New research suggests dry-roasted peanuts are more likely to trigger allergies than raw ones.
Chemical changes caused by the roasting process and the high temperature that come along with it could be recognized by the body's immune system, triggering it to set off an immune response the next time it is presented with peanuts, the University of Oxford reported.
The findings could help explain why there are so many more people in the Western world with peanut allergies compared with populations in East Asia. In the West people tend to roast peanuts, but in the East peanuts are usually eaten "raw, boiled or fried."
To make their findings researchers purified proteins from both dry-roasted peanuts and from raw peanuts. They introduced these proteins to mice by injection, through broken skin, and directly into the stomach. The team later measured the subjects' immune responses.
The team found the mice that had been exposed to dry-roasted peanuts had an increased immune response to all peanuts compared with those that had been exposed to raw peanut proteins.
"This is the first time, to our knowledge, that a potential trigger for peanut allergy has been directly shown," said Professor Quentin Sattentau, who led the research at the Dunn School of Pathology at the University of Oxford.
Past studies have revealed that roasting peanuts modifies their proteins, causing the immune system to have an altered response; this is the first time roasting peanuts has been linked to allergic triggers.
"Our results in mice suggest that dry-roasted peanuts may be more likely to lead to peanut allergy than raw peanuts: the dry roasting causes a chemical modification of peanut proteins that appears to activate the immune system against future exposure to peanuts," the study's first author Dr. Amin Moghaddam of Oxford University said. "Allergies in people are driven by multiple factors including family genetic background and exposure to environmental triggers. In the case of peanut allergy, we think we may have discovered an environmental trigger in the way that peanuts are processed by high-temperature roasting."
The findings were published in a recent edition of the Journal of Allergy and Clinical Immunology and were funded by the National Institute for Health Research (NIHR) Oxford Biomedical Research Centre, the US National Institutes of Health and the Swiss National Science Foundation.
