IgG food intolerance testing

Sometimes certain foods may trigger some symptoms, such as headaches, digestive issues, joint pain or skin problems. It is extremely complex to figure out which foods are the culprits, as reactions are often delayed by a few hours or longer and given the complexity of food composition. To help identify potentially problematic foods, some health practitioners offer food sensitivity tests to detect Immunoglobulin G (IgG) antibodies.

While screening tests for IgG antigens are commercially available, the reliability of these tests is questionable, because positive IgG antibodies in the serum do not always correlate with clinical symptoms. Indeed, a positive IgG antibody result is thought to indicate a physiological response of the immune system after exposure to food components, rather than an imminent food allergy or intolerance. Unfortunately there is also a lack of evidence to support the efficacy of IgG food intolerance testing.

The gold standard for identifying food sensitivities is an elimination diet followed by an “oral challenge” of eating the eliminated foods one by one after a period of avoidance to determine your reaction — ideally without you knowing what’s being tested to avoid the placebo or nocebo effect.

If you don’t follow an elimination diet before the oral challenge for food sensitivities, your symptoms in response to consuming a food antigen may be masked or hard to detect.