What’s the difference between a food allergy, a food sensitivity and a food intolerance?
I often hear people using these terms interchangeably but they describe different responses that the body has to food. The symptoms can be the same which can make it hard to tell which one you might have. But treatment varies, so knowing which one you have is important.
The symptoms of food allergies, intolerances and sensitivities overlap quite a bit. In addition, those symptoms can be vague and located anywhere in the body which makes it particularly difficult to diagnose. The most common symptoms are centered around the digestive tract: nausea, vomiting, diarrhea, constipation, heartburn, or gas. I’ve also seen skin reactions like acne or eczema, headaches, increased PMS cramping, and fatigue. The list of symptoms of food sensitivities could go on and on.
The term allergy describes a specific type of immune response. People can be allergic to pets, pollens, grasses, foods, etc. The most common foods that trigger a true allergic reaction are peanuts and shellfish. The allergic response can be serious and even life threatening. That’s why people with allergies might carry an epi-pen and why many elementary schools are completely peanut-free. For a child with a peanut allergy even touching a table where a peanut butter sandwich had been lying could be enough to trigger a serious response.
Allergies trigger a type 1 immune hypersensitivity response. This involves T cells, B cells and mast cells. The first time someone is exposed to an offending food (an allergen or antigen) their body creates antibodies or immunoglobulins, specifically immunoglobulin E, IgE. These IgE antibodies then locate themselves on mast cells. After that every time someone is exposed to that particular allergen the IgE antibodies trigger the mast cell to release histamine. The histamine causes local blood vessels to dilate which causes symptoms like runny nose, runny eyes, throat swelling, etc. This reaction is immediate, happening with just a few minutes. Blood and skin prick tests are good ways to diagnose an allergy.
A food intolerance is not an immune response at all. Instead it’s when the body is unable to properly digest a food, usually because it is missing an enzyme. For example people who are intolerant to dairy do not have lactase, the enzyme that breaks down the lactose protein found in milk. Individuals could be intolerant to sulfites, fructose, or other food additives.
A food sensitivity is sometimes called a non-IgE reaction. That’s because it involves the immune system, but not the IgE antibodies. Immunologically it is usually a type 4 hypersensitivity reaction involving T cells, macrophages, cytokines and other inflammation mediators. What’s important to know is that while an offending food (an antigen) will start the response, the cells that are triggered are not specific to that food. This immune response is sometimes called a delayed reaction, and in fact the symptoms can appear 72 hours later. This makes it particularly difficult to pinpoint which food might be causing the symptoms. Nine out of ten people with a food sensitivity will be sensitive to dairy, eggs, soy, gluten, or corn.
The best way to identify a food intolerance or sensitivity is to avoid the probable foods for a period of time and then eat them again and note any symptoms. The symptoms might not appear until 2-3 days after the food is eaten. In my practice I recommend an elimination/reintroduction diet to help people identify food intolerances and sensitivities.
For a true food allergy, one should avoid the food they are allergic to forever.
For a food intolerance, in general it’s best to avoid those foods. It can be okay to eat a little bit occasionally, as long as you take appropriate digestive enzymes at the same time to help your body digest the food. I prefer 100% plant-based enzymes.
Identifying a food sensitivity is just the first step in a longer process of gut repair. Since a sensitivity is often caused by some sort of “leaky gut” that allowed the food proteins to come into contact with the immune system too soon, we want to strengthen the gut. The gut repair process can take months to years. My gut repair protocol uses 4 R’s. Remove the offending food completely from your diet. Restore proper function (this is individual and would address specific symptoms like constipation, heartburn or acne). Repopulate the gut with good bacteria. And last but most importantly, repair the lining of the small intestine.
If you have more questions about food allergies, intolerances and sensitivities, you can contact me, or schedule a free fifteen minute chat which can be in person in my Philadelphia office or via phone/Skype. I look forward to helping you illuminate your own health.