Your neighbor is allergic to peanuts.  Your child’s friend is sensitive to wheat.  Your spouse is lactose intolerant.  What does it all mean?  The words “allergy,” “sensitivity,” and “intolerance” are often used when describing adverse reactions to food.  I should say, they are often misused.  Let me explain.

A food allergy means that there is an IgE immune antibody response to a food–typically a protein within a food–resulting in true allergic symptoms.  These symptoms occur within minutes to hours after ingesting the food.  Symptoms include rashes, hives, itchy eyes, runny noses, swelling and digestive upset related to the activation of certain immune cells known as mast cells.  Food allergy can also cause anaphylaxis, or anaphylactic shock: a very serious, rapidly progressing allergic reaction which can be fatal.  You may be most familiar with anaphylactic shock as what happens to people who are allergic to bee stings; persons with true food allergies may carry epinephrine injections (“epi pens”) to use in the event they unknowingly encounter their allergen.  Generally speaking, allergies worsen over time with increased incidence of exposure.  One can not have a true allergic reaction the very first time he is exposed to a food.  However, he may have an allergic reaction if it is his first known exposure, and he was unknowingly exposed in the past, e.g. by cross-contaminated ingredients.  It is rare but not unheard of for someone to have a life threatening reaction to a food without first having more minor symptoms at previous exposures.

Food intolerances and sensitivities are less well defined, but we use the terms to talk about different manifestations of non-allergic reactions.

Someone has a food intolerance when their body does not handle that food well.  For example, lactose intolerance results when a person is deficient in the lactase enzyme.  People with intolerances often experience discomfort hours to one day after ingesting the offending food, and symptoms are typically confined to the GI tract.  Food intolerances result in gas, bloating, diarrhea, constipation, indigestion, abdominal pain and more.  These symptoms are often caused by an inability to appropriately digest a given food.  Symptoms generally resolve after a very short (hours to a day) avoidance, but can quickly return with repeat exposure.

Food sensitivity would more accurately be called food HYPERsensitivity.  Like an allergy a food sensitivity is immune-mediated, but different antibodies (IgG) are involved such that it is completely non-allergic.  Food sensitivity symptoms can occur anywhere in the body and include joint pain, foggy thinking, hyperactivity, fatigue, poor digestion, body aches, eczema and other rashes, headache, behavior problems, weight gain or weight loss, TMJ and many more.  Food sensitivity symptoms might not show up for days after ingesting the food, and can last for weeks or in some cases, months.  As a result, these are often the hardest to identify.

Allergies, intolerances and sensitivities hold in common that they can be responsible for symptoms a person might have never connected to their diet.  They also share that elimination of the trigger results in improvement, and that the patient can, along with his or her naturopathic doctor, do a lot of work to decrease or even eliminate their reactivity by balancing the immune system and improving the strength and integrity of the digestive system.

Celiac disease stands in a class of its own, neither an allergy, intolerance or sensitivity.  In celiac disease, exposure to the grain protein “gluten” causes the body to mistakenly launch a destructive attack on itself.  There is some evidence that other auto immune diseases are similarly triggered or worsened by cross reactivity to offending foods, and so patients suffering from autoimmune conditions are often recommended to avoid common sensitivities.

Stay tuned for Food Allergies Explained Part 2 (Do I have one?), Part 3 (Testing), and Part 4 (Treatment).