Science - March 18, 2004

New methods give certainty about food allergies

“Not everyone who thinks they have allergies actually has them,” says Amber Rontelap, PhD student at the Marketing and Consumer Behaviour Group. “They could also be reacting negatively to a foodstuff. They got sick once, for example, after eating peanuts and have since then always felt ill when they taste peanuts. But that is not an allergy.” Ronteltap developed a method that objectively indicates whether or not someone is allergic.

Ronteltap’s article will appear next month, although it’s taken a long time. When she sent the article to Allergy it was 2002 and she was studying in the sub-department of Human Nutrition. “Of course I am pleased that it is being published, but it is a shame that it has taken so long,” she says. “There is a lot of work to be done on food allergies. More and more people are suffering from them.”

If allergists want to know whether patients actually have allergies, they mix the allergenic products with foodstuffs and give them to the presumed allergy patients. “It has never been researched whether the patients could detect in one way or another the presence of the allergenic substances,” says Ronteltap. “That’s why we did it.” Ronteltap mixed various amounts of peanut flour with mashed potatoes and hazelnut flour with oatmeal and gave these foodstuffs to a panel of non-allergic consumers. The panel did not notice the presence of peanuts, but they did notice the hazelnuts.

“The problem was not the taste of the hazelnuts,” says Ronteltap. “It was the skins that had covered the hazelnuts that revealed the presence of the hazelnuts to the panel.” You can remove these by heating the nuts first, but then the nuts also lose their allergenic effect. Ronteltap developed her method in cooperation with the Utrecht hospital UMC, where allergists are now already using the method.

Willem Koert