Hygiene hypothesis

I have been talking about allergies and asthma for many years now. As you might recall, I wrote a whole book about it. And in that book, I talk about the role that too much cleanliness can play in allergy and asthma development.

The simple fact is that getting dirty is good for you. It stimulates your immune system in ways that we’re only beginning to discover. And I’m glad to see ongoing studies looking into this relationship.

So let’s try this one on for size: Researchers recently discovered that parents who suck on their baby’s pacifier to clean it might be unwittingly protecting their kids against allergies.

That’s right. These children were less likely at 18 months to have symptoms of asthma, eczema, and allergen sensitivity than kids whose parents opted for the sink instead. And this protective effect lasted as long as three whole years.

After adjusting their results to account for things like the mother’s education and mode of childbirth, researchers came up with an even more compelling argument against excessive sterility.

They discovered that parents who birthed their children vaginally were more likely to suck on their babies’ pacifiers than parents who birthed by cesarean delivery. And vaginally born children who were also exposed to parents’ “germs” had the lowest eczema rates, at just 20 percent. (That’s compared to 54 percent among cesarean-born babies who weren’t exposed to parents’ mouth bacteria.)

Some interesting findings, to say the least. And they suggest that exposure to microbiota from mothers’ mouths and the birth canal may have a lasting positive effect on infants’ own population of healthy bacteria.

Which, again, brings us full circle back to the vital role that bacteria play in our lives.

I have to say, as a doctor who focuses heavily on allergies, I’ve long noticed a relationship between eczema and asthma. I’ve always postulated that they’re just two inflammatory conditions with different forms of expression.

But now that I see this study, I’m wondering if their connection may be deeper. And if the body’s bacterial environment isn’t somehow the common thread. It would seem so, at least.

At any rate, bacterial transfer at a very young age appears to strengthen a child’s immune system. Which means that cleaning all of those bacteria away is not a good thing. And it may even be harmful

It makes a lot of sense, when you think about it. This phenomenon occurs in almost every other species. Why do we think we are any different than the other animals on this planet?

Maybe if we embraced our “wild” side just a little bit more, we wouldn’t be bothered by so much disease.

Pacifier cleaning practices and risk of allergy development. Pediatrics. 2013 Jun;131(6):e1829-37.