Food Allergies, Sensitivities and Intolerances - What's the Difference?

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Food Allergies, Sensitivities and Intolerances - What's the Difference?


Migraines. Eczema. Sinus issues. Diarrhea. Constipation. Muscle pain. What do these symptoms have in common? They are all forms of inflammation and most are reactions to foods or chemicals found in foods or the environment. But is it an allergy, a sensitivity or an intolerance? These words are often used interchangeably, but are not the same thing. Some may be potentially life-threatening, while others are just a chronic nuisance. How do you know which one it is and what you can do about it?


A food allergy is an immune-system reaction to a specific protein found in a food. The immune system sees this protein as a foreign invader and mounts a defense by producing antibodies to fight it. Symptoms occur quickly after consuming the food and can be life-threatening, as in an anaphylactic reaction to peanuts, and even a small amount of food can trigger a reaction. Other symptoms include headache, stomach pain, swelling, itching and sneezing. Some allergies can be treated with an over-the-counter antihistamine, while others require a self-injected shot of epinephrine. The eight most common food allergens include peanuts, tree nuts, wheat, eggs, shell fish, fish, dairy and soy. Strict avoidance of the known allergen is recommended.


Although food sensitivities can have the same symptoms as food allergies—digestive reactions, sinus troubles, muscle pain, headaches, rashes—they also include brain fog, sleep disturbances and urinary issues, and can also play a role in fertility. Food sensitivity reactions are not life-threatening, but do contribute to the chronic complaints of many people. Both irritable bowel syndrome (IBS) and migraines are linked to food sensitivities and show tremendous resolution when the dietary culprits are identified and the proper nutrition program is followed, which allows the body’s inflammation to subside and symptoms to abate. The onset of symptoms is often delayed, appearing as little as a few hours to as much as 72 hours after consumption of a trigger food. Unlike a food allergy, food sensitivities are not an immune reaction. The cell responds to the trigger food by producing mediators, like histamine, which cause the symptoms. Some food sensitivities are dose-related, meaning you might be able to have a small amount of the food before a reaction is triggered.


More common than food allergies are food intolerances, the most well-known of which is lactose intolerance. Marked by digestive symptoms, such as gas, bloating and diarrhea, lactose intolerance is caused by the lack of the enzyme lactase, which is necessary for the body to digest lactose, the sugar found in dairy products. Some individuals with lactose intolerance may be able to tolerate a small amount of dairy products or only certain forms of dairy without experiencing any symptoms. Lactose-free dairy products are available, and lactase supplements, if taken before eating a dairy product, can help reduce or eliminate any symptoms.

If you suffer from digestive woes, sinus congestion, skin rashes, migraines, brain fog or muscle and joint pain, it could be caused by one or more foods that you are eating. Even perfectly healthy foods can potentially be the culprit for the inflammation that’s at the root of your symptoms. A physician or registered dietitian nutritionist who specializes in food allergies and sensitivities can help you figure out your trigger foods and craft the appropriate food plan to help heal your body.

U Rock Girl!U Rock Girl! Contributor

Tiffani Bachus, R.D.N., and Erin Macdonald, R.D.N., are the co-founders of U Rock Girl!, a website designed to nourish the mind, body and spirit of women of all ages and stages of life. They have just authored the rockin' breakfast cookbook, No Excuses! 50 Healthy Ways to ROCK Breakfast! available at

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