Getting Ourselves Dirty May Not Be Such A Bad Thing

A recent article1 in the New York Times claims that getting ourselves dirty may not be such a bad thing. In fact, the article states that our obsession with cleanliness has led us to create sterile environments that are actually detrimental to our immune system. “In studies of what is called the hygiene hypothesis, researchers are concluding that organisms like the millions of bacteria, viruses and especially worms that enter the body along with dirt spur the development of a healthy immune system.” Furthermore, they assert that a lack of exposure may be a contributing cause to allergies, asthma, and autoimmune disorders (ex. Crohn’s, Ulcerative Colitis, Multiple Sclerosis, Lupus, etc).

This news may seem to contradict logic, which leads us to wash regularly to prevent, or at least reduce, our risk of exposure to infectious agents. But, contrary to popular belief, this hygiene hypothesis actually makes a lot of sense. The theory is similar to that of vaccines and vaccinations. A vaccine exposes us to a small amount of an infectious agent. The idea is that this small amount will be enough to mount an immune response without overwhelming our system and making us sick. In this manner, our immune system builds antibodies that will recognize these infectious agents and defend us against them in the future. The same idea applies to environmental exposure of infectious agents. In the words of Mary Ruebush, a microbiologist, immunologist, and author of Why Dirt Is Good, “What a child is doing when he puts things in his mouth is allowing his immune response to explore his environment.” This invaluable experience is essential in protecting us against future infections. It is equally important in teaching our immune system to differentiate between a situation that it can ignore versus one that requires it to mount an appropriate response.

Some researchers go even one step further. They say that not only is exposure to dirt (with its micro-organisms) good for strengthening our immune response, but it may be helpful in preventing certain inflammatory diseases. In fact, according to studies by Dr. Joel V. Weinstock and Dr. David Elliot who researched patients with Multiple Sclerosis, “patients who were infected with the human whipworm had milder and fewer flare-ups over a period of four and a half years.” Dr. Elliot has also observed the positive effects of pig whipworms on Inflammatory Bowel Diseases such as Crohn’s and Ulcerative Colitis. His explanation for these phenomenon is, that these worms interact with certain parts of the immune system that have been associated with autoimmune diseases (diseases in which the immune system attacks itself). Specifically, “a lot of inflammatory diseases — multiple sclerosis, Crohn’s disease, ulcerative colitis and asthma — are due to the activity of Th 17,” he explained. “If you infect mice with worms, Th 17 drops dramatically.”

Although the current research is finding it beneficial to get our hands (and bodies) dirty once in awhile, it is by no means advocating the abandonment of good hygiene. Neither are we! The take home message is that like dirtiness, sterility also comes with a price. So, with regard to hygiene, moderation rather than obsessive germ phobia may be the key.

1 Brody, Jane E. “Babies Know: A Little Dirt Is Good for You” Jan 27, 2009 on page D7 of the New York Times.

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