Food Allergies

at 4:23 AM

A new report  published this week in the American Journal of Medical Association finds that the field of food allergies is rife with poorly done studies and misdiagnoses and tests with misleading results.  According to an author of the report, Dr. Marc Riedl from the University of California in Los Angeles the true incidence of food allergies in adults is 5% and in children it is 8%.  Although about 30% of the population believe they have food allergies.  Often children who have food allergies shed them as they grow up to be adults.  For their report Dr. Riedl and his colleagues looked at all the papers published on food allergies between January 1988 to September 2009 (about 12000 articles).  The lead author of the study, Dr. Jennifer Schneider Chafen said that usually the subjects are injected with a tiny amount of the suspect food and the presence of IgE (an antibody associated with allergies) is looked for in the blood.  Using these tests, there is less than 50% chance that the subject has a true food allergy. 

A better test is to give the 'food challenge' where the subjects are given a small amount of the suspect food (or placebo) to eat.  If the disguised food causes a reaction then the person has an allergy.  Authors of the new report say even accepted dogma like breast-fed babies have fewer allergies and that babies under the age of one should not be given foods like eggs, have little research to back them up.

Dr. Boyce from Harvard medical school says  that simply because an individual has a positive IgE reaction to a certain food does not mean they are necessarily allergic to that food.  He also says that there are plenty of people with IgE antibodies to different foods who do not have a reaction to them.

So basically it seems that the allergy guidelines may change in the future so that skin-prick tests or presence of IgE antibodies won't be the sole reason for dictating whether a person is allergic to a specific type of food.