By Katherine Martinko / Source: TreeHugger

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New research confirms the ‘hygiene hypothesis.’ Farm kids are less likely to develop allergies and asthma than the average child.

Kids need to get grubby on a regular basis. Not only does it mean they’re playing hard while getting exercise and fresh air outside, but it also boosts their immune systems and ultimately makes them healthier.

For years, the ‘hygiene hypothesis’ has been the leading explanation for why so many kids develop allergies and asthma. This hypothesis suggests that kids are being raised in such sterile environments, without sufficient access to dirt and germs, that their immune systems are not trained to recognize which irritants are harmful and harmless.

New research, published in Science, supports this hypothesis and develops it further. A group of Belgian researchers from Ghent University found an actual link between farm dust and protection against asthma and allergies. Children who grow up on dairy farms are much less likely than the average child to develop asthma.

Bart Lambrecht, a study author and professor of pulmonary medicine, explains: “We did this by exposing mice to farm dust extract from Germany and Switzerland. These tests revealed that the mice were fully protected against house dust mite allergy, the most common cause for allergies in humans.” (The Guardian)
The researchers found that there is a protein called A20 that is produced by the body when it comes in contact with farm dust. When A20 was selectively deactivated in mice, the mice were unable to reduce an allergic or asthmatic reaction to the dust.

The study went on to assess 2,000 people who grew up on farms, most of whom had no allergies or asthma. In the few who showed sensitivity, there was a mutation that produced a malfunctioned form of A20. Says Lambrecht, “Those who are not protected and still develop allergies have a genetic variant of the A20 gene that causes the A20 protein to malfunction.”

While it’s still unknown what the active substance is in farm dust that actually creates the protection, the researchers are hoping to develop an asthma vaccine and allergy therapies once they know more.

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