Is it a Food Allergy, Intolerance, or Sensitivity?

gut health and digestive issues

Food allergy, food intolerance, and food sensitivity are often used interchangeably, but there are differences in symptoms, diagnosis methods and impacts on health. By understanding the differences between these reactions to foods, you can make food choices that optimize your health.

Food Allergy

What it is: An “over-reaction” of the immune system to a food or part of a food.

Symptoms: Range from mild to severe, most occur within two hours of eating and often start within minutes of eating the food. Symptoms can impact the skin, gastrointestinal tract, cardiovascular system or respiratory tract. Some symptoms include, but are not limited to hives, redness of the skin, itchy tongue or ear canal, nausea or vomiting, diarrhea, stomach pain, nasal congestion or runny nose, sneezing, an odd taste in the mouth, swelling of the lips, tongue, or throat that impacts swallowing or breathing, wheezing or shortness of breath, turning blue, a drop in blood pressure, loss of consciousness, chest pain, or a weak pulse.

Common trigger foods: While any food may trigger an allergic reaction, the most common are eggs, milk, peanuts, tree nuts, fish shellfish, wheat and soy according to the American College of Allergy, Asthma and Immunology. Diagnosis: Allergies are most commonly diagnosed by a medical provider with a skin-prick test. In this test, small amounts of allergens are placed on the skin and the skin is lightly pricked/scratched to activate the immune response. Results are generally available in about 20 minutes. Blood tests can also be used, but results take longer than the skin-prick test and are less exact.

Treatment: Complete avoidance of trigger foods is currently the only way to prevent allergic reactions.


Food Intolerance

What it is: A reaction of the digestive system when one has difficulty digesting a food.

Symptoms: Present in the stomach and gastrointestinal tract and may include gas, bloating, cramps, and stomach pain or diarrhea. Food intolerances are more often related to the amount of foods eaten and symptoms begin as the food is digested. A small amount of a trigger food may not cause a reaction, where a larger amount of the same food might.

Common trigger foods: While any food or ingredient could potential cause an intolerance, common sources include dairy foods (lactose), fruit and highly sweetened foods (sucrose and fructose), wheat/barley/rye (gluten), and food additives such as colorings and artificial sweeteners.

Diagnosis: Intolerances are diagnosed from trial and error or an elimination diet. An elimination diet removes common trigger foods and any other foods suspected of causing symptoms from the diet for two or three weeks. The foods are then reintroduced one at a time to monitor for symptoms. Keeping a food log and noting when symptoms appear is commonly used to connect foods eaten with symptoms.

Treatment: Avoiding the foods that cause symptoms is the only treatment. Some people may be able to tolerate small amounts without symptoms.


Food Sensitivity

What it is: Reaction to food or a food component that causes inflammation in the body.

Symptoms: Develop over a longer period of time compared to allergies or intolerances, they may include heartburn, fatigue, brain fog, acne breakouts and joint pain. It is possible to be sensitive to food eaten on a regular basis and not recognize they symptoms are related to specific foods eaten.

Common trigger foods: Wheat/barley/rye (gluten), dairy and sugar.

Diagnosis: An elimination diet or trial and error by tracking food and paying attention to symptoms is the only way to diagnosis food sensitivities. While there are IgG tests marketed to diagnose food sensitivities, they do not have scientific evidence to support the claim of being able to diagnose food sensitivities or intolerances.

Treatment: Avoiding the foods that cause sensitivity is the only treatment. Some people may be able to tolerate small amounts without symptoms. If you think you might have a food allergy, intolerance or sensitivity consult a healthcare provider for evaluation and diagnosis. Receiving a diagnosis before eliminating foods from your diet is an important step in protecting your health.


The providers at the Bastyr Center for Natural Health or Bastyr University Clinic can help you determine which food or foods may be problematic for you. Schedule an appointment with a Bastyr Center for Natural Health or Bastyr University Clinic today.

Sheila A. Berry is a dietetic intern at Bastyr University (2019) in Kenmore, WA. She believes in the power of whole foods to provide the nourishment and energy to help live our best lives.



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