Do Intestinal Parasites Prevent Allergies?

Protecting children from germs too assiduously in their early years may allow the immune system to “tilt” towards developing allergies, according to the hygiene hypothesis. But studies of kids in daycare have been inconsistent. Now an analysis of 21 studies suggests that exposure to intestinal parasites may be the key to reducing allergic reactions later in life
Out of 29,000 people in the studies, those who had hookworm, roundworm or whipworm were 31 percent less likely to react to allergens in a skin test. This study doesn’t prove that parasites protect against allergies, but it is consistent with earlier studies showing that children exposed to farm animals during infancy are less likely to have allergies later in life.
[Allergy, online Nov. 18, 2010]