A study by researchers at Duke University Medical Center provides more support for the "hygiene hypothesis," the notion that people who live very hygienically are more prone to allergies and autoimmune disease because their immune systems were not exposed to, and therefore not challenged by, common microbes in the environment.
The study compared the immune systems of wild house mice and common rats -- routinely exposed to microbes and parasites -- to laboratory mice and rats, which are raised in a virtually germ-free environment.
The researchers looked at the animals' production of certain antibodies, called immunoglobulins (Ig), which are associated with autoimmune disease or allergy. Antibodies are produced by the immune system to bind to intruders and destroy them.
The wild animals were found to have higher levels of IgG -- involved in autoimmune disease -- and IgE, which fights against parasites and has been linked to allergies in humans, than the lab rodents. The wild rodent also had higher levels of a type of IgG called polyreactive, autoreactive IgG, which has been linked to autoimmune disease in both hygienic humans and rodents but did not appear to be affecting the wild rodents.
The finding show that the environment has profound effects on the production of IgE and autoreactive IgG, researchers said. Because autoreactive IgG is able to bind to environmental antigens in the wild rodents, they don't appear to cause harm.
In hygienic animals, however, autoreactive IgG can bind to the body's own cells, which can lead to autoimmune disease. Similarly, IgE can bind to parasites in wild animals, while in lab animals the antibodies bind to harmless environmental antigens, triggering allergies to those substances.
It's estimated that 50 million Americans have allergies and 8 million have autoimmune disorders, which involve an overactive immune system attacking body tissues.
This is continued evidence for the hygiene hypothesis, which states that -- in today's neurotically antiseptic culture -- children's lack of exposure to common bacteria and viruses actually causes health problems later on in life.
It only takes common sense to figure out why the hygiene hypothesis is so valid: a child's body needs "practice" to build up its natural immunities to a range of diseases. That "practice" is a certain amount of exposure to dirt and the bacteria, viruses and more found in it, and yes, occasionally catching a few bugs.
If children are shielded from this, and instead kept in the sterilized indoors and constantly showered in antibacterial soaps and the like, parents may be doing them a serious disservice ... they are not allowing the children's natural defenses to grow and prosper.
Unfortunately, while there are changes people can make in this respect for their kids, adults who were raised in our way-over-sterilized culture do not have the same capacity to allow their bodies to form natural defenses against viruses, bacteria and allergens.
As a result most adults are far more susceptible to health issues from bacteria, viruses and allergens in the air and in dust than they should have been if their natural defenses were allowed to develop naturally. As a result, for example, some 50 million people suffer from allergies in the <st1:country-region w:st="on"><st1:place w:st="on">United States</st1:country-region> alone and allergies in general are growing at a far faster pace than anytime in history.
So whether you already have allergy or other issues related to toxins in the environment, or you want to prevent them, how do you best protect yourself now?
One solution I strongly urge you to consider utilizing -- perhaps the most effective preventive against allergens in your home -- is a high-quality air purifier. However, be very careful. I have had a large allergy part of my practice for nearly 15 years and have carefully looked into this area. My conclusion is that there are many good ones out there but there is also quite a bit of confusion.
If you are interested in this topic you might want to review the report I put together on air purifiers.