Food Allergies, Intolerances & Sensitivities...What's the Difference?

Food Allergies, Intolerances & Sensitivities...What's the Difference?

Have you ever felt a tickle in the back of your throat after swallowing something? Or maybe an irritating cough after eating a certain food? You might be reacting adversely to this food. Adverse food reactions are a major contributor to inflammation and damage to the gut. Having a reaction to foods also diverts precious immune system resources away from its main job – protecting the body from pathogens.

There are three common types of adverse food reactions: allergies, intolerances, and sensitivities. Adverse food reactions manifest in slightly different ways in the body in response to exposure to some type of ingested food antigen, but the immune system is always programmed to react.

What is a food allergy?

A food allergy occurs when a person’s immune system immediately reacts by generating antibodies to a food as soon as they start chewing (and sometimes even if the food is nearby). Some of the most common allergenic foods include shellfish, dairy products, wheat, corn, soy, eggs, strawberries, chocolate, and peanuts are right up there too. If you are allergic to any of these food items, you’d probably know it by now as you definitely need to avoid consuming them to avoid the harsh symptoms associated with this immediate (Type 1) sensitivity such as hives, asthma, or anaphylaxis.

What is a food intolerance?

Food intolerances are essentially an inability to digest a specific food usually due to a lack of a certain enzyme or enzymes. Lactose intolerance (the most common) occurs when an individual is deficient in lactase, which helps break down lactose – the sugar found in milk. Another common deficiency is an absence of alpha-galactosidase, which is the enzyme that helps break down the carbohydrates in legumes and beans.

What is a food sensitivity?

Food sensitivities are complex non-allergic, non-celiac inflammatory reactions that can involve both innate and adaptive immune pathways. These delayed—harder to detect—reactions essentially come and go based on the health of your gut and overall toxic load on the body. Because when the lining of the intestinal tract becomes irritated by too much alcohol, stress, sugar, gluten, antibiotics, or processed food, small perforations form, making it more permeable (“leaky gut”). Now you have particles of undigested food (antigen) able to enter the bloodstream, contributing to inflammation and eliciting an immune response.

Okay, now let’s get a little science-y… Once the immune system perceives the food antigen as an invader or enemy, a series of physiological events are triggered by mechanisms—of which there are three categories:

      1. Humoral: an immune-driven mechanism—where antibodies and the complement system are developed—that triggers mediator release. The complement system enhances the immune system and enables antibodies and phagocytic cells to clear the perceived invader from the system.

      2. Cell-mediated: involves the activation of phagocytes and T-lymphocytes that then release various cytokines in response to an antigen. No antibodies are involved here.

      3. Non-immune: this mechanism involves lectins—which are naturally occurring in certain foods (nightshades, legumes, and more) and histamine-containing foods. These mechanisms bind to receptor sites of white blood cells to trigger mediator release in people with sensitive systems and/or have improper digestive capabilities of these specific foods.

Mechanisms cause the release of mediators (from white blood cells) during the “defense” phase of a hypersensitivity reaction. Mediators get involved during the chemical warfare phase of a hypersensitivity reaction—and are ultimately what cause the manifestation of an inflammatory response, smooth muscle contraction, and more apparent symptoms such as diarrhea or constipation, bloating and gas, joint pain, eczema, or even migraines. Of the approximately 100 known types of mediators, cytokines and histamine are the most well-known. The mediator-caused symptoms are ultimately what make people miserable when they have an adverse food reaction.


Headaches, migraines, dizziness


Bleeding gums, coated tongue, bad breath, swollen lips

Dark circles under the eyes, runny nose, stuffy nose, mucous, hay fever, sneezing, ringing in the ears, earache, frequent “colds,” chronic cough

Depressed or excessive sexual drive, abnormal adrenal hormones and functions, menstrual irregularities, and symptoms

Heart palpitations, changes in blood pressure, asthma, bronchitis, yawning


High blood sugar, diabetes, increased liver enzymes

Stomach ache, acid reflux, bloating, nausea, belching, gas, diarrhea, constipation, malabsorption

Hives, rashes, dandruff, hair loss, eczema, psoriasis, dermatitis, skin issues


Fatigue, sleepy after meals, insomnia, compulsive eating, overweight, joint pain, arthritis, restless leg syndrome, urinary tract symptoms, chills, sweats, thirsty after meals, back pain

Anxiety, fear, depression, crying, aggressive behavior, irritability, brain fog, morning sluggishness



Pulse test

I always recommend collecting as many “clues” about your own body as possible. The below Coca Pulse Test is something you can do at home today to determine if your body is reacting adversely:


Using a watch with a second hand (mobile phones can skew results so place at least 10 feet away), sit down and relax for a few minutes before taking your pulse at the neck or wrist. You’ll want to count the number of beats for a full 60-seconds (or 30-seconds and multiply x2) – normal pulse readings are between 52 and 70 beats per minute (bpm). Now consume the food item in question (or even just place it in your lap) and wait 15 seconds before taking your pulse again. If the pulse total is different, subtract the smaller number from the larger number. If the difference is 6 or more, the item being tested is causing a reaction (inflammation) and should be removed from the diet for at least 1 month before testing yourself again.

The MRT Food Sensitivity Test is a functional wellness test that I use in my practice to measure inflammatory non-IgE reactions–food and chemical hypersensitivities (reliability is >90%). Food sensitivities – and the inflammatory effects they have on our bodies – can change after a period of avoidance, post-MRT testing. The goal of food sensitivity testing is to identify reactive foods and chemicals, eliminate them from the diet for a period of time in order to reduce inflammation and heal, and then slowly reintroduce the healthy, nutrient-dense foods we love without causing further suffering. But for anyone who has experienced the suffering food sensitivities sometimes causes, the reintroduction phase can come with a side of apprehension. Luckily, I have an easy-to-follow plan for that!

After the recommended avoidance period (3 – 6 months), it is time to reintroduce foods on the MRT-sensitive list, one at a time, so you can monitor yourself for symptoms. So, at the end of the recommended avoidance period, reintroduce a single food for one day only, then pay close attention to the way you feel and monitor for symptoms (like bloating, sleep disturbances, moodiness, skin breakouts, etc.) for three days. For example, if eggs were on your list of sensitive foods, you might decide to reintroduce them on a Monday. That day you could eat a veggie scramble for breakfast, deviled eggs, and then a frittata for dinner. It’s important to focus on one food at a time – and not make any other changes to the diet – for proper monitoring of reactions on Wednesday and Thursday. 

If on that third day, you’ve experienced no issues at all with it, this is an indication the food is now safe to eat on a rotational basis (not every day) and you may try reintroducing another MRT-sensitive food (maybe it’s coffee) on Friday. You can continue this process for each of the foods on your reactive list until you’ve determined what foods may cause you an issue (if any). If there is an adverse reaction, this food simply goes back on the MRT-sensitive food list for 3 months before it can again be put to this reintroduction challenge.

Eliminating all identified food sensitivities for a period of time can reduce stress on the immune system, decrease inflammation (helping to heal “leaky gut”), resolve food cravings, and reduce the potential for more chronic conditions down the road. If you are someone who has struggled with food intolerances or digestive issues, I recommend hiring someone like me (or just hire me!) to run functional wellness tests, do some investigating, then create a personalized nutrition plan that will address the root cause of your concerns and support your gut health.  

Have questions about working one-on-one with a holistic nutritionist, food sensitivities, or want to know more about functional wellness testing? Let’s jump on a FREE Discovery Call to see what your goals are and to see if we are a good fit to work together.

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