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  • Writer's pictureChristina Seibold

Food Allergy vs. Sensitivity: Understanding the Difference & How to Test

By Christina Seibold, MS, CNS

In today's world, an increasing number of individuals are experiencing adverse reactions to certain foods. It is crucial to distinguish between food allergies and food sensitivities, as they are distinct conditions with varying symptoms and underlying mechanisms [1]. In this blog post, we will explore the differences between food allergies and food sensitivities, discuss how to test for food allergies, highlight common signs and symptoms associated with each, and discuss reasons why food allergies and food sensitivities are more common now than they were 15-20 years ago.

Food Allergies

A food allergy is an immune-mediated response triggered by the ingestion of specific foods. In individuals with food allergies, the immune system mistakenly identifies harmless proteins in certain foods as threats, leading to an exaggerated immune response [1]. Common reactions to food allergies can range from mild to severe and may include:

  1. Skin reactions: Itchy skin, hives, eczema, or swelling of the skin.

  2. Gastrointestinal symptoms: Nausea, vomiting, abdominal pain, or diarrhea.

  3. Respiratory issues: Wheezing, coughing, shortness of breath, or nasal congestion.

  4. Cardiovascular symptoms: Rapid heartbeat, low blood pressure, or fainting.

  5. Anaphylaxis: A severe and potentially life-threatening reaction characterized by a sudden drop in blood pressure, difficulty breathing, and swelling of the throat.

Common Food Allergens

Food allergies can be triggered by various substances, but there are 12 foods that are responsible for the majority of allergic reactions.

  1. Eggs

  2. Fish

  3. Shellfish

  4. Tree nuts (e.g., almonds, walnuts)

  5. Peanuts

  6. Wheat

  7. Soy

  8. Milk

  9. Sesame seeds

  10. Mustard

  11. Celery

  12. Lupin

Testing for Food Allergies

To diagnose a food allergy, medical professionals employ different methods, including:

  1. Skin prick test: A small amount of allergenic extract is placed on the skin, followed by a gentle prick. The appearance of a raised, red bump within 15-20 minutes indicates a positive reaction [3].

  2. Blood tests: Specific IgE blood tests measure the presence of allergen-specific antibodies in the blood. These tests include the ImmunoCAP test and the RAST test [2].

  3. Oral Food Challenge: Under medical supervision, the individual consumes small amounts of the suspected allergen to monitor any adverse reactions.

Food Sensitivities

Unlike food allergies, food sensitivities do not involve the immune system's immediate response. Instead, food sensitivities are characterized by a delayed reaction to certain foods, often involving the digestive system. Common symptoms of food sensitivities may include [4]:

  1. Digestive issues: Bloating, gas, abdominal pain, or diarrhea.

  2. Skin conditions: Eczema, rashes, or acne.

  3. Migraines or headaches.

  4. Fatigue or lethargy.

  5. Joint pain or inflammation.

Common Food Sensitivities

While food sensitivities can vary from person to person, some foods are more commonly associated with triggering sensitivities. The following 10 foods are often reported as common sensitivities:

  1. Gluten-containing grains (e.g., wheat, barley, rye)

  2. Dairy products

  3. Eggs

  4. Soy

  5. Corn

  6. Citrus fruits

  7. Nightshade vegetables (e.g., tomatoes, eggplants)

  8. Shellfish

  9. Artificial food additives (e.g., food coloring, preservatives)

  10. Histamine-rich foods (e.g., fermented foods, aged cheeses) [4,5]

Testing for Food Sensitivities

Identifying food sensitivities can be challenging since symptoms can manifest hours or even days after consuming the offending food. Several testing methods are available, including:

  1. Elimination diet: This involves removing suspected trigger foods from the diet for a specified period, followed by reintroducing them individually to observe any reactions [4].

  2. IgG blood tests: These tests measure the levels of IgG antibodies associated with specific foods, indicating potential sensitivities. However, the scientific community debates their reliability and clinical significance [4].

  3. Food Diary: Keep a detailed record of your meals and symptoms to identify patterns and potential trigger foods.

So why are we seeing more food allergies and food sensitivities than previous generations?

The increase in the prevalence of food allergies and sensitivities over the past 15-20 years can be attributed to several factors. While the exact reasons are still being studied and understood, researchers have proposed several potential explanations for this phenomenon:

  1. Hygiene Hypothesis: The hygiene hypothesis suggests that reduced exposure to certain microorganisms early in life due to improved hygiene practices and reduced rates of infections may lead to an overactive immune system, increasing the risk of developing allergies and sensitivities [6]. The lack of early microbial diversity and stimulation of the immune system may contribute to immune dysregulation and an increased susceptibility to allergic reactions.

  2. Environmental Factors: Environmental factors, such as pollution and exposure to allergens, may play a role in the development of food allergies and sensitivities. Air pollution and environmental pollutants can exacerbate respiratory allergies and contribute to the overall burden on the immune system, potentially increasing the risk of food allergies [7].

  3. Dietary Changes: Changes in dietary patterns, including an increased consumption of processed foods, additives, and preservatives, have been suggested as a contributing factor to the rising prevalence of food allergies and sensitivities. The Western diet, characterized by high-fat, high-sugar, and low-fiber intake, has been associated with alterations in the gut microbiome, inflammation, and increased susceptibility to allergies [8].

  4. Early Introduction of Allergenic Foods: Traditionally, allergenic foods were delayed in the introduction to infants' diets as a precautionary measure. However, recent research has suggested that early introduction of allergenic foods, such as peanuts and eggs, may actually reduce the risk of developing allergies. Delayed introduction and avoidance of allergenic foods may lead to an increased risk of sensitization and subsequent allergies [9].

  5. Genetic Predisposition: Genetic factors contribute to an individual's susceptibility to food allergies and sensitivities. Certain genetic variations and family history of allergic conditions can increase the likelihood of developing allergies [5]. However, changes in the prevalence over a relatively short time period suggest that genetic factors alone cannot fully explain the observed increase.

It is important to note that while these factors provide potential explanations for the increased prevalence of food allergies and sensitivities, further research is needed to fully understand the complex interplay of these factors and their impact on the rising incidence of these conditions.

Understanding the distinctions between food allergies and food sensitivities is crucial for individuals who experience adverse reactions to certain foods. While food allergies involve an immediate immune response and can cause severe reactions, food sensitivities typically involve delayed symptoms and primarily affect the digestive system. Identifying and managing these conditions require appropriate testing methods, such as skin prick tests and blood tests for allergies, and elimination diets for sensitivities. If you suspect you have a food allergy or sensitivity, consulting with a healthcare professional is essential for an accurate diagnosis and appropriate management.


[1] S. H. Sicherer and H. A. Sampson, "Food allergy: Epidemiology, pathogenesis, diagnosis, and treatment," J Allergy Clin Immunol, vol. 133, no. 2, pp. 291-307, 2014.

[2] J. A. Boyce et al., "Guidelines for the diagnosis and management of food allergy in the United States: Report of the NIAID-sponsored expert panel," J Allergy Clin Immunol, vol. 126, no. 6 Suppl, pp. S1-S58, 2010.

[3] I. J. Skypala et al., "Development and validation of a structured questionnaire for the diagnosis of Oral Allergy Syndrome in subjects with seasonal allergic rhinitis during the UK birch pollen season," Clin Exp Allergy, vol. 41, no. 6, pp. 1001-1011, 2011.

[4] I. Aziz, M. Hadjivassiliou, and D. S. Sanders, "The spectrum of noncoeliac gluten sensitivity," Nat Rev Gastroenterol Hepatol, vol. 12, no. 9, pp. 516-526, 2015.

[5] I. Pali-Schöll and E. Jensen-Jarolim, "Anti-acid medication as a risk factor for food allergy," Allergy, vol. 66, no. 4, pp. 469-477, 2011.

[6] R. J. Bertelsen et al., "The Hygiene Hypothesis in the Development of Allergic and Autoimmune Diseases—A Systematic Review," Pediatr Allergy Immunol Pulmonol, vol. 32, no. 2, pp. 55-68, 2019.

[7] A. J. Liu et al., "Air Pollution and Allergic Diseases: A Paradigm Shift," Int Immunol, vol. 31, no. 3, pp. 139-149, 2019.

[8] S. Venter et al., "Dietary Interventions for Allergy Prevention in Infants: Systematic Review and Meta-analysis," J Allergy Clin Immunol, vol. 141, no. 2, pp. 507-516.e6, 2018.

[9] K. C. Nwaru et al., "Timing of Allergenic Food Introduction to the Infant Diet and Risk of Allergic or Autoimmune Disease: A Systematic Review and Meta-analysis," JAMA, vol. 316, no. 11, pp. 1181-1192, 2016.

[10] K. M. Gieras et al., "Genetic Factors in Food Allergy," Current Opinion Allergy Clin Immunol, vol. 15, no. 3, pp. 211-216,015.

Disclaimer: Information in this article is for educational or information purposes only and should not be considered a substitute for professional medical advice or consultation with healthcare professionals. Elevate Functional Nutrition LLC does not offer medical advice and assumes no responsibility or liability for the information contained in this post. Always consult a medical professional or other qualified health care provider for medical advice, diagnoses, or treatment.


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