Dry Roasting Peanuts More Likely to Cause Allergies Than Raw Ones, Study

First Posted: Sep 22, 2014 09:48 AM EDT

Dry roasting peanuts are more likely to trigger allergy as compared to raw peanuts, a new study reveals.

Peanut allergy is one of the most common food allergies, especially in children. It is known to cause a number of symptoms that range from minor irritation to a life-threatening reaction called anaphylaxis. Peanut allergy occurs as a result of the body's overreaction to certain proteins present in peanuts.

In a new finding, researchers at the Oxford University found that while dry roasting the peanuts, the high temperature triggers certain chemical changes that is recognized by the human immune system, 'priming' the body to cause an allergic immune response on the next intake of peanuts. According to the researchers, this finding helps explain the variation in the number of people with peanut allergies in the Western World as compared to those in the East Asia.

The rate of people with peanut allergy is high in the West as dry and roasted peanuts are common there, whereas in the East people consume more of raw peanuts.

Lead researcher Professor Quentin Sattentau says: "We know that children in families with other allergies are more likely to develop peanut allergy. However our 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. We think we have identified the chemical modifications involved in triggering an allergic response to peanuts, and are currently exploring methods that are food industry-friendly to eliminate these groups."

In this study, the researchers purified the proteins from both roasted and raw peanuts, these proteins were then introduced in mice in three various ways: injecting the protein under the skin, applying it to the broken skin and introducing it directly into the stomach. They then measured the response of the mice's immune system to peanut extract.

The researchers noticed that the mice that were initially exposed to dry roasted peanuts had generated higher immune response to the peanuts as compared to the mice that were exposed to raw peanut proteins. The types of immune responses noticed were characteristics of allergic reactions.

First author Dr Amin Moghaddam of Oxford University says: "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. 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 finding is documented in the Journal of Allergy and Clinical Immunology.

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