Martha Cooper/National Geographic/Getty
What’s behind the rise in allergies?
Cleanliness is next to godliness, as they say, so for those who are a little less fastidious, the idea that dirt could protect from allergies might have a certain appeal.
First proposed in 1989 by epidemiologist David Strachan, the thinking behind this “hygiene hypothesis” was that modern life has become more hygienic, leading children to catch fewer infections. This somehow predisposes them to develop allergies, perhaps because their immune systems have been incorrectly trained. If so, allergies are the price people in developed nations pay for massively reduced infant mortality.
Read more: The allergy explosion
Allergies are on the rise – and you might even be affected by one without realising. So how can we best deal with the allergy explosion?
It is an idea that caught hold with the public, but it doesn’t fully add up. We now know that childhood infections don’t seem to make you any less likely to develop allergies. And major cities like London and New York had largely cleaned up their acts by 1920 – long before the idea was put forward. Water chlorination and separate sewage systems made cholera and typhoid infections rare. And if clean living is to blame for allergies, it doesn’t make sense that it took 40 years for asthma to begin to rise. Since 1960, developed countries have seen only minor changes in hygiene, so what prompted the sudden and recent surge in food allergies?
What we do know is that older siblings are more likely to get some allergies than younger siblings, and that children who grow up in big families…
