Since I’m big fan of NPR, I was excited to see that their food blog, The Salt, covered a story about testing for food allergies. As I discussed in a recent post, food allergy testing can be a tricky task. Blood tests are often unreliable and are not always the most effective method for getting to the source of a patient’s symptoms. In fact, allergies aren’t always the problem, since intolerances and other digestive issues can produce similar reactions to food.
So what should you do if you suspect food allergies? According to my allergist, as well as the experts cited in this story, the best method is trial an error. Here’s what the NPR post had to say:
“A lot of people think they have food allergies, but they’re likely wrong.
That’s partly because it’s easy to confuse common food-related problems like lactose intolerance or celiac disease with an allergy. But it’s also because there are a lot of tests promoted for food allergies that don’t measure up.
That includes a blood test called IgG analysis, which is often promoted on the Internet as a way to identify problem foods. It sounds almost exactly like an IgE test, which is used by allergists to measures the immune system’s response. (A true allergy is when the immune system reacts to something that’s not a real threat.)
An article in the current Canadian Medical Association Journal reminds doctors that IgG tests aren’t reliable tests of food allergies.
It follows the guidelines on diagnosing food allergies from the National Institute of Allergy and Infectious Disease in 2010, which lumped IgG testing with more than a dozen “nonstandardized and unproven procedures” that should be avoided. A positive IgG test, the expert panel said, could cause people to avoid foods that they can safely eat.
That got us here at The Salt wondering what does work.
To find out, we called up Scott Sicherer, a professor of pediatrics at the Jaffe Food Allergy Institute at the Mount Sinai School of Medicine.
The NAIAD guidelines say that a “food challenge test” is the gold standard for food allergies, and Sicherer agrees. To do one, he feeds patients small amounts of a suspect food over the course of an hour, in his office (for safety reasons). “Ultimately the proof is in the pudding. If someone is able to eat a food and not get sick from it, they don’t have a problem with it,” he says.”