Believe it or not the father of medicine Hippocrates, the one who is quoted as saying “let food by thy medicine” was also the first known person to record an adverse and likely allergic response to food, cheese to be precise. I would have loved to know Hippocrates thoughts as he observed these foods that he considered to be medicinal to the body causing such negative reactions. We now have so much more knowledge and understanding of the body’s immune system, but even still it can be difficult for us to wrap our minds around the concept that a seemingly healthy food might be causing internal chaos and inflammation. Now when we talk about foods having a negative impact on health we categorize them as either a Food Allergy, Food Intolerance or a Food Sensitivity. Many people confuse these three conditions and use them interchangeably when in fact they are very different. Over the next three posts, I’m going to go into more depth about how each one occurs, how we can tell the difference and what our options are.
The Nuts and Bolts-what IS a Food Allergy?
Let’s start with food allergies. Ask almost anyone if they know what a food allergy is, and they will probably give you a resounding YES! Ask them how does one develop a food allergy or how is a food allergy diagnosed and the answer might not be so easy to come by. Food allergies are immunoglobulin E or IgE based reactions and can be the most serious food based reaction that can occur. Food allergies result in symptoms ranging from a mild rash or hives to life-threatening anaphylaxis shock.
Here’s what how a food allergy develops, you are introduced to food, let’s say peanuts. The first time you eat the peanut your immune system looks at it, thinks is looks suspicious but gives it a free pass. However, the immune system gets busy creating specific peanut fighting soldiers aka IgE antibodies so that next time that sneaky looking peanut returns the body is prepared for war. The next time you eat encounter peanuts (in any form), the immune system calls the IgE soldiers in and sets off to attack and kill the peanut proteins with full force. The first time you experience an allergic reaction, the symptoms may be a very mild rash or hives and with continued exposure increase in severity to anaphylaxis shock. It’s very very important to note here that the first time you experience an allergic reaction, you could jump straight to an anaphylaxis reaction. It’s also not uncommon to suddenly experience a reaction to food that you’ve eaten and enjoyed for years; there are also less common food allergy subcategories such as FPIES and Oral Allergy Syndrome that are often overlooked and misdiagnosed.
Any food can result in an allergic reaction there are eight main offenders that make up about 90% of all food allergy reactions:
- Tree Nuts
- Peanuts (actually a legume not a nut)
How Do I know? Getting a diagnosis
Approximately 4-6% of the population suffer from allergies with reactions occurring within 2 hours of consumption, but on rare occasions, the response may occur four to six hours post meal. There may be instances where you experience an immediate reaction i.e. eat a peanut=can’t breath= food allergy. In other occasions, it may be harder to determine the culprit, so what do you do? If you suspect that you have a food allergy, make an appointment with your allergist. Most likely your doctor will do one of the following tests:
- The Rast Test: Rast stands for radioallergosorbent test and is a blood test designed to identify allergen-specific IgE antigens.
- Skin Prick Test: In the skin prick test drops of solution are dropped on your back or arms a small needle is used to prick the skin to allow the solution to be absorbed through the skin. Within 30 minutes the Dr. will review the area for wheals or what might be considered a small whelp, these are measured and used to determine if you have an allergy. While very effective for non-food related allergies. Skin prick tests for food related allergies are notorious for false positives and are usually only accurate about 50% of the time.
Unfortunately, both the RAST test and skin prick test are of questionable accuracy. A retrospective study of 125 children in 2010 identified that 84%-93% of foods that had been identified as an allergen from a RAST or skin prick test actually did not elicit an allergic reaction when reintroduced into the diet. Which leads us to the ultimate method of determining a food allergy-
- The Elimination Diet: The gold standard in determining food allergies, the best way identify a food allergy is an elimination diet. Start by removing the suspected foods for about six months. After six months, you can start adding the suspected foods in one at a time, waiting about three days between each new food, watching for signs of an allergic reaction. If you plan on doing an elimination diet to test for food allergies, please discuss your plan with your doctor so that you can plan a safe way to introduce potentially allergenic foods back into your diet.
Have a question about food allergies that I didn’t answer? Come on over to my Facebook group and let me know.