Nutrition is a fundamental aspect of our health and well-being. Food provides us with the energy and nutrients our bodies need to function properly. However, for some people, certain foods can trigger adverse reactions.

These reactions can be classified as either food allergies or food intolerances/sensitivities. While both conditions involve an abnormal response to food, they are distinct in their causes, symptoms, and treatments.

This article will explore the differences between nutrition allergy and intolerance/sensitivity to help you understand what may be causing your food-related symptoms.

What is Nutrition Allergy?

A nutrition allergy is a severe immune-mediated response to certain foods or food components.

When a person with a food allergy ingests the allergen (the substance that triggers the allergic reaction), their immune system perceives it as a threat and overreacts, producing an inflammatory response that can affect different body organs or systems. The symptoms of a nutrition allergy can range from mild to severe and may include:.

Hives and itching
Skin rash
Nausea and vomiting
Diarrhea
Abdominal cramps
Swelling of the lips, tongue, and throat
Difficulty breathing
Anaphylaxis (a severe and life-threatening allergic reaction that can cause shock and circulatory collapse)

The most common allergenic foods are peanuts, tree nuts, fish, shellfish, eggs, milk, soy, and wheat. However, people can be allergic to any food, including fruits, vegetables, and spices.

Food allergy affects about 8% of children and 4% of adults in the United States, according to the Centers for Disease Control and Prevention (CDC).

What is Nutrition Intolerance/Sensitivity?

A nutrition intolerance/sensitivity is a non-immune-mediated adverse reaction to certain foods or food components that does not involve the immune system.

The most common types of nutrition intolerance/sensitivity are lactose intolerance (difficulty digesting lactose, the sugar in milk), gluten intolerance (celiac disease, a genetic autoimmune disorder that damages the small intestine), and sensitivity to food additives such as monosodium glutamate (MSG) and sulfites.

The symptoms of nutrition intolerance/sensitivity can be similar to those of nutrition allergy, but usually less severe and not life-threatening. Some common symptoms of nutrition intolerance/sensitivity include:.

Abdominal pain and discomfort
Bloating and gas
Diarrhea
Constipation
Headaches
Fatigue
Brain fog
Joint pain
Depression and anxiety

The prevalence of nutrition intolerance/sensitivity is not well-established, but estimated to be much higher than that of nutrition allergy.

For example, lactose intolerance affects up to 75% of the world’s population, according to the National Institutes of Health (NIH).

What Causes Nutrition Allergy and Intolerance/Sensitivity?

Nutrition allergy and intolerance/sensitivity have different underlying causes and mechanisms.

Nutrition allergy is caused by an abnormal immune response to allergenic proteins in food that triggers the production of antibodies (IgE) against the allergen.

When the person is exposed to the same allergen again, the antibodies signal the immune system to release chemicals such as histamine, which cause the characteristic symptoms of an allergic reaction.

Nutrition intolerance/sensitivity, on the other hand, is caused by the inability or reduced ability of the body to digest or metabolize certain foods or food components, or by the direct toxic effect of food additives. For example:.

Lactose intolerance is caused by the deficiency or reduction of lactase, the enzyme that breaks down lactose into glucose and galactose. When lactose passes undigested into the colon, it can ferment and cause gas, bloating, and diarrhea. Lactose intolerance is more common in people of African, Asian, Hispanic, and Native American descent than in people of European descent, according to the NIH.
Celiac disease is caused by an abnormal immune response to gluten, a protein found in wheat, barley, and rye. The immune system attacks the lining of the small intestine, leading to nutrient malabsorption and a range of symptoms such as diarrhea, weight loss, anemia, and osteoporosis. Celiac disease is estimated to affect about 1% of the population worldwide, according to the Celiac Disease Foundation.
Sensitivity to food additives such as MSG and sulfites is not well-understood, but may involve the direct activation of certain nerves or chemicals in the body that cause symptoms such as headache, flushing, and wheezing. Sensitivity to food additives is not an immune-mediated reaction.

How are Nutrition Allergy and Intolerance/Sensitivity Diagnosed?

The diagnosis of nutrition allergy and intolerance/sensitivity requires a medical evaluation by a healthcare professional specialized in these conditions, such as an allergist or gastroenterologist. The diagnostic process involves:.

A detailed medical history, including the type, severity, and timing of symptoms after food exposure, and any family history of food-related conditions
A physical examination, including allergy skin testing, blood tests, and/or endoscopy
An elimination diet and food diary, in which the person avoids suspected trigger foods for a certain period and then reintroduces them one by one to see if the symptoms recur

It is important not to self-diagnose or self-treat a possible nutrition allergy or intolerance/sensitivity based on unreliable sources of information or assumptions.

Undiagnosed and untreated nutrition allergy or intolerance/sensitivity can lead to serious health complications, including anaphylaxis, malnutrition, and chronic inflammation.

How are Nutrition Allergy and Intolerance/Sensitivity Treated?

The treatment of nutrition allergy and intolerance/sensitivity depends on the severity and type of the condition, as well as the individual’s age, overall health, and lifestyle habits.

Nutrition allergy is usually treated with avoidance of the allergen, which requires careful reading of food labels, restaurant menus, and ingredient lists.

In case of accidental exposure to the allergen, the person may need to use self-injectable epinephrine (such as an EpiPen) and seek emergency medical assistance. Some cases of nutrition allergy may also benefit from immunotherapy, which involves gradually exposing the person to increasing doses of the allergen under medical supervision to desensitize their immune system.

Nutrition intolerance/sensitivity is typically treated with dietary modifications, such as avoiding or reducing the intake of the trigger foods or using substitutes, supplements, or enzymes that aid digestion. For example:.

Lactose intolerance can be managed by consuming lactose-free dairy products or taking lactase supplements before eating lactose-containing foods.
Celiac disease requires a strict gluten-free diet that excludes wheat, barley, rye, and any products that contain them. Some celiac patients may also need to take vitamin and mineral supplements to correct nutrient deficiencies.
Sensitivity to food additives may improve by avoiding or reducing the intake of the offending additives and choosing natural or unprocessed foods.

In some cases, nutrition intolerance/sensitivity may resolve or improve spontaneously over time, especially if the underlying cause is related to a temporary digestive problem.

Conclusion

Nutrition allergy and intolerance/sensitivity are common yet complex conditions that require a thorough understanding of their causes, symptoms, and treatments.

If you suspect that you may have a food-related problem, seek medical advice from a qualified healthcare provider who can help you diagnose and manage your condition. Remember that nutrition is a key factor in your health and wellness, and that a balanced and varied diet can provide you with all the nutrients you need without compromising your enjoyment of food.