everyone is allergic to peanuts now? Or has some other serious allergy? One explanation is the so-called "hygiene hypothesis," which says that the reason allergies are on the rise is because our super-hygienic lifestyle has reduced our exposure to all sorts of microorganisms, both good and bad, and has prevented our immune systems from developing normally.
Now new support for this hypothesis has come in the form of a study showing that children with higher levels of antibacterial and preservative chemicals in their urine have higher incidence of food and environmental allergies. The levels of these chemicals found in the urine reflects the amount of exposure kids have to them, and come mainly from personal products including soap, mouthwash, and toothpaste. More exposure resulted in higher levels of IgE antibodies, involved in the allergy response. Children with the highest levels of exposure to Triclosan, one of the antibacterial agents studied, had twice the risk of peanut and environmental allergies as kids exposed to low levels of the chemical.
The researchers' hypothesis is not that these chemicals directly cause allergies, but that exposure to them inhibits proper development of the immune system, which leads to development of allergies later. It's a little more support for the idea that, while antibiotics and antiseptics are pretty awesome and have extended the human lifespan enormously, bathing your children in Purell and antibacterial soap every time they go outside might not be the best idea. Let them eat a little dirt next time.
(Image: Untitled, a Creative Commons 2.0 image from ms. Tea's photostream)