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EXPERT REACTION: Prescription antacids associated with increased risk of allergies

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Medicines prescribed to reduce your stomach acid - commonly used to treat gastric ulcers and reflux - have been associated with an increased risk of developing allergies, say Austrian researchers. The team studied prescription medication records for over 8 million people between 2009 and 2013, finding those people needed stomach acid inhibitors to be twice as likely to need anti-allergy medications in the following years. This was especially prevalent in women and older individuals. The team suggests that because these meds interfere with your stomach acid breaking down food, larger proteins are making it through to the intestines where they can trigger immune responses.

Journal/conference: Nature Communications

DOI: 10.1038/s41467-019-10914-6

Organisation/s: University of Vienna, Austria

Funder: This study was kindly supported by the BGKK (“Burgenländische Gebietskrankenkasse”) and a grant of the Austrian Science Fund FWF, SFB F4606-B28, to E.J.J.

Media Release

From: Springer Nature

Prescription antacids associated with increased risk of allergies

The taking of prescribed stomach acid-reducing medications is associated with an increase in the risk of developing allergies, according to an analysis of over 8 million health records from Austria published in Nature Communications. The findings provide a real-world validation of previous experimental observations.

The immune system is normally tolerant to molecules derived from food and the environment but can become hypersensitive to them in some people, causing allergies. It is currently unclear how hypersensitivity develops, but an increase in allergic diseases in developed countries suggests that changes in lifestyle may contribute. The acidic environment of the stomach helps break down food-derived proteins into small fragments. Stomach acid inhibitors — commonly used to treat gastric ulcers — can interfere with this food digestion. As a result, larger protein fragments reach the intestine, where they can act on the immune system as proto-allergens.

Erika Jensen-Jarolim and colleagues evaluated how much this process may impact public health. They studied prescription medication records covering 97% of the population of Austria over a four year period (2009–2013), and found that people using prescription gastric acid inhibitors were twice as likely to need an anti-allergy medication in subsequent years. Those taking six daily doses per year were at risk, which increased with more frequent usage.  The risk was higher in women, and in older individuals. These findings suggest that the health benefits of gastric acid inhibition must be carefully weighed against potential risks.

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Expert Reaction

These comments have been collated by the Science Media Centre to provide a variety of expert perspectives on this issue. Feel free to use these quotes in your stories. Views expressed are the personal opinions of the experts named. They do not represent the views of the SMC or any other organisation unless specifically stated.

Dr Elena Schneider is a pharmacist by training and works as a NHMRC Research Fellow at the University of Melbourne, Pharmacology & Therapeutics.

Stomach acid plays an important role in breaking down food and absorbing nutrients, as well as also killing bacteria and microbes.

Long-term use of stomach acid inhibitors, used to treat heartburn, reflux or stomach ulcers, disrupt these processes and interfere with food digestion. 

This results in larger proteins getting through the stomach to the intestine where they overstimulate the immune system, which has been shown in previous animal studies and a small group of patients.

For the first time, the authors of this study investigated how much this process actually affects the population by accessing the public health record of almost all Austrians over a 5-year period.

They found that the more often you take stomach acid inhibitors the more likely you are to develop allergies; women are particularly at risk.

Needlessly said, certain people with certain medical conditions need their appropriate therapy for long-term acid suppression, but the majority of people with heartburn and reflux should not be using these drugs long-term. 

Last updated: 31 Jul 2019 11:48am
Declared conflicts of interest:
None declared.
Professor Nikolai Petrovsky is from the College of Medicine and Public Health at Flinders University

An interesting retrospective study showing that subjects taking long term gastric acid suppressant medications were approximately twice as likely to subsequently take anti-allergy medications.

This effect seen with long term gastric acid suppressant medications was stronger in women than in men.

As always, data from non-controlled retrospective studies needs to be treated with caution, as it cannot be used to establish a causal link.

Nevertheless, this study highlights the extremely large percentage of the population taking such gastric acid suppressant medication, raising the question of whether these medications are being overused.

The association was seen with courses of gastric acid suppressant medication as short as six days, which implies if this effect is real then it must be able to work extremely fast.

As the postulated mechanism is the prevention of breakdown of allergens in food in the absence of gastric acid, it might be expected that the increase in allergies should be restricted to oral allergies, such as nuts or shell fish, and not other allergies, such as to insect stings or aero-allergens.

Unfortunately this study was unable to extract such data, with this being a major limitation in its design.

Last updated: 31 Jul 2019 11:46am
Declared conflicts of interest:
None declared.

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