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.