Clean living could be making people sicker

The Washington Post said many allergies and immune-system diseases have doubled and even quadrupled in the last few decades, with more than half of the U.S. population reporting an allergy.

The increases show up mainly in highly developed countries, researchers said. One theory, known as the hygiene hypothesis, blames increased allergies on cleaner homes, increased air pollution and changes in diet. Obesity and lack of exercise may also play a role.

In an effort to counteract the effects of modern living, some scientists are feeding high-risk children small amounts of allergy-inducing foods to train the immune system not to overreact, the newspaper said. A University of Iowa researcher is treating patients with multiple sclerosis and colitis with parasitic worms.

"If you look at the incidence of these diseases, a lot of them began to emerge and become much more common after parasitic worm diseases were eliminated from our environment," Robert Summers told the Post. "We believe they have a profound symbiotic effect on developing and maintaining the immune system."

Copyright 2008 by United Press International