropathy, metformin does increase the risk of these. These data support the call to monitor vitamin B12 status in those on metformin.”

You can ask your GP for a blood test to check your vitamin B12 level. Intramuscular injections are an option if you are severely deficient but sublingual B12 (under the tongue spray or drops) is just as good for maximum absorption.

“We have also published a study showing that sublingual vitamin B12 is as good as intramuscular injections to replace vitamin B12 in those on metformin, and may be more acceptable to those who need it”, Prof Krebs added.

Reference:J Clin Endocrinol Metab 2016; 101(4): 1754–61


Am I at risk?

• You are over the age of 60 – as you get older you are less likely to absorb B12 at optimum levels.

• You are vegetarian or vegan – B12 doesn’t occur naturally in plant-based foods. Some of the best food sources are meat, eggs, milk and cheese.

• You take regular PPI (proton pump inhibitor) medication – such as omeprazole – it impedes B12 absorption.

• You suffer from a digestive issue – people with irritable bowel and coeliac disease are less able to absorb B12 – or have undergone weight loss surgery.

• You have low energy levels – you need B12 to make red blood cells, which transport oxygen throughout your body.

• You have raised homocysteine levels – studies show that insufficient B12 can elevate homocysteine, which in turn increases the risk of heart disease, stroke and pregnancy complications.

Source: betteryou.com


Vitamin B12

Vitamin B12 plays an important role in the functioning of the brain and nervous system, and in the formation of the red blood cells. It is required for energy production in every cell in the body, and in the synthesis of DNA. If left untreated, vitamin B12 deficiency can lead to anaemia, as well as nerve and brain damage which may manifest in symptoms such as brain fog, memory problems, fatigue, depression, muscle fatigue and tingling in the extremities.

If you think you’re at risk, ask your GP for a blood test to check your vitamin B12 level.

*This article first appeared in the Autumn 2017 issue of Diabetes Wellness magazine. Subscribe to Diabetes NZ today to receive your copy.

Jo Chapman