The idea that children growing up on farms may be less likely to develop allergies and asthma is not new. People have made anecdotal observations about the healthiness of farm kids relative to their urban counterparts for years. But a new study from VIB (a Belgium-based life sciences institute) is the first to find a causal relationship between farm life and allergy resistance. The discovery could potentially lead to the development of an asthma vaccine, the researchers claim.

The key, it turns out, is a special kind of dust. Testing on mice, researchers at VIB found that exposure to "farm dust" helps build resistance to other dust-based allergies—including house dust mite allergy, the most common cause for allergies in humans—as well as asthma. The study, published in the journal Science, also found that a specific protein, called A20, was at the heart of farm kids' increased allergy resistance. 

A20 is a protective protein in the mucous membrane of the lungs which reduces the body’s response to allergens. Breathing in farm dust, scientists found, causes the lungs to produce more A20. This, in turn, reduces allergic reactions to other kinds of dust. The scientists assessed 2000 children growing up on farms, and found that most of them were protected from allergies.

Unfortunately for city dwellers prone to sneezing and wheezing, just going to a farm and breathing deeply won’t alleviate allergies; the resistance is created while the lungs are still developing. But don’t despair just yet. While much more research is still needed, Hamida Hammad, one of the researchers on the study, says, “Discovering how farm dust provides this type of protection has certainly put us on the right track towards developing an asthma vaccine and new allergy therapies. However, several years of research are required still before they will be available to patients.