The so-called “hygiene hypothesis” isn’t really as new as you might think but it did enjoy a newfound audience thanks in large part to a German study that came out right about the time that many Americans were just discovering the power of the internet. You can imagine what happened next.
Comments like “keeping your house. . .germ-free may be giving your kids diabetes” began popping up in online forums and, in recent years, parenting blogs. Are these the ramblings of want-to-be experts or do they represent valid science-based ideas? Let’s find out.
Handwashing is Still Important
For more than 100 years, handwashing has been universally accepted as the best way to prevent infections. And science has study after study proving that this simple practice dramatically reduces death rates from preventable diseases when handwashing programs are implemented in areas where sanitization was previously lacking.
But, and this is a big “but”, science has also long recognized that human beings need a certain level of germ exposure to develop healthy immune systems. So where should we draw the line? Can you actually be “too clean”?
Crackpots & Pseudo-Science–Enter Stage Left
You need only spend a few minutes on any of the online forums catering to the “alternative” crowd to find posting after posting about the “government conspiracy” and “big business pollution” that’s causing asthma rates to rise among children in this country. And, of course, there’s the anti-vaccine, anti-convenience food, anti-you-name-it crowd that claims that all we really need to do is throw out those bottles of bleach and let our children run naked outdoors every day.
But let’s come back to Earth for a moment. How many of us really run through our homes spraying everything in sight with a hospital-grade disinfectant? I don’t know anyone who does that I’m willing to bet that you don’t either. So where does that leave us? Well, as it turns out, this issue is far more complicated than most people realize.
Asthma Rate Are Rising
Asthma rates are rising; this is true. And it’s also true that asthma affects people of all ethnic and economic backgrounds. But asthma is still more common among the poor. If cleaning products and better hygiene was really to blame for rising asthma rates, we should see asthma skyrocketing among the people most likely to be in a position to keep their homes cleaner and better protected from environmental pollutants. But we don’t. If you’re poor, you still have a greater chance of being hospitalized with, or dying from, asthma than your wealthier peers.
“But Germ Exposure Is Important”
Scientists have long recognized that a certain amount of “germ exposure” is necessary for the human immune system to develop properly. But a closer look at the studies linking germ exposure (or lack of it) to certain diseases shows that your immune system doesn’t just pick germs willy-nilly. Only specific micro-organisms are linked to specific medical conditions. There’s absolutely no evidence that exposing your child to, for example, the common cold, makes him less likely to suffer asthma, irritable bowel syndrome or any other health condition.
As an example, let’s take a look at irritable bowel syndrome. There’s no evidence that people with a history of cold, flu or other infections suffer any less than anyone else when it comes to IBS. But when researchers in Canada gave animal test subjects a specific type of bacteria, Lactobacillus paracasei, the mice showed remarkable improvements.
So . . . What’s The Answer?
After examining all the science behind this issue, I think it’s clear that it doesn’t make any sense to intentionally expose your child to potentially harmful pathogens. Nor does it make sense to keep your home operating-room clean, either. But, really, only your doctor is qualified to advise you about the health of your child and any unique challenges your family may be facing. Forget online “experts” with cutsey names and no credentials. Talk to your child’s pediatrician for the information that’s appropriate for you.
CDC. (2001). Hygiene of the Skin: When is Clean Too Clean?
National Center for Health Statistics. (1996). National Health Interview Survey 1996.
Verdu, E., Bercik, P., Bergonzelli, G., Huang, X., Blennerhasset, P., Rochat, F., et al. (2004). Lactobacillus paracasei normalizes muscle hypercontractility in a murine model of postinfective gut dysfunction.