Food and Behaviour Research

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11 Dec 2013 - BBC News - Ulcer drugs linked to vitamin B12 deficiency

People who took tablets known as proton pump inhibitors (PPIs) or histamine antagonists (H2RAs) were more likely to lack enough vitamin B12 for good health.


Medications to 'reduce stomach acid' are not only widely prescribed, but available over-the-counter.  They are used not only for the management of stomach ulcers, but for almost any kind of 'indigestion' or gastric symptoms.

New findings confirm that these drugs can cause Vitamin B12 deficiency if taken for more than 2 years.

Given how serious the effects of untreated Vitamin B12 deficiency can be - and how often B12 deficiency is NOT diagnosed when it actually occurs, even if tested for (as standard serum B12 tests are highly insensitive), these findings need to be widely publicised, rather than downplayed.  See:

Like many drugs, antacids are intended (and were tested in clinical trials) only for short-term use.  Reducing stomach acid can impair the absorption of many other essential nutrients in addition to B12 (including Vitamin C, zinc, iron), as well as leading to other problems with digestion.

For more details of this research study, see:

And for more information on the critical importance of Vitamin B12 for brain health, see:

Medication used to treat stomach ulcers may cause potentially harmful vitamin B12 deficiency, say experts.

A US study of 200,000 people in the Journal of the American Medical Association found the link.  

Left untreated, B12 deficiency can lead to dementia and neurological problems.

The study authors say doctors should still prescribe these medicines, but that they should weigh possible harms against any benefits in patients who need the drugs for prolonged periods of time. 

More investigations are needed to fully evaluate the risk which appears to be in people who take these medications for two or more years, they say.


The Kaiser Permanente researchers found that the link with B12 deficiency increased with dose and was stronger in women and younger age groups.

But the overall risk was still low.

PPIs and H2RAs are commonly prescribed for patients with symptoms of stomach ulcers such as heartburn and indigestion.

The tablets are also widely available to buy without a prescription, 'over-the-counter' at pharmacies.

They work by reducing the amount of acid made by your stomach.

Stomach acid is needed for us to absorb vitamin B12 from our food, such as meat, fish and dairy.

If identified, most cases of B12 deficiency can be easily treated by giving supplements or an injection of vitamin B12.

But symptoms, such as lethargy, can be vague and overlooked.

Prof Mark Pritchard of the British Society of Gastroenterology said people should not be concerned by the findings.

"Only patients who had taken these tablets for more than two years were at risk and only a minority of patients on long-term proton pump inhibitors showed evidence of vitamin B12 deficiency."

He said people taking ulcer medications could ask their GP for a simple blood test to measure vitamin B12 levels if they are worried.