A feature story from the March 19, 2006 issue of USA TODAY documented that exposure to pets, peanuts and intestinal worms may actually be beneficial to children, due to the fact they program their developing immune system to recognise the distinction between real threats and common exposures.
The article begins by noting that this new thinking is opposite of the previous conventional knowledge that said it was best to guard kids from all of these kinds of exposures. They now state exactly the opposite. Dr. Andy Saxon of the University of California-Los Angeles, states, "What we have now learned is that it may well, in fact, be important to be exposed early on to a sufficient quantity of allergy-causing substances to train the body's immune system that they are not really a danger."
In the article Dr. Joel Weinstock of Tufts New England Medical Center added, "When you're born, Day Zero, your immune system is similar to a new computer. It's not programmed. It's important to add software. Between the ages of zero and 12, you're learning how to read, you're learning to write, along with your immune system learning to react to things. A part of that is learning to limit reactivity."
The article explains the new thinking on allergies by what is recognized as the "hygiene hypothesis". This theory indicates that being raised in cities and suburbs, away from fields and farm animals, leaves individuals more susceptible to countless immune disorders including allergies and asthma. To strengthen this point Dr. Weinstock points to the difference between developed nations with urban communities and undeveloped, countries, "Hay fever is the most common allergy in the developed world," he says. "Yet, there are a few countries on the planet where doctors don't know what hay fever is."
The article added further evidence by reporting on a study by Dr. Dennis Ownby of the Medical College of Georgia. In his study Ownby followed 474 infants in the Detroit area from birth to age 7 at the Henry Ford Hospital in the hope of finding clues to why some would pick up allergies and others would not. The scientists on his team found that when they compared 184 children who were exposed to two or more dogs or cats in their first year of life with 220 children who didn't have pets, the children raised with pets were 45% less likely to test positive for allergies than other kids.
The article notes that this new thinking could have a profound effect and help millions. They report that more than 50 million people have allergic diseases, which are the sixth-leading cause of chronic illness in the USA. Additionally, they note that according to the National Institute of Allergy and Infectious Diseases (NIAID), costing the health system $18 billion a year.