September 28, 2016
The Amish asthma anomaly
Healthy dust? It may be the answer to one of modern medicine’s puzzles: why the Amish have such low rates of asthma. The mystery dates to a 2012 study which found Amish children have much lower rates of asthma and allergic reactions than Swiss children—a population with extremely similar genetic roots. Now, a new study in the New England Journal of Medicine
appears to reveal the answer to the riddle: house dust. This time, the researchers compared Amish subjects to Hutterites, another American farming community with a deep European lineage. Again they found the Amish had much lower rates of asthma—about ¼ that of the Hutterites. But when they analyzed dust from Amish and Hutterite homes they found the Amish dust had much higher levels of endotoxins. Endotoxins are toxins created when a bacterial cell disintegrates. When the researchers exposed lab mice to the Amish dust, the mice’s airways became much less sensitive to irritants. So, how did the Amish cultivate this amazing biological dust? The researchers think it’s from their old-school lifestyle. In Amish country, kids live closer to barns, near traditional farming equipment like horse-pulled plows. This exposes them to unusual flora- and fauna-borne bacteria—bacteria that loves hanging out in the house dust. Mild exposure to these pathogens could cause human immune systems to develop antibodies and resistance to them. In the immunology world, this is called the hygiene hypothesis, and experts warn it is vastly oversimplified. But it does appear to be helping the Amish breathe more easily. I’m a bit suspicious. I grew up around farms in Kansas, but I don’t care what kind of dust you expose me to: it is 100% guaranteed to trigger an allergy attack.