HealthHacks

My wife loves her Purell hand sanitizer. She slathers it on anything that has even the faintest possibility of being dirty — doubly so when it comes to something our son might play with. She is not alone: this germophobia seems to be increasingly common. We are ‘antibacterializing’ everything from our soaps to our plastics today.

Ironically, researchers are discovering several diseases, such as asthma, allergies, and eczema, that may be on the rise because of our hyper-sanitation. This idea, known as the hygiene hypothesis, is backed by a hefty amount of anecdotal evidence and several studies.

For example:

• Hay fever is more common in urban areas than in the country.
• Allergies are more common in the Western world than the developing world.
• Allergies increase in immigrants to the Western world.
• A study of East and West Germany just after unification found higher allergy rates in relatively poorer and thus dirtier East Germany.
• Increased infant hygiene is independently associated with higher levels of wheezing and atopic eczema later in childhood.
• Children who received oral antibiotics by age 2 were more susceptible to allergies than children who had no antibiotics.
• Children with dogs and older siblings have lower incidence of allergies.
• Daycare attendance before age 1 is correlated with lower allergy incidence.
• Infection with intestinal worms has been shown to relieve Chron’s disease.
• Hepatitis A exposure — nearly a certainty before 1970, but only in roughly 30% of people today — has been shown to cut the rate of asthma by 75% in susceptible children.

Researchers believe lack of early exposure to these pathogens sets up an imbalance between two types of cells in the immune system: the Th1 and Th2 lymphocytes. The Th1 lymphocytes work by attacking infected cells, while the Th2 lymphocytes work to preventively to stop entry to the body’s cells. The Th2 system creates the familiar allergic response. If the Th1 system gets inadequate training, it is believed, the Th2’s allergic response comes to dominate the body’s immunological defense.

There is a lot more research that needs to be done on the issue, but it is becoming increasingly clear there are unintended consequences to our hygiene obsession.

Does this mean you should quit washing your or your children’s hands? Definitely not. But it does mean you should probably relax and get out more. When was the last time you rolled around in a field? If nothing else, it makes you feel better — and the exercise doesn’t hurt either.

USA Today had a good article on the issue Monday.

Some additional resources here, here, here, here, and here.

[tags]health, allergies, immune system, hygiene hypothesis, asthma [/tags]

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