Attack of the Too-Clean Environment?

March 4, 2008

The Washington Post has an interesting if somewhat frustrating front-page story today about the rise of allergies and immune-system diseases — which experts say have “doubled, tripled or even quadrupled in the last few decades, depending on the ailment and country.”

“Allergic diseases” includes ailments such as hay fever, eczema, asthma and food allergies. Autoimmune diseases include lupus, MS, Type 1 diabetes and inflammatory bowel disease. In addition to varying theories about what’s causing the increase in both, scientists are implementing various methods in an attempt to stem the problem:

The cause remains the focus of intense debate and study, but some researchers suspect the concurrent trends all may have a common explanation rooted in aspects of modern living — including the “hygiene hypothesis” that blames growing up in increasingly sterile homes, changes in diet, air pollution, and possibly even obesity and increasingly sedentary lifestyles.

“We have dramatically changed our lives in the last 50 years,” said Fernando Martinez, who studies allergies at the University of Arizona. “We are exposed to more products. We have people with different backgrounds being exposed to different environments. We have made our lives more antiseptic, especially early in life. Our immune systems may grow differently as a result. And we may be paying a price for that.”

Along with a flurry of research to confirm and explain the trends, scientists have also begun testing possible remedies. Some are feeding high-risk children gradually larger amounts of allergy-inducing foods, hoping to train the immune system not to overreact. Others are testing benign bacteria or parts of bacteria. Still others have patients with MS, colitis and related ailments swallow harmless parasitic worms to try to calm their bodies’ misdirected defenses.

Yes, worms.

While the good-hygiene theory is favored among some scientists, dissenters point to the rise of asthma in poor, inner-city environments as evidence that there must be something else going on.

“That theory is so full of holes that it’s clearly not the whole story,” said Robert Wood of the Johns Hopkins School of Medicine.

The story clocks in at close to 1,500 words — which is nothing to sneeze at — but the topic seems worthy of a magazine-length article, at the very least, and I would love to read more. Maybe you’ve read something more comprehensive on this topic? If so, please share.

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