Many who think they have food allergies actually do not.
A new report, commissioned by the federal government, finds the field is rife with poorly done studies, misdiagnoses and tests that can give misleading results.
While there is no doubt that people can be allergic to certain foods, with reproducible responses ranging from a rash to a severe life-threatening reaction, the true incidence of food allergies is only about 8 percent for children and less than 5 percent for adults.
Yet about 30 percent of the population believe they have food allergies. And, Dr. Riedl said, about half the patients coming to his clinic because they had been told they had a food allergy did not really have one.
Even people who had food allergies as children may not have them as adults. People often shed allergies, though no one knows why. And sometimes people develop food allergies as adults, again for unknown reasons.