Tuesday, March 10, 2009

Allergically Clean?

Are we in the Industrial West breeding generations of allergy sufferers due to our overly hygienic lifestyle?

By: Ringo Bones

Loading one’s home with soaps, hand wipes, and antibacterial detergents has always been a sign of good parenting in the Western world. But ever since that somewhat controversial study on allergies whose data began to emerge near the end of the 1990’s showing that our modern overly hygienic lifestyle may actually trigger a heightened vulnerability to allergies – even to asthma – has sent shock waves across households of the affluent West.

Although some scientists have speculated as far back as the 1970’s that if the human immune system is not exposed to harmful pathogens during childhood, it may develop an over-active immune responses – hence allergies – to harmless plant pollen and mites. If this is true, then are we in the West guilty of breeding a generation of children with immune systems akin to white lab mice, unable to survive unaided in Mother Nature’s wild blue yonder?

A study conducted during the 1990’s by Paolo Matricardi, an immunologist working for the Italian Air Force, has finally found support for the hygiene theory of allergies. While looking for signs of exposure to the three most common food-borne pathogens – namely Toxoplasma gondii, Helicobacter pylori, and hepatitis A – in two groups of 240 male cadets. During the course of the study Matricardi has found out that one group of cadets had elevated allergic responses, while the other did not. The data of the study also shows that allergies were extremely rare – even nonexistent – among those who had exposure to two or all of the food-borne pathogens during their childhood, while allergy incidences were very common to those who had not.

Basing on the results of his study, Paolo Matricardi believes that our body’s immune cells – especially those in the gut – are primed to respond when they first encounter invading bacteria or viruses. Without such “training” during infancy and childhood, our body’s immune cells may instead multiply in response to innocuous – even to relatively harmless – stimuli. Thus giving primary credence to the theory that the main mechanism behind allergies in the affluent West is an overly hygienic lifestyle.

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