Food Allergies vs Sensitivities vs Intolerances

by | Jun 7, 2022 | Healthy Bites


Allergies vs Sensitivities vs Intolerance

Written by Bethany Goccia, Way of Life Nutrition & Fitness Dietetic Intern

Reviewed by Nicole Kerneen,RD,CD,CSSD

You’ve just finished a meal and within 30 minutes you are hightailing it to the bathroom.  What gives?  Are you just “sensitive” when it comes to digestion or could there be something else going on?   The urgent need to find a bathroom soon after eating is not just “your norm.”  It is an indication that something is going awry in your gut.  There are many reasons that could cause your gastronomic distress, and seeking out a qualified dietitian is a great way to get to the bottom of things.   For the sake of time, I am only going to focus on one of those many reasons – allergies, sensitivities and intolerances.

Many people claim to have an intolerance, sensitivity or even allergy to a certain food, but without understanding what that means.  So let’s define the terms.  An intolerance is exclusively a gut issue.  The most common one is lactose intolerance.  Lactose is a sugar that is found in milk.  An enzyme in the small intestine is what breaks the lactose down into its simplest form needed for absorption.  If that enzyme is missing or insufficient, the lactose does not get broken down and ends up fermenting in the small intestine, causing all kinds of unpleasant symptoms like bloating, gas, cramping and sometimes diarrhea.  Those symptoms usually come on within 1-2 hours after eating.

The word “sensitivity” is often used interchangeably with “intolerance”, but they are actually quite different.  A sensitivity to a food also causes a gut reaction with those same unpleasant symptoms, but this is accompanied by an immune response outside the gut.  The body identifies a specific food as an invader and mounts an immune response to attack the food.  This can lead to inflammation and/or pain elsewhere in the body.  Unlike an intolerance, these symptoms can manifest anywhere from a few hours after eating to a few days.  This makes it difficult (but not impossible!) to identify the offending food.

A true food allergy is often evidenced immediately after eating, but can sometimes take up to 2 hours to manifest.  Like a sensitivity, the body mounts an immune response to the offending food, but instead of attacking the food, the body attacks itself.  This can result in one or more of the following symptoms: swelling of the tongue, throat or lips; difficulty breathing; feeling lightheaded; clammy skin and/or hives; confusion and anxiety; losing consciousness.  When multiple systems are involved in the immune response, this is an anaphylactic reaction and must be taken seriously and acted upon swiftly.

As you can see, all 3 of these food-related conditions are similar and can easily be confused, unless of course you have immediate swelling and difficulty breathing.  None of them should be ignored, as these unpleasant symptoms are the body’s way of telling you that something isn’t right.  Finding the source of intolerance or sensitivity is necessary to restore optimal digestion and gut function.  And who wants to be running to the bathroom after eating anyway?  That is not a good way to live and you deserve better. 

So how do you get started toward better health and better gut health specifically?  First of all, DO NOT choose  any of the intolerance tests you see online.  They are notoriously unreliable and many people end up on extreme elimination diets by relying on those results.  Implementing an elimination diet is difficult for most people to do on their own and if there are a large number of foods being avoided, then you are setting yourself up for nutritional deficiencies and a slide into poor health rather than better health.  The best place to start is with a Registered Dietitian who is well-versed in GI issues.  They can help you determine if you need to see an allergist for legitimate testing or if your puzzle can be solved through dietary changes.  An RD is able to guide you through this maze of symptoms and come alongside you in your nutritional journey.   Remember, you don’t have to walk this journey alone.

If you are interested in working with me to look at your current intake and any possible symptoms you may be experiencing, feel free to make an appointment with the links below!

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Photo by Cristiano Pinto on Unsplash 


Meet Nicole

Registered Dietitian Nutritionist

Nicole is recognized state-wide and nationally as a Registered Dietitian and is also a Certified dietitian through the state of Wisconsin. She is also a Board Certified Sports Dietitian and a Certified Personal Trainer and Physical Fitness Instructor.

Nicole’s areas of expertise include: Wellness and lifestyle coaching, weight management, behavior modification, eating disorders, vegetarian lifestyles, gluten-free living, sports nutrition, recipe and menu design and development.







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