Nutrition Tips - Reliability of food sensitivity tests

My name is Christine Marquette, and I'm a registered dietitian, and I'm going to talk to you about how reliable are food sensitivity tests. There are actually several different food sensitivity tests out on the market these days, and it really depends on the pathway that they're testing. For example, with your immune system, there are typically four recognized immune pathways. Type one is what's referred to as IgE, or Immunoglobulin E antibody-mediated response, and in that one, it's actually a true food allergy. When IgE antibodies are released in response to your particular food, you react almost immediately with things like hives, swelling, difficulty breathing. That's one pathway. The second pathway is also antibody-mediated, but rather than IgE, it could be a different antibody -- IgM, IgA, something like that. Type three is a delayed sensitivity reaction, so it's not immediate in the sense that allergy is. This one could take hours to days for it to show up, and it's a different pathway using different antibodies. This one uses IgG antibodies. The last pathway, type four, still immune-mediated, but it doesn't use antibodies. It doesn't use IgG, IgM -- none of that. It actually is T-cell mediated. So what that means is when you have a food that's ingested and your body reacts badly to it, it will release...your T-cells will cause it to release a lot of different mediators -- things like histamine, cytokines, leukotrienes -- things like that that cause inflammation. So it is still involving your immune system, but it isn't involving those IgG or E or A or M antibodies. So the food testing how reliable it is depends on what pathway that it's testing. Most of the food sensitivity tests that use IgG are not necessarily very reliable for food sensitivity because of the fact that IgG can either be protective or it can be pathogenic, meaning negative. And if that's the case, you don't really necessarily know if a high level of IgG is detected. Is it really bad or is it good? Your body could actually be protecting itself rather than actually having a bad reaction. So it's not very reliable in determining your sensitivity to a particular food. Other sensitivity tests that actually just measure mediated release or they measure how much histamine is in your blood, that one is going to be a lot more accurate because it's an end-point test. It's actually seeing what's happened, what's...you know, is there inflammation that's being caused? It can detect those types of things, so the end-point tests are much more accurate as far as sensitivity tests go.