How much is too much when it comes to allergens?

Buying food can be a minefield for people with severe food allergies. While allergenic ingredients must be listed on food labels, regulating labelling when it comes to trace amounts of allergens is tricky.

Precautionary labels such as ‘May contain traces of peanuts’ aren’t always used consistently and are sometimes used just to cover processors against legal action. These labels can induce allergy sufferers to take risks, as different people can tolerate more of a particular allergen than others.

Researchers from the University of Manchester have identified the level of five of the most common food allergens that would cause a reaction in the 10% of people who are sensitive to them.

“What we wanted was to find a level of allergen which would only produce a reaction in the most sensitive 10% of people. This sort of data can then be used to apply a consistent level of warning to food products,” said Professor Clare Mills, who led the study.

“What we’d like to see are warnings which tell people with allergies to avoid certain products completely or just apply to those who are most sensitive.”

The researchers analysed data collected from 436 people with allergies to peanut, hazelnut, celery, fish or shrimp. They were given small doses of the food they are allergic to and their reactions monitored.

Between 1.6 and 1.1 milligrams of hazelnut, peanut and celery protein produced a reaction in the most sensitive 10% of those studied. For fish it was higher (27.3 mg), and for shrimp, a significantly higher 2.5 grams of cooked protein produced a reaction. The researchers didn’t study raw shrimp and say they can’t rule out the possibility that it may have a different effect.

“This single study is part of the background to rolling out new warning guidelines across Europe, and alongside other work being carried out in Manchester and elsewhere we’re developing a strong evidence base to give consumers and industry confidence,” said Professor Mills.

The research paper ‘How much is too much?: Threshold dose distributions for five food allergens’ was published on 12 January 2015 in the Journal of Allergy, Asthma and Clinical Immunology.