These three terms are often used interchangeably, after experiencing uncomfortable digestive symptoms from food; but there is a difference.
What is a food allergy?
A food allergy occurs when the immune system sees food proteins as harmful substances. The food protein triggering the response is called a food allergen. The response is mediated by IgE immunoglobulins. Millions of Americans have food allergies, and the prevalence continues to rise. The most common food allergy triggers in adults are shellfish, peanuts, tree nuts, fish, and eggs; while the most common food allergy triggers in children are milk, eggs, peanuts and tree nuts. Any food, however, can potentially trigger an allergic response. The most serious food allergies can result in anaphylaxis. Although relatively rare amongst people with food allergies, it is a life-threatening situation that requires immediate medical attention. A vast majority of food allergies happen with minutes to hours of ingesting the food allergy trigger. This is different from food sensitivities, in general, which can have delayed responses up to 72 hours post-ingestion.
What is a food sensitivity?
Food sensitivities are immune responses to food via immunoglobulin IgG. A common form of food sensitivity is non-celiac gluten sensitivity, a sensitivity to gluten (a protein found in wheat, rye and barley). In these individuals, the gliadin protein triggers an immune response causing inflammation along the lining of the small intestinal wall. The inflammation can cause symptoms in the digestive system but also in many other areas of the body, including the brain. For example, many people with food sensitivities have issues with reflux, cough, “brain fog”, depression, anxiety, rashes, and more. Sensitivity reactions can be significantly delayed after eating the food sensitivity trigger, making it difficult to identify many times. Food sensitivities can often arise over time after consuming the same foods, and can be anything, even "healthy" foods.
What is a food intolerance?
Food intolerance reactions occur if someone’s digestive system lacks the proper enzyme(s) to digest a certain food. The most common example of this is lactose intolerance. Individuals with this type of adverse food reaction will generally have obvious digestive issues upon ingestion. Of importance to note, food intolerances are not immune reactions; however, because they happen in the digestive tract where a large portion of your immune system lives, they can cause secondary immune problems.
Figuring out your food issues: Though food reactions are common, they can be challenging to understand. Identifying the cause can be difficult and time-consuming, but it is worth the time and effort. There are a variety of ways to assess and evaluate for your individualized food trigger(s). Remember, there are two major types of immune-mediated food reactions (IgE allergies and IgG sensitivities) and the third type being from a lack of an enzyme.
1) The gold standard for determining if you have an adverse food reaction is to do an elimination/provocation test. This generally means you must remove 100% of the food(s) from your diet and then reintroduce them 1 at a time to see which one(s) you react to and with what kind of symptom(s). Because IgG-mediated food sensitivities can take days to show up and their effects can last 1-2 weeks, it is generally recommended to eliminate food(s) for a minimum of 21 days. This is so you can be more confident that you are feeling better from the elimination phase. Talk to your provider to see if an elimination/provocation test is a safe and effective choice for you. Certain individuals (e.g. children, pregnant or frail patients) may not be good candidates for this, especially if they would be prone to undereating.
2) A wide array of laboratory testing is also available to narrow down your list of potential food triggers. Your provider can recommend labs if appropriate for you. We have a food sensitivity panel available looking at 192 food and food products. Remember, the gold standard still includes performing an elimination/provocation test afterwards before labeling it as a true adverse food reaction.
The good news:
It is possible to reduce IgG food sensitivities through rebalancing the microbiome and improving intestinal permeability. However, not all food sensitivities may improve. It’s important to retest foods following an elimination period in order to determine if a patient is still reacting to a specific food. Food intolerance response can be minimized by supporting digestion and adding in a comprehensive digestive enzyme.