People in East Asia eat just as many peanuts as people in North America and Europe but have much lower rates of peanut allergy; researchers believe they now know why. Scientists injected mice with proteins from peanuts that had been dry-roasted and from raw peanuts and found that the roasted peanut protein caused a much stronger immune system reaction, reports the Los Angeles Times. In East Asia, peanuts tend to be boiled, fried, or eaten raw instead of roasted, and while food allergies in general occur there at the same rate as in the West, peanuts are a "striking exception" that the difference in cooking methods could explain, the researchers write in their study, published in the Journal of Allergy and Clinical Immunology.
The researchers say the immune system response appears to have been the result of chemical changes in the nuts caused by the high temperatures of the roasting process, reports the BBC. "This is the first time, to our knowledge, that a potential trigger for peanut allergy has been directly shown," the lead researcher says. He adds, however, that the "research is at an early stage and we think that it would be premature to avoid roasted peanuts and their products until further work has been carried out to confirm this result." (Click to read about more unusual allergies: to sunlight, and newspaper.)