A new understanding of allergy evolution influences research

By Amy Mayer • Published: August 3rd, 2012
Category: Health in a Heartbeat

Allergy warnings appear on everything these days. It seems anything could be a threat.

But, the question is, what do shrimp, tree pollen and snake venom have in common? Researchers aren’t quite sure yet, but they say there’s got to be something that links these common allergens. A recent study published in Nature proposes a new perspective on allergies and offers some suggestions. In the past, allergic reactions were understood as an evolution of the body’s defense against macro-parasites — biting insects and spiders, for example, or tapeworms. But these critters supply slow-moving toxins, so extreme reactions such as anaphylaxis — which quickly restricts breathing — seemed outsized.

Researchers from the Yale University School of Medicine offer a new direction in allergy research that challenges this long-held theory about allergies. They say the allergic response may have the added intention of protecting us from environmental toxins.

The scientists purport that in addition to defending against the specific trigger, an allergic response may exist to protect the body from a bad environment. In other words, allergies may have evolved as a screening mechanism to prevent mammals from attempting to inhabit suboptimal habitats.

Birds and reptiles, on the other hand, don’t seem to have the same allergy “machinery.” The researchers cite the body’s allergic reactions — including sneezing, itching and excessive mucus production — as further evidence that the response aims to rid the body of unwanted toxins and prevent the host from staying in an inhospitable place.

Will any of this ease your allergy symptoms? Maybe not right away, but as immunologists deepen their understanding of allergies, advances in prevention and treatment are likely to follow.