The Difference Between Food Allergies, Intolerances, and Sensitivities

Granola with pears in a dark ceramic bowl with herbs and honey on a plate underneath it

Current data suggests that nearly 10% of people experience food allergy symptoms, which has been trending upward in the last 2-3 decades. Like many chronic conditions, the expression of food allergies can be influenced by genetics, environment, and the genome-environment interactions, or epigenetic effects [1]. Additionally, food-related symptoms may not be exclusively allergies, but they can also be defined by intolerances or sensitivities which typically elicit more mild symptoms and are non-immune reactions.

Food Allergies

Food allergies are immune reactions to food. This type of reaction occurs in response to an exposure of a food protein that the body identifies as harmful and subsequently creates antibodies (immunoglobulin E, IgE) to. A true food allergy can begin to cause symptoms immediately following ingestion.

Common allergy symptoms include rash, swollen or itching tongue, runny nose, hives, abdominal pain, vomiting, difficulty breathing, coughing, wheezing, or a closed airway. It’s important to remember that these reactions can range from mild to severe. Although many other foods can precipitate symptoms as well, the top offending foods are peanuts, tree nuts, wheat, soy, milk, fish, and shellfish [1]. In severe cases, anaphylaxis may impair breathing, resulting in a change of heart rate, or cause a drop in blood pressure – all of which can be life-threatening.

Food Intolerances

Food intolerances are non-immune reactions to certain foods or food components. These reactions often relate to a lack of digestive enzymes or other nutrients necessary to break down these food components. Examples of common intolerances include dairy, sulfites, histamines, lectins, preservatives, artificial colors, fillers, artificial flavoring, artificial sweeteners (saccharin, acesulfame, aspartame, neotame, and sucralose/Splenda), gums, (acacia gum, gum arabic, xanthan gum, etc), chocolate, citrus fruits, and acidic foods.

Symptoms of food intolerance may include flushing, cold or flu-like symptoms, inflammation, or an upset stomach. This occurs primarily because the stomach is unable to break down and process foods that are considered to be triggers. It’s thought that some symptoms are dose-dependent, meaning that a small portion of some foods may be tolerated without symptoms but a larger portion may not be.

Diagnosing food intolerances typically involves evaluating the individual’s history, completing laboratory studies, and then trying elimination diets or food challenges to help confirm a diagnosis [1]. The process of an elimination diet can be thought of as a period of trial-and-error. It consists of eliminating foods you suspect may be problematic until symptoms resolve, and then gradually reintroducing them over a period of time. During this time, you may also be asked to keep a food diary to record what you eat and the response your body has (if any) which can help pinpoint which foods you may need to avoid.

Food Sensitivities

Symptoms from food sensitivities are often delayed by hours or even days. Oftentimes, there are imbalances in the gastrointestinal tract that affect immunity. One of the most notable imbalances is intestinal permeability, otherwise referred to as “leaky gut syndrome.” Increased intestinal permeability can predispose individuals to increased inflammation, changes in immune responses, and nutrient availability [2].

Symptoms of food sensitivities can include migraines, fatigue, dizziness, worsened sleep, mood swings, depression, anxiety, unintentional changes in weight, dark under-eye circles, asthma, irritable bowels, bloating, wheezing, runny nose, ear infections, food cravings, muscle or joint pain, nausea, sweating, rashes, hypersensitivity, or acne. Common sources of food sensitivity include dairy milk, eggs, gluten (from wheat, rye, spelt, or barley), soy, shellfish, or tree nuts.

If you’d like more support with any dietary modifications or if you have additional questions, you can schedule an appointment.

1. Food allergy: A review and update on epidemiology, pathogenesis, diagnosis, prevention, and management
2. Changes in intestinal microbiota composition and metabolism coincide with increased intestinal permeability in young adults under prolonged physiological stress
3. Food Allergies: What You Need to Know
4. Immunoglobulin G testing in the diagnosis of food allergy and intolerance
5. Cow’s milk protein allergy