Food allergy, food sensitivity, and celiac disease: An expert explains the key differences

If you are experiencing uncomfortable symptoms such as bloating, migraines, headaches, indigestion, gastrointestinal distress, or stomach pain, you’re probably wondering if a certain food in your diet could be responsible. And while many folks have been able to narrow down their culinary culprits by way of partnering the actionable results of our Food Sensitivity Test with a two-part elimination diet, we’re interested in breaking down some of the misconceptions around food-related conditions more clearly.

While it’s true that food sensitivities can make you rather uncomfortable, it’s important to note that food allergies can be potentially life-threatening. That’s why it’s important to be aware of the differences between the two, and know what symptoms to look out for.

RELATED: Food Sensitivity Explained

To better understand the differences between food sensitivity, food allergies, and another well-known but often misinterpreted autoimmune response known as celiac disease, we spoke to Registered Dietitian Nutritionist and Everlywell Consultant, Heather Hanley.

Below, Heather cuts through the confusion to break down the distinctions between symptoms between these three food issues, available testing options, and how to best deal with them:

Food Sensitivity

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What is it? A food sensitivity is an adverse reaction to a food. Food sensitivities can resolve after a period of abstinence and they are not life threatening.

What are the symptoms? While symptoms can vary quite a bit, some of the most common include:

  • Digestive discomfort or bloating
  • Gas
  • Diarrhea or constipation
  • Headaches
  • Migraines
  • Stomach or abdominal pain

How long does it take for symptoms to appear? Unlike the timeline of a true food allergy, symptoms from a food sensitivity can appear up to 72 hours after ingesting the trigger food.

What does diagnosis look like? A two-part elimination diet is the gold standard of testing for a food sensitivity. You can use Everlywell’s at-home collection kit to test your body’s IgG reactivity to 96 common foods and will receive results for each food rated on a scale of normal to high reactivity. From there, you’ll be guided towards the foods to priority during a two-part elimination diet, in order to help identify which foods might be causing your symptoms.

How can someone diagnosed with a Food Sensitivity best manage it? Initial treatment is to avoid the offending food. Then, an elimination diet is recommended for a period of time and the food is reintroduced into the diet as you monitor symptoms for any adverse reaction. Usually problematic foods can be re-introduced after a period of elimination with the caveat that perhaps they are consumed less frequently. In short, testing for Food Sensitivity with Everlywell helps expedite this process.

Food Allergy

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What is it? A food allergy is an IgE immune response to a specific food that triggers a histamine reaction with potentially severe symptoms. Some of the most common foods known to cause an allergic reaction are: peanuts, tree nuts, milk, egg, fish, shellfish, wheat, and soy.

What are the symptoms? A true food allergy to a specific food can result in potentially life-threatening symptoms, like anaphylaxis, and has a nearly immediate reaction time. Symptoms can include:

  • Hives or itchy skin
  • Stuffy nose, sneezing, itchy, or watery eyes
  • Vomiting, diarrhea, or stomach cramps
  • Swelling
  • In extreme cases, anaphylaxis, which can be life threatening.

How long does it take for symptoms to appear? Usually reactions are immediate, within a few minutes, although some can experience reactions a few hours later. Some people also experience a reaction referred to as Oral Allergy Syndrome[1]. This is a result of cross-reactivity, for example, if someone has a latex allergy, they can experience a reaction when they ingest avocados, kiwi or bananas. People who have pollen allergies can also experience reactions to certain fruits and vegetables.

What does diagnosis look like? There are a few different methods to help determine a food allergy:

  • Skin Prick Test or Intradermal Skin Test - a positive skin prick test alone does not necessarily diagnose an allergy, nor does it indicate the severity of an allergy.
  • Blood specific IgE test
  • Physician supervised challenge test
  • Patch test

How can someone diagnosed with a Food Allergy best manage it? The first line of defense is to avoid the offending food(s). Currently, Oral Immunotherapy and Sublingual Immunotherapy are being studied for treating food allergies. (Environmental allergies are treated with allergy shots or sublingual immunotherapy.)

It’s worth noting that many children outgrow some — if not all — of their allergies, however, it is possible for adults to develop allergies. A 2019 study in published in JAMA[2] estimates 10.8% of the US adult population have one or more food allergies. Celiac Disease

Celiac Disease

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What is it? Celiac disease is an autoimmune disease, also known as celiac sprue or gluten-sensitive enteropathy. Current estimates suggest that 1:100, or 1% of the population in the United States is affected and if left undiagnosed, it can damage the small intestines resulting in malabsorption of nutrients which in turn can lead to other disorders.

What are the symptoms? Some of the symptoms of celiac disease include:

  • Bloating or gas
  • Abdominal pain
  • Diarrhea or constipation
  • Nausea or vomiting
  • Weight loss

In adults, symptoms may also include:

  • Anemia
  • Mouth ulcers
  • Headaches
  • Fatigue
  • Joint pain
  • Skin rashes/dermatitis herpetiformis (seen in approximately 10% of those diagnosed with celiac disease)
  • Numbness
  • Cognitive impairment

How long does it take for symptoms to appear? It can take weeks or even years to diagnose celiac disease. It’s often diagnosed in childhood, with most children with celiac disease having a close relative with the disorder[3].

What does diagnosis look like? There are a few different ways that celiac disease can be determined:

  • Physical assessment of the person including symptoms listed above and manifestations of malnutrition
  • Biopsy of the small intestine
  • Capsule endoscopy, where a wireless camera is ingested and travels through the digestive tract recording pictures
  • Serology testing includes testing for tissue transglutaminase (tTG) IgA and IgG, endomysial antibody (EMA) IgA, deamidated gliadin peptide (DZPG) IgA and IgG
  • Genetic testing for HLA-DQ2 or HLA-DQ8. (All people with celiac disease have one of these gene variants found in approximately 30% of the populations. If this variant is not present, it’s unlikely that someone has celiac disease)

How can someone diagnosed with celiac disease manage it? Once diagnosed with celiac disease, it’s critical to follow a strict gluten-free diet. Even miniscule amounts from cross-contamination in food preparation can cause problems for patients with celiac disease.

Want to learn more about how your body responds to certain foods? Our Food Sensitivity Test shows your body’s IgG (antibody) reactivity to 96 foods to help guide you on what types of food may be the best to choose for a two-part elimination diet.

If you’re wanting to gain insight into your body’s IgG (antibody) reactivity to even more foods (hello, adventurous eater!), check out our Food Sensitivity Comprehensive Test. It tests an even broader range, so you can measure IgG antibody response to 204 common foods that may be causing you discomfort and help you take action on your symptoms.

Related Links:


1. Oral allergy syndrome (OAS). American Academy of Allergy Asthma & Immunology. URL. Accessed April 13, 2022.

2. Prevalence and Severity of Food Allergies Among US Adults. JAMA. URL. Accessed April 13, 2022.

3. What is Celiac Disease? Celiac Disease Foundation. URL. Accessed April 13, 2022.

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