(NaturalNews) Humans and gastrointestinal parasites might have co-evolved in such a way that the parasites actually help regulate to human immune system to prevent against allergies, according to a study conducted by researchers from the University of Nottingham.
Researchers believe that over the course of millions of years, gastrointestinal parasites have evolved an ability to suppress the human immune system as a survival mechanism. Because parasitic infestation has been so common throughout human evolutionary history, the human immune system has in turn evolved to compensate for this effect.
This means that if the parasites are removed, the immune system may actually function too strongly, resulting in maladaptive immune responses such as asthma, eczema and other allergies.
To test this hypothesis, researchers used drugs to eliminate hookworm infection in a 1,500 children between the ages of six and 17 who were living in a rural village in central Vietnam. This region was selected for its very low rates of allergies and high parasitic infestation rate. Two-thirds of all children in the area are infested with hookworm or other gastrointestinal parasites.
The researchers found that once the children were no longer infected with parasites, their rates of dust mite allergies significantly increased. This supports the hypothesis that parasites help regulate immune responses.
"The next step is to understand exactly how and when gut parasites program the human immune system in a way that protects against allergies, and for such studies, follow-up from birth will be essential," said researcher Carsten Flohr.
Researchers hope that understanding the relationship between parasites and the human immune system could lead to a better overall understanding of allergies.
"The prospects of further studies in this area are very exciting, as we could see groundbreaking treatments for asthma and other allergies developed as a result," said Elaine Vickers of Asthma UK, which funded the study.