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Food Allergy vs. Sensitivity: What’s the Difference?

What’s the Difference?

Gluten-free, dairy-free, nut-free…specialized diets are everywhere you look. But not everyone with special dietary needs has the same reaction to their offending foods. What’s the difference between being allergic to a food and being sensitive or intolerant to it?

The key difference between a food allergy and sensitivity is the body’s response. When you have an allergy, your immune system gets involved. If you have a sensitivity or intolerance, the reaction is largely triggered in the digestive system.

Food Sensitivities

Food sensitivities are not life threatening. There are also food intolerances, which are also not immune mediated, and are due to the inability to process or digest a food.
Sherry Farzan, MD, allergist and immunologist with North Shore-LIJ Health System in Great Neck, N.Y.

Food sensitivities and intolerances are far more common than food allergies, according to the British Allergy Foundation. Neither involves the immune system. Either a food triggers an intolerance in your digestive tract, where your body is unable to properly break it down, or the body reacts to a food you are sensitive to. For example, milk intolerance is where your body is unable to break down lactose, a sugar found in dairy products. Or if you are sensitive to histamines, you may get headaches after you eat foods that contain histamines.

You may be sensitive or intolerant to a food for a variety of reasons, including:

  • not having the right enzymes you need to digest a certain food
  • reactions to food additives like sulfites or artificial colors
  • psychological factors, like an extreme dislike of certain foods
  • pharmacological factors, like sensitivity to caffeine or other chemicals
  • sensitivity to the toxins naturally found in certain raw legumes like lima beans

The symptoms of intolerance are all digestive-related and can include: gas and bloating, diarrhea, constipation, cramping, or nausea. Symptoms of food sensitivity vary.

Food Allergies

The Difference in Symptoms
  • Symptoms of food intolerance include gas, bloating, diarrhea, constipation, cramping, and nausea.
  • Symptoms of food allergy include hives, swelling, itching, anaphylaxis, and dizziness.
  • Your immune system is your body’s defense against invaders — whether bacteria or the common cold virus. You have a food allergy when your immune system identifies a protein in what you eat as an invader. It reacts by producing antibodies to fight it.

    “A food allergy is an immune-mediated reaction to the food,” explains Farzan. “The most common type of food allergy is an Immunoglobulin E (IgE)-mediated reaction. IgEs are allergic antibodies which cause an immediate reaction due to release of chemicals, such as histamine, from mast cells.” 

    Unlike a food intolerance or sensitivity, food allergies can be fatal. In extreme cases, ingesting or even touching a small amount of the allergen can produce an intense reaction.

    Symptoms of food allergy include:

    • skin reactions, like hives, swelling, and itching
    • anaphylaxis, including difficulty breathing, wheezing, dizziness, and, ultimately, death
    • digestive symptoms

    What to Do in an Emergency

    The Big 8
    Eight foods account for 90 percent of allergic reactions: milk, eggs, fish, shellfish, peanuts, tree nuts, wheat, and soybeans.

    “Individuals who have food allergies must strictly avoid these foods, and be trained — or a child’s caretakers be trained — to treat accidental ingestions with anti-histamines and/or self-injectable epinephrine,” says Farzan. “Self-injectable epinephrine must be readily available — and the individual/caretaker should be knowledgeable regarding its correct use — to all food-allergic individuals at all times.”

    Because the potential effects of an allergic reaction are so severe, great strides are made to accommodate people with food allergies. School lunchrooms, for instance, may be peanut-free to cater to children with peanut allergies. Likewise, product labels are required to alert consumers when a food is made in the same facility that processes common allergens.

    Whether you have a food sensitivity or an allergy, it’s best to steer clear of those foods. While one may be more serious than the other, neither is pleasant.

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