How to Check for Food Intolerances
With true food allergies, with sudden onset of face and lip swelling, general “itchiness,” and skin rash, it’s generally easy to identify the offending food because the reaction occurs so quickly. Because the symptoms of food sensitivities may occur one or two days after eating the offending food, these are much harder to diagnose.
Screening blood tests, which check for up to 100 commonly eaten foods, can be helpful, but the most valuable diagnostic tool is a food sensitivity elimination diet. Your doctor can order food sensitivity blood tests, as well as tests to check for lactose intolerance and gluten sensitivity.
Whether you opt for blood tests, skin tests, or elimination diets, you can begin to identify the culprits in your diet causing you grief. Very few skin tests work for food sensitivities, but you may find that a combination of dietary changes and diagnostic tests give you the answers you’re craving.
There are several different methods of trying an elimination diet to identify problematic foods. Regardless of what you try, keep an accurate food journal for the time period you are testing. Do not try to rely on your memory to track what you ate when, and what symptoms you had for how long.
The easiest elimination diet involves you completely eliminating all dairy, egg, corn, wheat, citrus, and soy products for at least one week. Since these are by far the most common offenders, if, after one week of complete elimination, you feel exactly the same, with absolutely no improvement of your symptoms, then food intolerances are probably not present.
However, if you feel “better,” you may be on to something. Now it’s time to play detective. Add one food group back into your diet every three days and record your physical response. If nothing occurs, remain on that food, and add the next on the list. Ultimately, you’ll likely unearth the guilty party. If you feel better eliminating wheat, be sure to have your doctor test you for gluten sensitivity (celiac disease).
The majority of problematic food sensitivities are the delayed-onset type (IgG), taking hours to days to occur. Immediate reactions are easier to identify and eliminate because they have a fast onset (IgE antibody). (Skin prick testing identifies only IgE type, and is better for environmental sensitivities.) The blood testing screens multiple foods for reactions based on both immediate and delayed onset (IgG and IgE antibody reactions).