Skip to content
Allergy Sensitivity Intolerance - What are the Differences?

By Dr. Ruth Moore

In today’s cyber world, there are multiple advertisements for food tests.  All these advertisements promote self-testing to learn about Allergies, Sensitivities, and Intolerances.  It is no wonder that people are confused.  The two most common questions that I field as a practitioner are what are they, and what are the differences between them?  The simplest way to answer these questions is to identify what they are from a clinical perspective and then compare them. 

Most people grow up believing that they have food allergies, but rarely do they learn about Sensitivities or Intolerances – all of which can affect their health, wellness, and well-being.  What is confusing is that they all have overlapping symptoms and the terms are used interchangeably, even though they should not be.

What are the key differences?

Allergies are the histamine reactions that occur with consumption of certain foods and can be life-threatening; however they MUST be diagnosed by providers after symptoms are clinically evaluated and treated with medications (usually antihistamines and steroids).  

An allergy is the body’s immune response to protect itself. People most often attribute these reactions to food items, but other reactions can occur to environmental exposures like latex, hand lotions, perfumes, and aerosolized proteins from pollen or fish / shellfish as it is cooked. 

In a true allergic reaction, the onset of symptoms usually happens very quickly – from a few minutes to a couple of hours after exposure.  Delayed onset can happen usually from 6 hours to a couple of days after exposure – so a true diagnosis can be very difficult with the passage of time. There are varying reactions, that range from mild redness and urticaria (bumps and rashes) from skin contact to full systemic shutdowns (anaphylaxis); but all are determined by IgE (blood testing) or skin allergen testing (less reliable) – and the latter can be most unpleasant as people endure symptoms from the release of histamine and other inflammatory cells called Cytokines. 

Food Sensitivities are just that, the body’s potential sensitivity to food items.  Most sensitivities are determined by analysis of the IG markers to proteins found in human blood.  These can be diagnosed as allergies if the body has a histamine reaction, but more likely than not, they will merely cause symptoms of flatulence, bloating, and general malaise.

Food intolerances are the body’s physiological responses to foods that cannot be properly digested.  According to the Cleveland clinic this is because the body does not have the ability to produce certain enzymes.  Although not immediately life threatening, intolerances can have a cumulative effect that can impact the body and a person’s health, over longer periods of time.

Both Sensitivities and Intolerances are physiological responses (without histamine responses) that do not pose an immediate, life-threatening risk.  They do cause discomfort, however, with bloating, pain, nausea and indigestion, or general feelings of malaise. There are a number of different types of sensitivities and intolerances, which again can lead to confusion as their symptoms overlap.

What are the most common symptoms?


The symptoms of most true allergy reactions include:

allergy symptoms

  • Rashes, hives, skin changes
  • Itchy mouth, throat
  • Swelling of the lips or face
  • Coughing or sneezing
  • Watery eyes or runny nose
  • Vomiting or diarrhea
  • Worsening of asthma or eczema
  • Anaphylactic shock 

Food Sensitivities and Intolerances:

A list of commonly reported symptoms that are associated with food sensitivities include: 

  • Bloating, Flatulence, and Cramps caused by excess gasses building up in the intestines and stomach.
  • Changes in bowel movements with either loose and watery or hard and constipated stool.  This is because the intestines and colon are not functioning properly.
  • Fatigue from nutritional and energy deficiencies.  Our bodies derive energy from food by digesting nutrients and producing ATP to regulate the heart and neural connections.
  • Headaches and Fogginess from neurotransmitter imbalances and fluctuating hormones.  

Less commonly reported symptoms that are associated with food sensitivities include:

  • Behavioral changes that can look like irritability and anger.
  • Cognitive changes that affect attention, focus, and perceptions.

Experts and both the Mayo and Cleveland Clinics recognize that if a person has sensitivities or intolerances, they may be able to eat “small amounts of the offending food without trouble.”  Likewise, some people are completely asymptomatic with food sensitivities and intolerances, until their systems are overloaded with hormones that are secreted or expressed over time, and are attributed to other issues.  

What are the three most common food sensitivities and intolerances?

Lactose: People who are lactose intolerant don’t make enough lactase enzyme to break down lactose, a sugar found in milk and dairy products. This intolerance also can indicate a greater problem with the ability to digest many different types of sugars and can be an indicator of developing potential Type II diabetes issues at a later date.

lactose intolerance

Histamine: Histamines are naturally occurring chemicals in foods like cheese, pineapples, bananas, avocados and chocolate. Red wine and some white wines also have histamines. People who are histamine intolerant don’t make enough diamine oxidase enzyme to break down this chemical.  If a person has a histamine intolerance, they will generally have allergy symptoms (runny nose, congestion, headaches, lethargy, and sneezing) every day, as their body systems will be triggered by both foods and environmental irritants, and more often than not, these symptoms will be attributed to hay fever or other label rather than the foods they are eating.  

Gluten: Gluten is a protein in wheat, rye, oats, and barley. Gluten sensitivity isn’t the same as having celiac disease, a type of autoimmune disease. When you have celiac disease, gluten damages the small intestines. If you have a non-celiac gluten sensitivity, your body has a harder time digesting gluten, and eating many different types of grains or consuming grain alcohols can trigger reactions.  

The scientific and health communities are well aware of these intolerances, and state that there are few reliable tests like hydrogen breath tests to identify intolerances; however they also market the concept that through self-diagnosis via targeted marketing and advertising, a person may be able to prevent these reactions. 

One of the most common examples of non diagnosis is the diagnosis of lactose intolerance.  Doctors will not often recommend IG testing for intolerance symptoms, because the intolerance is based on the body not being able to digest lactose, a sugar molecule found in milks. If people have symptoms of cramping, bloating, and diarrhea, rather than seeking medical interventions and testing, they are encouraged to consume lactose-free milk products or take lactase enzyme pills (Lactaid) to aid digestion.

Self help groups that specialize in juvenile conditions like ADD, ADHD, and Autism Spectrum disorders have known for years that certain foods can contribute to intolerances and symptoms.  They have attracted millions of followers and recommend specialized diets like FODMAPs. These diets, while effective for many, can also have unforeseen consequences to the development of other conditions, because they use a one-size approach and are not nutritionally sound for human growth and development.  

If food sensitivities and intolerances are not recognized and are untreated, they can also contribute to symptoms that lead to the diagnosis of chronic conditions. 

These physiologic conditions attributed to food intolerances are irritable bowel syndrome, chronic fatigue, arthritis, autism and ADD/ADHD.  These are usually because the body has an absence of an enzyme needed to fully digest a food or a sensitivity to food additives.  When I work with test interpretations, I look for many data points in food intolerances and potential nutritional imbalances to see if there are deeper underlying physiological issues that can be addressed through dietary and environmental changes.

At 5Strands Affordable Testing, we know that most food sensitivities or intolerances often can be overcome through the implementation of an individualized elimination diet and then relearning how to eat a personalized moderation diet to improve gut health. The process of eliminating foods is a generally accepted practice that gives the digestive system time to ‘rest’ and the gut can balance its flora to heal. A moderation diet, likewise allows a person to relearn how to eat to derive the best possible health benefits of their foods.

The 5Strands Health Assessment Includes 4 Functional Health Tests that help you take the first steps on your wellness journey:

5strands health assessment

Learning about how your body responds to your current dietary & lifestyle decisions has never been easier. YOUR RESULTS create a SPECIFIC, INDIVIDUALIZED PATHWAY to BETTER HEALTH!


  • Maria   |  

    This answers all my questions! Thank you!

  • Kathrine J   |  

    Hello, I no these don’t get many comments yet. But they will. Your company keeps putting good content and I am learning a lot. Thank you

Leave a comment

Please note, comments must be approved before they are published


    Check out our variety of tests for the whole family

  • HAVE A

    Check out our frequently asked questions


    Our team is available Monday - Friday, 9-5 EST


    Check here to view our official refund policy