These common medicines may trigger vitamin B12 deficiency, neurologist warns

Widely used diabetes and acidity medicines may reduce vitamin B12 levels, raising the risk of nerve damage if deficiency goes undetected, doctors caution

If you are taking medicines for diabetes or acidity, there is something important you should know. Experts say long-term use of certain common drugs can interfere with vitamin B12 absorption, often without obvious early symptoms.

 

According to Dr Sudhir Kumar, neurologist at Apollo Hospitals, Hyderabad, vitamin B12 deficiency often creeps in silently as its early symptoms are easy to brush aside. However, if left unchecked, it can cause serious and sometimes irreversible neurological damage.

Why is vitamin B12 essential for the body?

Vitamin B12, also called cobalamin, is not just another vitamin on your supplement shelf. It plays a critical role in keeping your nerve cells and blood cells healthy and is essential for DNA synthesis, the basic blueprint of life.

 

 

Unlike some nutrients, your body cannot make vitamin B12 on its own. You have to get it from food or supplements. Despite this, B12 deficiency is surprisingly common, especially in older adults and people following vegetarian diets.

Which common medicines can lower vitamin B12 levels over time?

According to Dr Kumar, two widely used classes of drugs can interfere with vitamin B12 absorption over time.

 

The first is Metformin, a frontline medication for type 2 diabetes and often prescribed for conditions like polycystic ovary syndrome (PCOS). “Metformin can cause reduced absorption of vitamin B12 in the small intestine,” Dr Kumar explains. The risk rises when the drug is used for many years or at higher doses.

 

The second group is proton pump inhibitors (PPIs), which are the medicines many people take almost casually for acidity, heartburn, or reflux. These include omeprazole, pantoprazole, rabeprazole and esomeprazole. PPIs reduce stomach acid, which is helpful for acidity, but stomach acid is also needed to release vitamin B12 from food. Less acid means less B12 absorption.

Who is most at risk of vitamin B12 deficiency?

Dr Kumar points out that people who have been taking Metformin or PPIs for more than two years are at higher risk. Age matters too. Large surveys from the US and the UK suggest that around 6 per cent of adults over 60 are vitamin B12 deficient, while nearly 20 per cent have borderline levels. The risk increases steadily with age.

 

Vegetarians face an additional challenge. Since vitamin B12 is naturally found in animal-based foods such as meat, eggs and dairy, low intake of these foods can further raise deficiency risk, particularly in developing countries.

What symptoms of vitamin B12 deficiency should not be ignored?

Common symptoms include unexplained tiredness, tingling or numbness in the hands and feet, poor balance, and pale skin. Some people experience nausea, diarrhoea, loss of appetite, weight loss, vision problems, or a sore mouth.

 

More concerning are cognitive and psychological symptoms such as forgetfulness, confusion, irritability, or other psychiatric changes. These neurological effects are the reason doctors urge early detection.

How can you prevent deficiency without stopping essential medicines?

Dr Kumar advises not stopping medications on your own. Metformin and PPIs are effective and generally safe when used appropriately.

 

What Dr Kumar recommends instead is regular monitoring. A simple vitamin B12 blood test every one to two years, especially for those on long-term Metformin or PPIs, can catch deficiency early.

 

“Even if someone feels completely normal, checking B12 levels periodically can prevent long-term damage,” he notes. The good news is that once detected, vitamin B12 deficiency is usually easy to treat. 

 

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This content is for informational purposes only and is not a substitute for professional medical advice.