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Food Allergy vs. Sensitivity vs. Intolerance: Major Differences Compared

Food Allergy vs. Sensitivity vs. Intolerance: Major Differences Compared

Have you ever wondered what is the difference between a food allergy, sensitivity, and intolerance?  Have you contemplated whether a specific food or food family was the culprit for your low energy or fatigue, poor, sleep,  deadly gas, constipation, skin/hair/nail issues, etc.?

Since approximately 70-80% of our immune system can be found in the gut, there is a pretty good chance that a food allergy, sensitivity or intolerance is, in fact, the reason you are not feeling you’re very best.[1] The tricky part about this whole concept is that most healthcare professionals are not educated on the topic of adverse food reactions and even those who are, do not completely understand the difference between a food allergy, food intolerance, and food sensitivity. I hope this article will shine a bit of light on the subject.

Let’s start with food allergies since this is a term most people recognize.

Food Allergy

A true food allergy involves the immune system. This reaction is commonly referred to as a Type I Immunoglobulin E (IgE) Hypersensitivity response. An allergic reaction occurs when your body mistakes a “safe” protein for an invader and begins to attack the food item that contains the protein.3 Your body then releases an organic nitrogenous compound known as histamine as a way to “fight” the protein. When histamine is released, your body may react by experiencing hives, coughing, vomiting or wheezing. Although most food allergies appear during early childhood, it is very much possible for an adult to suddenly experience this reaction.

It is important to note that a food allergy will always occur shortly after consumption. Typically the symptom(s) can be detected within minutes but for some individuals, it may take a few hours before the individual feels symptomatic. The reaction is typically severe in nature.

The most common symptoms of a food allergy include but are not limited to: wheezing, coughing, vomiting, difficulty breathing or a closed airway/tightening of the throat, hives, severe abdominal pain, rash, itchy or swollen tongue.

Surprisingly, just 8 foods cause a majority of food allergies. The most common sources of food allergies include but are not limited to: milk, wheat, egg, corn, soy, fish, shellfish, tree nuts (particularly peanuts).[3]

Food Sensitivity

The term food sensitivity is often used interchangeably with food allergy even though they are completely different immune reactions! A food sensitivity is often referred to as a delayed hypersensitivity response, meaning that the individual may not present with symptoms until several hours or even several days later.  A food sensitivity is also very dose-dependent. As you can imagine, this makes food sensitivity detection a bit more difficult than an allergy

Do you have acid reflux or frequent GI upset after eating? This may be due to a food sensitivity or intolerance.

While a food sensitivity also involves the immune system, the method of action is separate from a food allergy. A food sensitivity includes every immune response other than a Type I Hypersensitivity response. The most common sensitivity reaction to foods includes Type 3 Immune Complex Mediated Hypersensitivity and Type 4 Cell-Mediated Hypersensitivity.5 Food sensitivities are much more common than food allergies and they typically occur as a result of a gastrointestinal system imbalance, most commonly referred to as intestinal permeability.

Intestinal permeability occurs when the lining of the gut has been disturbed by the outside world. Processed foods, certain medications, pathogens, toxins, and stress are the biggest offenders. As we age, our immune system struggles to carry the load, thus leading to intestinal permeability. Food particles that should be contained in the intestines suddenly start to slip through the lining and then magically appear in your bloodstream. Your body realizes that the food should not be in your bloodstream and as a result, it begins to attack the particles. My athletes often say to me, “But I have been eating ___ my entire life!!! How could I possibly be sensitive to that food all of a sudden??” The answer is that your gastrointestinal system is likely out of balance because of what it has been exposed to over the years and now your body is fighting back.

Conditions commonly exacerbated by food sensitivities include but are not limited to: Fibromyalgia, IBS, migraine, eczema, Autism Spectrum Disorders, Arthritis, Chronic Fatigue, Urticaria.[1]

The most common symptoms of a food sensitivity include but are not limited to: headaches, nasal drip or congestion, excess mucus production, fatigue, irritable bowel, acne, muscle or joint pain, nausea, reflux, dark circles under the eyes, bladder control issues, bloating, mood swings, dizziness, difficulty sleeping, anxiety, depression, dry skin and excessive sweating. Now if you experience one of these reactions from time to time, it’s probably nothing to worry about but if this is something you experience on a routine basis, you may want to strongly consider keeping a close eye on your diet. It’s amazing what you might be able to detect!

The most common food sensitives are corn, dairy, wheat, egg, and soy, however, there is no limit as to what an individual can react to. It is entirely possible to have this type of reaction to broccoli, blueberries, legumes, grains, cilantro and beyond!

Food Intolerance

Last but not least, a food intolerance is the least severe of the three possible reactions. Food intolerance does not involve the immune system and typically stems from a reaction to a component of a specific food vs. the food item itself. For example, an individual may react to lactose, the sugar in milk or lectins which are indigestible proteins found in certain foods such as legumes and grains. A food intolerance occurs when our body lacks a certain nutrient or enzyme needed to break down that particular component of the food.[1,5]

The symptom(s) of food intolerance are typically immediate and occur more quickly than a food sensitivity, but are not as severe as an allergic reaction.

The most common symptoms a food intolerance include but are not limited to: flushing, diarrhea, general discomfort, and cold or flu-like symptoms.

The most common foods/food components are known to trigger a food intolerance include but are not limited to: histamines, lactose, lectins, preservatives, alcohol, artificial fillers, flavorings, and colors, acidic foods, citrus fruits, and sulfites.

Now that you know the difference between a food allergy, sensitivity, and intolerance you can take better control of your health. If you suspect an allergy, schedule an appointment with your local allergist. If you suspect a food intolerance or sensitivity, start to keep a food journal and track all symptoms. MySymptoms app is one of the most convenient trackers when it comes to food reactions.  After 3-4 weeks of tracking, there is a good chance you will be able to detect a pattern. If it’s still confusing, schedule an appointment with a dietitian in your area and share your log during your visit.

Just remember, the sooner you pinpoint your reactive food(s) the sooner you will be able to calm the inflammation in your body. The better you are able to calm the flames of inflammation, the better you will recover post-workout, heal when injured, and prevent chronic illness long term!

What has been your greatest challenge or issue with a food allergy, sensitivity, and intolerance?  Leave some of your thoughts in the comments below or feel free to contact us directly if you’re interested in a virtual consult!


  1. Taylor, S., S. Hefle. Food Allergies and Other Food Sensitivities, Food Technology., September 2001, Volume 55., NO 9
  2. Farré R, Tack J. Food and symptom generation in functional gastrointestinal disorders: physiological aspects. Am J Gastroenterol2013; 108: 698–706.
  3. O MH, Wong WH, Chang C. Clinical spectrum of food allergies: acomprehensive review. Clin Rev Allergy Immunol 2014;46: 225–240.
  4. Bischo  S, Crowe SE. Gastrointestinal food allergy: new insights into pathophysiology and clinical perspectives. Gastroenterology 2005; 128:1089–1113. doi: 10.1053/j.gastro.2004.08.015
  5. Francesca Pasqui, Carolina Poli, Antonio Colecchia, Giovanni Marasco, Davide Festi, Adverse Food Reaction and Functional Gastrointestinal Disorders: Role of the Dietetic Approach,

About The Author

Kylene Bogden

Meet Kylene Bogden, a trailblazer in sports nutrition and the Performance Dietitian/Nutritionist for the Cleveland Cavaliers. With a prestigious background that includes contributions to the renowned Cleveland Clinic Center for Functional Medicine, Kylene holds certifications from the Integrative Functional Nutrition Academy and is a Certified LEAP Practitioner for food sensitivities. Notably, she is also a Certified Specialist in Sports Dietetics. Kylene's holistic approach to nutrition sets her apart in the field, making her a go-to authority. Her collaborative work with players, coaching staff, and medical professionals has solidified her reputation. Kylene's expertise has been recognized by major publications, including features in Vogue, Women's Health, STACK, and other prominent websites, where she shares evidence-based strategies to fuel peak athletic performance. Beyond accolades, Kylene is an educator, actively engaged in initiatives promoting health and wellness. With a personal commitment to a well-rounded lifestyle, Kylene, alongside her husband Dr. Bogden, exemplifies the transformative power of nutrition. In the dynamic world of sports nutrition, Kylene Bogden's unparalleled expertise continues to elevate both individual athletes and the Cleveland Cavaliers to unprecedented levels of success. As a high school and collegiate sprinter, she experienced recurrent injury and fatigue. After years of constant struggle, she eventually learned that an abundance of processed foods and poor fueling strategies were the root of her performance issues. Kylene's personal journey as an athlete fueled her passion for finding a more progressive approach to sports nutrition. Since then, she has helped thousands of individuals dramatically improve overall health and athletic performance by taking a whole food approach.


  1. Millie Hue

    Thanks for helping me understand that food intolerance is the least among the three since it just means that there is a lack of an enzyme in the body which keeps you from breaking down the certain food. I guess this is what I have because I can still drink those with a small amount of milk in them, but I can’t totally drink pure milk. Whenever I drink pure milk, I would really have stomach pain which keeps me from going to work at times. I should see a specialist to diagnose this if I am really not able to break down milk.

    • Michael Bogden

      Thanks for your thoughts and for taking the time to check out our article, Millie! We’re sorry to hear that milk is causing you stomach pain but we totally agree it would be great to see a specialist!

  2. Dawn E Wade

    I am highly allergic to citric acid in any form. Contact with any citric product burns my skin instantly. The more I am around it the worse I get. I once worked at a pizza parlor, for three weeks, preparing pizza to cook. Unrelated I took my daughter to a wic appointment and the worker wanted to notify the athorities to confict whomever may have assaulted me. I was diagnosed as being allergic to oranges while my mother was still breastfeeding me. She noticed my butt would scab up for apparently no reason. She asked the Dr and he said to stop drinking orange juice and in two days time I would have no problem with diaper rash. I have noticed over my 39 years that the times I would unknowingly consume citric acid containing I would have a rash where I sweat. Very inconvenient, I found that corn starch helps ease the rash. I just would like to share that a substitute for lemon(not for flavor), when making cake Frosting or Mayo or coloring eggs, is vinegar.



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Family picture of Dr. Michael Bogden and licensed dietitian nutritionist Kylene Bogden

Meet Kylene & Dr. Michael Bogden

Kylene is a licensed dietitian nutritionist board-certified in sports nutrition as well as Integrative and Functional Nutrition. She is a certified food sensitivity LEAP therapist and the Performance Dietitian for the Cleveland Cavaliers. Michael, a physiotherapist with dual fellowships, merges sports nutrition with rehab to enhance client recovery.

Together, they've conquered personal health challenges that hindered their athletic pursuits including mold toxicity, Celiac disease, SIBO, and food sensitivities. Inspired by their journey, they founded a thriving private practice in 2017, now boasting three expert-trained dietitian nutritionists specializing in functional nutrition.

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