Backyard Biodiversity May Stem Allergies

05-07-2012 • http://www.livescience.com, Wynne Parry

The study focused on a predisposition for allergies among 118 Finnish teenagers, finding links between a healthy immune system (the body's system for fighting disease), growing up in more natural environments and the presence of certain skin bacteria.

The results support the idea that declining biodiversity might be contributing to the rapid rise in allergies, asthma, and other inflammatory diseases, which include autoimmune disorders and some types of cancers in the developed world, said Ilkka Hanski, a research professor at the University of Helsinki.

This idea — that the diversity of living things, including microbes, in an environment contributes to the development of normal immune system function in children — is called the biodiversity hypothesis. It builds upon the hygiene hypothesis, a theory that suggests exposure to certain microbes early in life helps train our immune systems not to respond to harmless foreign substances like pollen.

The hygiene hypothesis attributes an increase in allergies to a lack of childhood exposure to microbes. Essentially, we have become too clean for our own good, it says. [Infographic: Germs Are Everywhere!]

The more scientists learn about the tiny things that share our bodies — living in our guts, on our skin and elsewhere — the more questions arise about these microbes' role in our health.