Why Do People Have Allergies?

John Bottrell Health Pro
  • So if allergens such as dust mites, molds, fungus, animal dander, cockroach urine, pollen and ragweed are supposed to be safe for people, then why do people get allergies?  What's the deal?


    Dr. Paul M. Ehrlich, in his book, "Living with Allergies" (2009, page 6), describes an interesting theory.  He explains that allergies are "a leftover survival tactic" whereby ancient people living along the Tigris and Euphrates Rivers were repeatedly exposed to harmful germs such as bacteria and parasites.


    This is easy to immagine considering people lived outdoors, were in close contact with animals, water, and ate uncooked foods. 

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    Years ago, Ehrlich explains, immune systems needed to be powerful to fight off such germs.  People with the strongest immune response survived while others died.  "So being an allergic person may have been an advantage."

    Yet today we have many defenses against such invaders, he explains, such as shoes, clothing, clean drinking water, processed food, vegetables that are treated with pesticides, air conditioned buildings, vaccinations and hand sanitizers.  People today simply aren't exposed to germs, so the allergic response isn't needed.

    For most of us, our immune systems have adapted to the change.  Yet for some of us -- about 10 percent, or 75 percent if you have asthma -- our immune systems continue to work overtime.  Lacking harmful germs to occupy our immune system, it becomes bored and develops a sensitization to your allergens.


    For more theories on why people develop allergies, check out the hygiene hypothesis and microflora hypothesis.

Published On: September 12, 2012