DRY-roasted peanuts may be more likely to trigger allergic reactions than the raw variety, a study has shown.

The high temperature involved in dry-roasting causes chemical changes that can sensitise the immune system to peanut proteins, research suggests.

Scientists believe this may explain why peanut allergy is more common in the West than in eastern Asia.

Dry-roasted peanuts are popular in the West. In the East peanuts are more often used in cooking and eaten raw, boiled or fried.

The research involved comparing the effects of proteins from dry-roasted and raw peanuts in mice.

Animals initially exposed to dry-roasted peanut proteins subsequently developed a far stronger immune reaction to peanuts.

Dr Amin Moghaddam from Oxford University said: "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."

Professor Quentin Sattentau, who led the Oxford University research team, stressed the work was at an early stage and it was premature to avoid dry-roasted peanuts or their products.

He added: "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." The findings appear in the Journal of Allergy and Clinical Immunology.