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Metformin, Antacids and Vitamin B12: What Long-Term Medicines Can Change

Team Niroza20 Oct 20264 min read

Lots of people take metformin for diabetes or a tablet for acidity every single day. These medicines do important work, and you shouldn't stop them. But taken for a long time, some of them can lower how much vitamin B12 your body absorbs. Here's what to know.

Metformin

Metformin is one of the most widely used medicines for type 2 diabetes. The US National Institutes of Health (NIH) says it might reduce how much vitamin B12 you absorb and can noticeably lower B12 levels in the blood.

Acid-reducing tablets

The NIH explains that proton pump inhibitors (like omeprazole and lansoprazole) and H2 blockers (like cimetidine) can get in the way of absorbing B12 from food. Why? Your stomach needs acid to free B12 from food. Less acid over a long time can mean lower B12.

Other medicines

The UK's National Health Service (NHS) also lists some anticonvulsants among the medicines that can reduce B12 absorption.

What this means for you

Keep taking your medicines. Don't stop or change anything prescribed without talking to your doctor.
Ask about a B12 test. If you've been on metformin or acid tablets for a long time, ask your doctor whether a check makes sense.
Know the signs. Tiredness, pins and needles, a sore red tongue or memory trouble are worth mentioning. Read more about the signs.
Share your full list. Tell your doctor and pharmacist about every medicine and supplement you take.
Vegetarians, take note. If you eat little dairy and also take these medicines, both can push your B12 down.

Tingling feet: is it diabetes or B12?

If you have diabetes and get pins and needles in your feet, it's easy to blame your sugar levels. The UK's medicines regulator, the MHRA, says tingling can be a sign of low B12. But diabetes itself or other health issues can cause it too. A blood test may be needed to find out which.

In 2022, the MHRA called low B12 a common side effect of metformin. It may affect up to 1 in 10 people who take it. The risk is higher with bigger doses, longer use, older age and diets low in B12. It advised doctors to consider checking B12 from time to time in people with these risk factors. It also said you can keep taking metformin while low B12 is being corrected.

Which acid tablets does this mean?

Proton pump inhibitors are the tablets many people take every day for acidity. Their generic names usually end in "-prazole", like omeprazole, pantoprazole, rabeprazole, esomeprazole and lansoprazole. Check the generic name printed on the strip.

Not sure what you're taking? Show the strip to your pharmacist. If you've been on one for months, ask your doctor at your next visit whether you still need it.

The short version

Long-term metformin and acid tablets can lower vitamin B12.
Don't stop your medicines. Ask your doctor about a B12 check instead.
Vegetarians on these medicines should be extra watchful.

How to judge a nutraceutical brand in India

Plenty of companies call themselves the best nutraceutical brand in India, or even the best healthcare brand in India. Nobody hands out those titles officially, so it helps to judge for yourself. FSSAI rules give you a handy checklist, because these things should be on a nutraceutical label:

The words "NOT FOR MEDICINAL USE".
The amount of each active ingredient, with added nutrients shown as a % of the ICMR daily allowance.
A "Recommended usage" line and a warning not to go over it.
Side effects, warnings and medicine interactions, where they apply.

If a label skips these, or promises to cure a disease (which the rules don't allow), treat that as a red flag.

If your doctor suggests a supplement

Niroza Plant-Based Vitamin B12 gives 2.2 µg of vitamin B12 in 2 veg capsules (as stated on the label). The label suggests 1 capsule twice a day with lukewarm water, or as your doctor advises, for adults over 18. Please don't take more than that, and check with your doctor first if you're pregnant, breastfeeding, on any medicines or have a health condition.

This post is for general information, not medical advice. Niroza products aren't meant to diagnose, treat, cure or prevent any disease, and they don't replace a varied diet.