I talked briefly before about the lack of testing for food intolerance so now let’s delve more deeply into this issue. More specifically, let’s take a look at the difference between the common IgE-mediated reactions that have long been recognized as “food allergy” and the non-IgE-mediated responses, where the mystery lies.
IgE-mediated reactions will typically be swift and are potentially life-threatening; this type is why your child can no longer bring peanut butter sandwiches to school. Think swelling mouth and lips, projectile vomiting, breathing problems, and anaphylaxis. When the offending food enters the body, there is a nearly immediate immune response that causes symptoms very quickly. Researchers have now found there is a less common type of allergic reaction known as non-IgE-mediated food allergy (NFA) in which symptoms can take hours or even days to erupt. NFA is also an immune system response and commonly results in gastrointestinal responses, but can show up in other ways such as in the skin. The challenge with non-IgE-mediated food allergy is that it is not yet understood and there is no test available for it as there is for IgE-mediated. The only diagnostic tool available is elimination and challenge; taking the suspected food out of the diet to see if symptoms disappear, then adding it back in and watching for a reaction. Hence, it is believed that there is an under-diagnosis and non-validation of the degree of seriousness of this type of food allergy. In some cases, these symptoms are thought of as “food intolerance” because the offending foods come up as non-reactive in the IgE-mediated skin tests. They key to discerning the difference between NFA and food intolerance is in the type of response. Non-IgE-mediated responses are related to the immune system and have somewhat similar reactions as IgE-mediated, while food intolerance responses do not involve the immune system and thus have different symptoms. For me, this information is validating and encouraging as for years doctors and allergists have told me I should eat the foods that make my eyes and face swell, cause a rash, and make my asthma flare because my skin test said I wasn’t allergic to them. I have been insisting my issues were much bigger than an upset stomach or a little bit of itching, but usually get a pat on the head and sent on my way. With the more recent understanding of non-IgE, I finally have the confirmation I needed that there’s more to this story, and it’s not all in my head. To learn more, check out these sites. http://apfed.org/drupal/drupal/sites/default/files/files/IgE%20vs%20nonIgE%20reactions.pdf http://www.ncbi.nlm.nih.gov/pubmed/18782024 http://www.rch.org.au/uploadedFiles/Main/Content/allergy/Non%20IgE%20Food%20Allergy.pdf
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When I went to college right out of high school and was considering a career in dietetics, I was hesitant for a reason I could not unearth. As I grew older and found myself migrating back to the field of nutrition, that gut feeling I followed years ago became clear; my passion lies in wellness and prevention rather than caring for the ill. Older and wiser now, I understand there is room for both in a dietetics career but that I can still choose to focus on prevention in my work.
It’s therefore logical that I have often wondered what caused my food allergies, and if there is any way they could have been prevented. More importantly, I want to understand where is the current research is landing on this issue so I may help my future clients. Just as much of the information in the nutrition world, current guidelines have changed from the recommendations of the not so distant past. It used to be that doctors, dietitians and specialists told patients to avoid potential allergens during pregnancy and to delay introduction of them into the infant’s diet for one, two, even three years. Recently studies have provided evidence that this is not only a flawed approach, it very well may have increased the incidence of food allergy in the US. Countries who have continued to introduce common allergens from the time solid foods are started have held steady their rates of food allergy while the US, using the approach of withholding the common allergens, has seen an increase. It’s a sad truth that many people were significantly impacted by this wrong turn in science and have developed food allergies as a result of the advice their parents received. The silver lining is that we’re inching closer and closer to unlocking the mystery, and now we’re that much closer. http://www.todaysdietitian.com/newarchives/030413p14.shtml http://www.enttoday.org/details/article/1025783/Closing_the_Knowledge_Gap_New_food_allergy_guidelines_provide_clarity_to_some_ot.html I consider myself a hardworking, dedicated student that puts her all into her work, perhaps even arguable spending too much time and effort on relatively small assignments. Never has that been more true than in the past week.
When I have a food reaction, it’s not pretty. While I may not be relegated to the nearest powder room with gastrointestinal woes like some, I usually wish to be. Do you remember the round, puffy, oddly shaped faces of the Who’s in Whoville? Cute on a cartoon character, but on me...not so much. Now add to that image face a fiery red, itchy rash that people recoil from for fear of
contamination with Who-cooties. My eyes and cheeks swell and my face and neck are rashy, a bit weepy and itching unbearably. Whenever I arrive at work with a freshly mottled face, my boss is boss is always quick to point out I must have eaten something again to which I promptly come up with the witty retort of…..yup. (My snarky inner-self is meanwhile saying to those who point it out “Thank you Captain Obvious”!) Now, I’m not a particularly vein woman, but having to cross paths with every patient that walks in our door with all of the awesomeness occurring on my face makes me feel about 2 inches tall and aching to hide at home. I watch the patients eyes as they sneak peeks and I want to melt right into the floor to avoid the judgment. Never mind that it is also physically tormenting me a la the chicken pox our parents screeched at us to stop scratching. It’s little consolation to me that others also experience their symptoms primarily or exclusively through their skin, but I’m grateful that our suffering inspires research. One related bit of investigation is on “pseudoallergens”, which are the substances in various foods that elicit allergy-like symptoms even when one is not necessarily diagnosed as allergic. The primary suspects are various food additives and naturally occurring substances. The common skin disorder urticaria and its ties to pseudoallergens is being studied to find out if a pseudoallergen-friendly diet alleviated symptoms and improved quality of life for patients. In this particular study the subjects followed a prescribed diet and kept a diary for 31 days and were then admitted to the hospital for testing. Quality of Life tools were also used throughout. The results showed that one third of the participants were helped by eating a pseudoallergen-friendly diet which is encouraging news. Granted, two thirds of the population was left still searching for their triggers, but the relief of those with successful outcomes was surely immensely welcomed. Hopefully those people were able to face the world again without feeling like a carnival freak show. http://onlinelibrary.wiley.com/doi/10.1111/j.1398-9995.2009.02130.x/full And a little further information for you: http://www.nature.com/jidsp/journal/v6/n2/full/5640039a.html So much is still to be learned and understood about food intolerance. While food allergy has proven testing methods, albeit with some false positives and negatives, food intolerance testing is elusive. This article from the Journal of Academy of Nutrition and Dietetics addresses that no solid test for intolerance exists and therefore many patients are left with self-diagnosis and even fear that is impacting their daily lives.
This is a hot-button topic for me as I am one of those patients who tested negative for numerous food allergies, yet I have the medical records and pictures of my reactions to support that when I eat a list of foods, my face swells and becomes covered in an itchy, burning rash, and I am a miserable mess of a person. I don’t much care what the allergy tests say when the elimination and challenge results are so stunningly clear. I often long for definitive tests to make my multiple intolerances much more definitive and less mysterious, but the bottom line is if I react to it, I don't eat it, and I don't need a test to provide that information. Still, the issue of mis-diagnosis and the resulting negative impact on quality of life for some will continue until researchers can unlock an accurate test for food intolerance that rivals the relatively reputable results of true allergy testing. While I can absolutely see the side of self-diagnosis being unnecessary and having psychological impact, I am firmly planted on the side of food intolerance being a very real experience and desperately hope researchers will continue their quest for clear testing methods. Where do you stand? Overly diagnosed and self-diagnosed, or understudied medical field that just doesn’t have clear answers yet? http://www.journals.elsevierhealth.com/periodicals/yjada/article/S0002-8223(09)01608-3/fulltext Understanding the difference in terminology is always a first step when exploring a subject. Here's a site to get you started.
http://www.todaysdietitian.com/newarchives/100111p52.shtml From the time I was very young I have suffered from unbearably itchy, burning eczema. My mom had to use cloth diapers on me at a time when it was not fashionable to do so because the chemicals and perfumes would cause a reaction.
Later doctors told me it was using scented laundry detergent, lotions and soaps that were the problem. I was handed one prescription after the next as my response to each diminished, but the eczema still raged leaving me with painful open fissures, particularly on my hands. |
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