Food Sensitivity, Allergies and Intolerance

Understanding the differences between food sensitivities, food allergies, and food intolerance

The terms food sensitivity, food allergy, and food intolerance are often used interchangeably and incorrectly. There is an ongoing debate in scientific and medical circles on how to properly define and use these medical terms.

The general consensus is that food allergy can be defined as any adverse reaction to food that involves our immune system. This further breaks down into two kinds of reactions – food sensitivity and food allergy.

— Food sensitivity

Food sensitivity (also known as delayed food allergy) can manifest in many different ways. Delayed reactions can affect any organ system in the body and can take from 45 minutes to several days for symptoms to manifest. The delayed onset of symptoms and complex physiological mechanisms involved in food sensitivities make them an especially difficult problem to solve (either on your own or with laboratory serum tests).

In fact, food sensitivities often go undiagnosed or misdiagnosed. The treatments prescribed usually provide only temporary relief that mask the symptoms instead of addressing the root cause of the food sensitivity issue.

— Food allergy

A food allergy is a very specific immune system response involving either the immunoglobulin E (IgE) antibody or T-cells. Both are immune system cells that react to a particular food protein. (Source:

It is estimated that food allergy affects about 1-2% of Americans. While most allergic reactions are not life threatening, they produce uncomfortable symptoms of varying degrees.

The most common foods that trigger food allergies are peanuts and other types of nuts, shellfish, and foods that contain sulfites.

The most extreme allergic food reaction – anaphylactic shock – is a severe hyper-reaction of the immune system caused by a massive release of histamine and other chemical mediators.

— Food intolerance

Food intolerance can produce symptoms similar to food allergy, but does not involve the immune system. Instead, when the food is consumed, it is not properly digested and begins to ferment inside the gut.

The best example of food intolerance is lactose intolerance. Bloating, loose stools or diarrhea, and gas characterize this condition.

Food sensitivities vs food allergies

The differences between the two types of immune mediated adverse food reactions are summarized in the table below.

Food Sensitivities Food Allergies
Body Organs Involved Any organ system in the body can be affected Usually limited to airways, skin or gastrointestinal tract
Symptom Onset Occurs From 45 minutes to 72 hours after ingestion From seconds to one hour after ingestion
Are symptoms acute or chronic? Usually chronic, sometimes acute Usually acute, rarely chronic
Percentage of population affected 20-30 percent 1-2 percent
Immunologic Mechanisms White blood cells, antibodies: IgA, IgC (and subclasses), IgM, C3, C4 IgE
Non-immunologic Mechanisms Toxic, pharmacologic None
How much food is needed to trigger reaction From small amount to large amount, often dosage-dependent One molecule of allergic food needed to trigger reaction

Nutritional therapy to treat food sensitivity – Cape Cod MA

Food sensitivities are related to many common health problems. Neglecting or not managing food sensitivities is often the difference between treatment success or failure, and can mean the difference between complete remission or only modest outcomes.

Contact Amy Rose at 508-274-8222/ 774-413-5238 to discuss your food sensitivity issues and a plan to improve your health and wellness!


  • Amy Rose Sager is a Nutritionist, Registered Dietitian and Certified LEAP-MRT Therapist. She provides in-person or phone consultations with patients throughout Cape Cod, Plymouth and southeastern Massachusetts. Her specialties are managing food sensitivities; plant-based eating, cancer and eating for life. Patients come to her for help with IBS (irritable bowel disorder), Crohn's disease, plant-based diet eating and food allergies.
    • Cape Cod: Barnstable, Bourne, Brewster, Centerville, Chatham, Cotuit, Dennis, Falmouth, Forestdale, Harwich, Hyannis, Marstons Mills, Mashpee, Orleans, Osterville, Pocasset, Provincetown, Sagamore, Sandwich, Wellfleet, Yarmouth.

    • South Coast MA: Buzzards Bay, Fairhaven, Onset, Marion, Mattapoisett, Rochester, Wareham

    • South Shore MA: Abington, Bridgewater, Carver, Duxbury, East Bridgewater, Halifax, Hanson, Hanover, Kingston, Marshfield, Middleboro, Norwell, Pembroke, Plymouth, Plympton, Raynham, Rockland, Scituate, West Bridgewater, Whitman