Food Allergies vs Food Sensitivities
What is the difference between having an allergy or a sensitivity to a food? There can be lots of confusion here because the word ‘allergy’ is more commonly used, but often incorrectly. I will explain the important differences between a food allergy and a food sensitivity, as well as recommended tools, techniques, and testing to properly identify them!
Food Allergies
Most people tend to know if they have a true food allergy. This is because food allergies usually create an immediate immune response, often within minutes of eating and up to 2 hours later.
True food allergies are mediated by the Immunoglobulin E (IgE) response. An IgE antibody will attach to the food molecule and can also attach to Mast Cells. This leads to a series of inflammation in the body due to the release of histamine and production of cytokines.
Allergic reactions may include:
· Anaphylaxis (swelling, nausea, vomiting, difficulty breathing, or shock)
· Asthma
· Itching
· Hives
· Sinusitis
· Hay Fever
· Dermatitis
Food Sensitivities
Food sensitivities are much more difficult to identify because symptoms or reactions can be delayed between 2-72 hours after exposure to the food! This means, for example, that if you have a dairy sensitivity and you eat cheese on Monday you may not experience a reaction (such as a headache or fatigue) until Wednesday! Yet if you are consistently eating dairy, you may have daily headaches/fatigue and have no idea what’s causing it.
Food sensitivities include different immunoglobulin responses such as IgA, IgG, IgM, and more.
1. IgA: specific to mucosal regions such as the GI tract. Long term exposure to a food stimulating the IgA response can lead to intestinal inflammation.
2. IgG: can impact the body systemically, and get stimulated by proteins in food that aren’t recognized by the immune system as ‘safe.’ Reactions are delayed and can vary across the whole body.
3. IgM: created during infections when the body is exposed to bacteria or viruses. The antibody activates complement C3d.
- C3d: part of the immune system called complement, and is responsible for amplifying the reactions of immunoglobulins. This means that the reaction to food sensitivities will be more severe if this antibody is also present.
Food sensitivity reactions may include:
· Headaches
· Brain Fog
· Joint/Muscle Pain
· Fatigue
· Diarrhea/Constipation
· Abdominal Cramping
· Mood Swings or other Behavioral Issues like ADD/ADHD
· Coughing
· Wheezing
· Itching
· Dark Circles Under the Eyes
· Skin Rashes
· Autoimmune Conditions
· And More…!
Identifying Food Allergies/Sensitivities
Food Logging can be an effective way to get in touch with your body and to start identifying patterns. Food allergies may be easier to identify this way, while food sensitivities will prove to be more difficult due to the wide range of reactions and the delay in reactions.
Elimination Diet is a restrictive diet that eliminates foods that are common allergens and other suspected foods. After abstaining from these foods for a set amount of time, food items are added back in slowly, one at a time, in a systematic way in order to observe reactions or symptoms.
Lab Testing is a great option that offers quick insight to what your immune system is reacting to. There are many tests out there and they each have their strengths and limitations. For example, a Skin Prick Test completed by an Allergy Specialist will only show IgE (allergy) reactions. Serum Testing (performed by blood draw) can measure levels of many different immunoglobulins including IgE, IgG, IgG4, C3d, and more, yet false positives can occur due to cross reactions. A salivary collection (spit) is needed to identify IgA reactions in the digestive mucosa.
Click here to get more information on the Dunwoody Food Antigen Test that I order most often in my practice to help identify food allergies and food sensitivities.