Food Allergy vs Food Intolerance- What is the difference

Food Allergy vs Food Intolerance- What is the difference

Table of Contents

What happens when your food is not compatible with your body? Do you experience gastrointestinal issues or bloating and fatigue when you eat? Or maybe you suddenly get skin rash or migraines when you eat your beloved takeout? Don't worry; you are not alone. 

Statistics show that up to 26 million Americans may suffer from a food allergy vs a food intolerance, and over 65 million may suffer from a food intolerance. However, these statistics may be on the low side because some people are not properly diagnosed. 

The symptoms of a true food allergy vs a food intolerance are different from those caused by an intolerance. Allergies can be severe and life-threatening, involving the immune system. Food intolerances are generally milder and do not involve the immune system. Food intolerances usually involve the cells, digestive system, or a deficiency in a particular enzyme, which means that particular food isn't being broken down and digested properly by the body. Lets look at the key differences between an allergy vs a food intolerance. 

What is a food allergy?

A food allergy can cause severe symptoms in some people, such as anaphylaxis. Allergic reactions can occur even from the smallest amount of the offending food item, triggering a range of immediate responses. Food allergy reactions can take seconds to minutes to show signs and symptoms. 

What are the symptoms of a food allergy vs a food intolerance?

Milder allergic reactions to a trigger can be: 

  • Coughing
  • Wheezing 
  • Itching
  • Runny or stuffy nose
  • Watery red or puffy eyes

More severe allergic reactions to a trigger can be: 

  • Tingling in the mouth
  • Swelling of the lips, tongue, face, or throat
  • Hives
  • Anaphylaxis

Anaphylaxis symptoms: 

  • Constriction and tightening of the airways
  • Shock with a severe drop in blood pressure 
  • Dizziness or lightheadedness and sometimes a loss of consciousness
  • Fast racing heartbeat or pulse

It is essential to rule out allergies first by consulting your medical professional.

Why do allergies develop? 

Why do allergies develop?

Food allergies can develop at any time. However, they are more common in young children and usually can be lifelong. Scientists do not yet fully understand why or how someone develops allergies. The most common foods which may cause allergies: 

  • Wheat 
  • Soy 
  • Eggs 
  • Dairy
  • Peanuts
  • Shellfish or fish 
  • Tree Nuts 

When to see a doctor 

See your allergy specialist or doctor if you notice symptoms resembling a food allergy. However, you must seek urgent emergency treatment if you start to develop signs or symptoms of anaphylaxis.  

How is an allergy tested vs a food intolerance test?

Allergies are usually identified via a blood sample, skin prick, or scratch test. A blood sample is required to identify the immune system's response to the suspected trigger. The allergy test will determine the reaction of your immunoglobulins (IgG, IgE, IgM, IgA) in the blood when that particular trigger item is mixed. Doctors may also use blood tests to help identify immunodeficiencies (i.e., when the immune system isn't working as it should).

 What is food intolerance or food sensitivity?

Intolerances, commonly referred to as food sensitivities, can have delayed response time and usually involve the digestive system or cellular reaction to a particular trigger. Reactions can take between hours or days to show signs. The delayed onset of responses from a food intolerance may mean that food intolerances may be harder to identify due to the many different single items a person may have been exposed to or consumed within that period. 

What are the symptoms of food intolerances?

What are the symptoms of food intolerances?

Food Intolerance symptoms may range from:

  • Digestive issues, such as constipation, bloating, flatulence, gas, and diarrhea
  • Excess mucus in the throat or nose
  • Joint pain or inflammation of the muscles
  • Skin conditions, such as acne, rosacea, psoriasis, and eczema
  • Weight gain, or water retention
  • Decrease energy and lethargy 

How is a food intolerance tested?

Food intolerances may be tested in various ways:

Hydrogen breath test 

The hydrogen breath test is a medical test measuring hydrogen gas levels (H02) in a person's breath. When the body is not breaking down sugars from lactose (milk protein), glucose (sugars from carbohydrates), or fructose (sugar's from fruits), it is then fermented by bacteria in the small intestine and the colon. 

The hydrogen is absorbed from the intestines, carried through the bloodstream to the lungs, and exhaled. This is an excellent option for people who want to target dairy, gluten, and fruit intolerances. 

Food Diary / Self-Elimination Diet 

An elimination diet involves noting down all the food and drinks consumed daily and monitoring any reactions that may occur over a few hours to a few days. You can buy a food diary online or use food diary apps to track every item to start a food diary. 

Food Sensitivity or Intolerance Test

At-home food sensitivity testing kits require a person to submit a sample, which could be:

  • blood from a skin prick test
  • strands of hair
  • a mouth swab

It may take up to several weeks to receive the results.

Advanced Food Intolerance Labs kits

Why do food intolerances develop? Why do food intolerances develop?

The most common reason food intolerances develop is the absence of a particular enzyme, which can cause improper digestion and uncomfortable symptoms. Every food item which is consumed requires a certain enzymatic process to break down that food fully and then absorb the nutrients from that food. For example, the lactose found in milk cannot be broken down if there is a lactase deficiency. The sugar found in lactose remains undigested and intact, causing the bowels to ferment the sugar found in lactose resulting in bloating and gas. This fermented process can often trigger a lactose intolerance. 

Lactose intolerance has been found to be very common in North America. Research has found that through evolution, the population is genetically programmed to lose their lactase enzymatic ability after a certain childhood age. There is still hope! Depending on the level of symptoms, you may still be able to ingest lactose-based foods (such as milk and cream) if a lactase digestive enzyme is consumed with every lactose-based meal to help break down the lactose. 

Other conditions of a food sensitivity or a food intolerance: 

  • Caffeine Sensitivity - when people produce less of a liver enzyme called CYP1A2. This plays a role in how quickly the liver metabolizes caffeine.
  • Sulfite Sensitivity - this is when people may have a partial deficiency of the enzyme sulfite oxidase, which helps break down sulfites in food items such as dried apricots, canned fruits, wine, and cereals.

  • FODMAPS - when a group of sugars ferments in the digestive tract due to an imbalance in bacteria. Enzymes such as amylase and glucoamylase, cellulase, lactase and invertase, and other enzymes break down FODMAPs. FODMAP foods include beans and lentils, some vegetables such as onions, garlic, and cauliflower, some fruits such as apples, cherries, and mango.
  • Sucrose intolerance - Sucrose intolerance or genetic sucrase-isomaltase deficiency (GSID) is the condition in which sucrase-isomaltase, an enzyme needed for proper metabolism of sucrose (sugar) and starch (e.g., grains), is not produced or the enzyme produced is either partially functional or non-functional in the small intestine. Sucrose is found in sugar, sugary drinks, fast food, and baked goods.
  • Fructose intolerance - alterations in the ALDOB gene can cause hereditary fructose intolerance. The ALDOB gene provides instructions for making the aldolase B enzyme. This enzyme is found primarily in the liver and is involved in fructose breakdown (metabolism), so this sugar can be used as energy. Fructose is found in most fruits.

  • Sugar alcohol sensitivity (sorbitol, mannitol, maltitol, lactitol, isomalt) - this is when a series of sugar alcohol enzymes are deficient in the body, causing bloating and gastrointestinal distress. Sugar alcohols are found in most jellies, candies, ice creams, chocolate, chewing gums, protein powders, prunes, and berries. 

The Takeaway 

There are significant differences between food allergies vs intolerances to be aware of. Food allergies affect the immune system, and food intolerances involve the cells and the digestive system. While food intolerances may not be life-threatening, food allergies can be, and this is why it is essential to rule out allergies first and foremost. 

It may also be possible that you may not be allergic to a certain food item but intolerant, and vice versa. This is because the immune system can react differently to the digestive system and cells of the body. 

Food allergies can happen quickly and can be triggered even by the smallest portion of food. In contrast, food intolerances vs allergies, may require more significant amounts of that food intolerance trigger and can take between hours and days to show signs or symptoms.

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Author: Dr. Sony S. | Panel Expert, Medical Doctor Dr. Sony is known for her medical articles, written with in-depth detail and accuracy owing to her vast medical knowledge and thorough research of each article. She completed her degree with multiple scholarships from Guangzhou Medical University and is a board-certified Clinical Doctor. She is currently working as a Medical Officer in the emergency department of a renowned hospital and continues to publish numerous medical papers and articles. Dr. Sony continues to lead the way in medical breakthroughs, unparalleled by her high level of detail, knowledge and passion for discovering new sciences and innovative healthcare treatments.

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