Food allergy vs intolerance vs sensitivity: How to know the difference

The words used to describe unpleasant responses to certain foods, like food allergies, food intolerances and food sensitivities, are sometimes misinterpreted. 

For effective management and general well-being, it is essential to distinguish between these reactions because their symptoms, processes and intensity might vary.

Contrarily, food intolerances are non-immune reactions that frequently arise from the inability to digest particular chemicals, such as lactose or gluten properly. 

By deciphering the intricacies of these conditions, we hope to enable readers to make wise decisions and promote a better understanding of societal responses to food.

What are food allergies?

Allergies to some foods cause immune system reactions to particular proteins in those meals. 

These responses can be moderate, severe, or even potentially fatal in some circumstances. 

To correctly identify, treat, and prevent allergic triggers, it is imperative to comprehend the nature of food allergies.

Common food allergens

Top eight allergenic foods

The “big eight”—milk, eggs, peanuts, tree nuts, wheat, soy, fish and shellfish—are the most typical cause of food allergies

These items cause most food allergies, thus those with known sensitivities need to be constantly watched around them [1].

Top eight allergenic foods

While the “big eight” are more common, allergies can also arise to other foods, including sesame, mustard, celery and several fruits. Reading food labels carefully and being mindful of these less common allergies is crucial.

Cross-reactivity and hidden sources

When the proteins in two foods are identical, a condition known as cross-reactivity arises, which results in an allergic reaction to both foods. 

Furthermore, allergenic proteins might come from unexpected places, so it’s important to watch out for hidden allergens in processed foods and restaurant meals.

What are food intolerances?

When the body struggles to digest particular dietary ingredients, it can result in food intolerances, which are non-immune reactions. 

Contrary to immune-mediated food allergies, food intolerances are frequently caused by enzyme deficiency or digestive issues. 

For diagnosing symptoms, identifying trigger foods, and making suitable dietary adjustments, it is crucial to have a thorough understanding of food intolerances.

Food intolerances are adverse responses to particular meals or ingredients that do not involve the immune system. 

They result from the body’s inability to effectively digest or break down certain chemicals, such as lactose, gluten or dietary additives.

The lack of certain enzymes necessary for healthy digestion is the root cause of many food intolerances. For instance, a lack of the enzyme lactase, which breaks down lactose in milk and dairy products, results in lactose intolerance. 

Food intolerances can also be influenced by digestive illnesses like irritable bowel syndrome (IBS).

Common types of food intolerance

Lactose intolerance

The inability to digest lactose, a sugar in milk and dairy products, is known as lactose intolerance. Bloating, gas, stomach discomfort and diarrhea are possible symptoms.

Gluten intolerance (non-celiac gluten sensitivity)

When ingesting gluten-containing foods, people with non-celiac gluten sensitivity suffer symptoms resembling celiac disease. 

However, celiac disease does not include an immunological reaction or damage to the small intestine [2].

Fructose malabsorption

When the body has trouble absorbing fructose, a sugar present in fruits, honey and other sweeteners, it is said to have fructose malabsorption. Bloating, discomfort in the abdomen and diarrhea are possible symptoms.

Histamine intolerance

Being unable to effectively metabolize histamine, a substance naturally found in some meals, is defined by histamine intolerance. 

Symptoms including headaches, skin rashes, nasal congestion and gastrointestinal upset can be brought on by an excess of histamine.

What are food sensitivities?

A wide variety of negative responses to particular foods are included in food sensitivities. 

Contrary to food allergies, sensitivities may not trigger an immunological response, yet they nevertheless have the potential to cause uncomfortable symptoms. 

To identify hidden triggers, treat delayed onset symptoms, and make suitable dietary modifications, it is important to comprehend the nature of food sensitivities.

Identifying common triggers of food sensitivities

Gluten sensitivity

A negative reaction to meals containing gluten can occur in people who do not have celiac disease. 

This condition is referred to as gluten sensitivity or non-celiac gluten sensitivity. Gastrointestinal problems, exhaustion, headaches and joint discomfort are some of the symptoms.

Food chemical sensitivities

Some people could be hypersensitive to synthetic or naturally occurring chemicals in some meals. 

Histamine, sulfites, salicylates and food colorings are typical offenders. Different physiological systems may be affected and symptoms might vary greatly [3].

FODMAP sensitivity

A class of carbohydrates known as FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides and polyols) might make some people have digestive issues. Some fruits, vegetables, cereals and sweets are rich in FODMAPs.

Key differences: Allergies, intolerances, and sensitivities

For accurate detection, successful management, and suitable dietary changes, it is essential to understand the differences between food allergies, food intolerances and food sensitivities. 

While many of these disorders entail unfavorable responses to certain meals, important distinctions exist between them regarding their processes, reaction times, severity and diagnostic difficulties.

Contrasting mechanisms and immunological responses

Food allergies

Immunoglobulin E (IgE) antibodies affect the immune system’s reaction to allergies. When allergenic proteins are recognized by IgE antibodies, histamine and other substances are released [4].

The IgE-mediated immune response is also the primary immunological mechanism that underlies allergies.

Food intolerances

Intolerances often originate from problems digesting certain foods, including lactose or gluten, because of inadequate enzyme levels or digestive issues.

The immune system is also not involved in intolerances, and most of their underlying causes are not immunological.

Food sensitivities

Both immunological and non-immunological responses can be a part of sensitivities. 

Non-immunological sensitivities do not directly engage the immune system, whereas immunological sensitivities may include IgG antibodies or immune cells other than IgE.

Food sensitivities
Photograph: Prostock-studio/Envato

Time frame of reactions

Food allergies

A few minutes to a few hours after eating the allergenic meal, allergic symptoms often manifest.

Food intolerances

While signs of intolerance are frequently felt immediately, they can occasionally appear hours or even days later.

Food sensitivities

In most cases, symptoms of sensitivities develop hours or even days after taking the offending item.

Severity and potential risks

Food allergies

Mild to severe allergies are possible, and in rare cases, anaphylaxis, a potentially fatal condition, may develop.

If anaphylaxis is not treated quickly, it can be deadly and necessitates rapid medical assistance.

Food intolerances

While intolerances frequently result in gastrointestinal pain and symptoms, they do not immediately represent a risk to life.

Food sensitivities

Compared to allergies, sensitivities frequently cause fewer symptoms, yet they can still have a big influence on someone’s quality of life.

Role of genetics and environmental factors

Food allergies

Food allergies have a strong genetic component, with a higher risk if a family member has allergies.

Allergies can also arise due to environmental factors, such as early exposure to allergic foods.

Food intolerances

While certain intolerances, like lactose intolerance, may be influenced by heredity, environmental variables and acquired illnesses, like digestive problems, are frequently more important causes.

Food sensitivities

Uncertainty surrounds the connection between heredity and sensitivities, and several variables, such as immune system performance, gastrointestinal health and general vulnerability, might affect how sensitivities manifest.

Individuals and healthcare professionals can better manage the intricacies of food-related responses by being aware of these significant differences. 

Accurate diagnosis permits effective treatment techniques, such as dietary adjustments, avoidance tactics, and where necessary, expert advice. 

Understanding the differences between allergies, intolerances, and sensitivities encourages the development of a more thorough strategy for meeting individual dietary needs and enhancing general well-being.


A proactive strategy and individualized solutions are necessary for effectively treating food allergies, intolerances, and sensitivities. 

People may lessen symptoms, avoid problems, and maintain a well-balanced diet by practicing avoidance tactics, reading food labels attentively, changing their diets and getting expert advice. 

Knowing the differences between these illnesses, identifying trigger foods, and taking the proper precautions are essential to guarantee general well-being.

Individuals may negotiate their dietary constraints and have full lives with the right supervision.


How would you know a food allergy from a food intolerance?

An immune system reaction from a food allergy often produces acute symptoms and sometimes fatal consequences. A food intolerance, on the other hand, is a non-immune reaction that frequently results in delayed symptoms and predominantly affects digestion. 

What are 3 possible signs of a food allergy?

Immediate allergic responses, such as hives, swelling, or itching; respiratory symptoms, such as wheezing or trouble breathing; and gastrointestinal symptoms, such as nausea, vomiting, or diarrhea, are three potential food allergy indicators.

Can food intolerance go away?

Food intolerances are generally chronic conditions that do not go away entirely. However, the severity of symptoms can vary over time and may improve with dietary modifications, lifestyle changes, or other interventions.


The information included in this article is for informational purposes only. The purpose of this webpage is to promote broad consumer understanding and knowledge of various health topics. It is not intended to be a substitute for professional medical advice, diagnosis or treatment. Always seek the advice of your physician or other qualified health care provider with any questions you may have regarding a medical condition or treatment and before undertaking a new health care regimen, and never disregard professional medical advice or delay in seeking it because of something you have read on this website.