In recent years, discussions regarding food sensitivities and food allergies have become increasingly prevalent. However, many individuals are not always aware of the differences between a food allergy and a food sensitivity. While the terms are often used interchangeably, they refer to distinct conditions, characterised by unique mechanisms and symptoms. Understanding these differences is essential for proper management and treatment, allowing people to make informed dietary choices.
WHAT IS A FOOD ALLERGY?
A food allergy occurs when the body’s immune system identifies a harmless food or ingredient as a threat, therefore triggering an immune response. This response generally involves the production of an antibody called Immunoglobulin E (IgE), which plays a key role in allergic reactions.
1. Introduction To Immunity
The immune system is the body’s primary defense mechanism, protecting us against harmful invaders, such as bacteria, viruses, and toxins. The immune system uses special tools, such as antibodies, and immune cells, to help identify and neutralize these invading pathogens, therefore protecting us from illness. One of these antibodies is Immunoglobulin E (IgE), which plays a key role in allergic reactions. When a person with a food allergy consumes or comes into contact with a specific food allergen, their immune system produces IgE antibodies. These antibodies trigger a cascade of immune responses, leading to the symptoms associated with an allergic reaction.
2. Types of Food Allergies
Understanding the mechanism of action for the different types of allergic reactions is essential for managing symptoms effectively. Food allergies can be categorized into three main types: IgE-mediated, non-IgE-mediated, and mixed reactions.
The most common type of food allergy is an IgE-mediated food allergy. In these reactions, the immune system mistakenly identifies certain foods or ingredients that are generally harmless to most people, as being dangerous or harmful, thus eliciting an immune response. This misidentification of the food by the IgE antibodies triggers the release of a chemical called histamine, which causes symptoms like swelling, hives, or difficulty breathing. IgE-mediated symptoms generally occur within minutes to hours after exposure to the allergen, making these reactions very rapid and potentially life-threatening in severe cases. The most common foods that cause IgE-mediated allergic responses are:
Peanuts
Tree nuts (like almonds or walnuts)
Shellfish (like shrimps or lobster)
Fish
Milk
Eggs
Wheat
Soy
Unlike IgE-mediated allergies, non-IgE-mediated food allergies involve other parts of the immune system and do not rely on IgE antibodies in their defence mechanism. These reactions are often delayed, with symptoms appearing hours or even days after exposure to the allergen. Symptoms are usually gastrointestinal-related and include symptoms like diarrhoea, constipation and reflux. The most common non-IgE-mediated food allergies are:
Food protein-induced enterocolitis syndrome (FPIES)
Eosinophilic oesophagitis (EoE)
Some allergic reactions involve both IgE and non-IgE mechanisms. These mixed reactions combine features of both types and can affect multiple systems in the body. A common example is atopic dermatitis. Individuals with atopic dermatitis struggle with chronic skin inflammation, eczema, itching and flare-ups, which are linked to specific dietary triggers.
3. Signs and Symptoms
Food allergies trigger an immune response that results in symptoms ranging from mild discomfort to severe, life-threatening reactions. Recognizing these symptoms is crucial for timely intervention and effective management.
The symptoms of a food allergy typically occur shortly after exposure to an allergen and may affect the skin, gastrointestinal system, respiratory system, or cardiovascular system. Common signs include:
Red, itchy welts on the skin, hives or rashes
Swelling (particularly of the tongue, lips, face, or throat, which can impair breathing or swallowing)
Respiratory issues like wheezing, coughing, or difficulty breathing
Gastrointestinal distress like stomach pain, vomiting, and diarrhoea
In severe cases, a food allergy can lead to anaphylaxis, a rapid and potentially life-threatening reaction. Common signs of anaphylaxis include:
Severe swelling of the throat, leading to airway obstruction
Difficulty breathing or shortness of breath
A sudden drop in blood pressure, which may cause dizziness, fainting, or shock
Rapid or weak pulse
Loss of consciousness
Anaphylaxis is a medical emergency that requires immediate treatment with epinephrine (e.g., an EpiPen) and urgent medical attention.
4. Diagnosing Food Allergies
Accurately diagnosing food allergies is essential for effective management and involves a combination of medical history, physical examination, and diagnostic tests. The most common diagnostic tests include Skin Prick Tests, IgE Blood Tests and Oral Food Challenges.
The oral food challenge is considered the most accurate method for diagnosing food allergies and is the gold standard for allergy diagnosis. This method needs to be conducted under strict medical supervision. This method involves gradually consuming increasing amounts of the suspected allergen while monitoring for any signs of an allergic reaction. Although highly reliable, the oral food challenge is time-consuming and requires specialised medical personnel due to the potential risk of severe allergic reactions, such as anaphylaxis. For this reason, it is mostly used when other tests yield inconclusive results or when the diagnosis needs confirmation.
The skin prick test is one of the most common and widely used diagnostic methods. With a skin prick test, a small drop of the allergen extract (i.e. peanut extract) is placed on the skin (usually on the forearm or the back). The skin is gently pricked, allowing the allergen extract to penetrate the skin’s surface. If the individual is allergic to the substance, a raised, red bump (called a wheal) will appear within 15 to 20 minutes. This test is quick, minimally invasive, and provides immediate results, however, it is not always conclusive and may need to be complemented with other diagnostic tools.
The last diagnostic tool is the IgE blood test, which measures the level of immunoglobulin E (IgE) antibodies in the blood in response to specific allergens. This test is particularly useful for individuals who cannot undergo skin prick testing due to skin conditions or other contraindications. While IgE blood tests are convenient, they can sometimes produce false-positive results, therefore, the results should always be interpreted alongside a detailed medical history and other diagnostic tools.
5. Managing Food Allergies
The most effective way to manage a food allergy is to completely avoid the allergen. It is essential to read food labels carefully, checking the ingredient list thoroughly and learning that allergens may also go by different names (i.e. casein for milk). Many food packages also include statements such as “may contain” or “produced in a facility that processes”. These warning labels can also help you make informed decisions about potential cross-contamination risks.
Having a contingency plan is crucial as even with the best precautionary measures, accidental exposures may still happen. Work with your healthcare provider to develop an action plan for managing allergic reactions, including when and how to use emergency medication like an EpiPen (epinephrine auto-injector pen). It is essential to share your plan with those around you, such as family, friends, teachers, and coworkers to ensure they know how to respond in case of an emergency. Always carry an EpiPen with you and make sure to check that it is not expired.
Education and awareness are also vital for creating a supportive environment. Train others on how to use the EpiPen, inform them of your allergy, and educate them on symptoms to watch out for. Managing food allergies involves more than just avoiding trigger foods—it requires careful planning, communication, and education. By staying prepared, you can reduce the risk of exposure and ensure that you are ready to handle emergencies effectively.
WHAT IS A FOOD SENSITIVITY?
A food sensitivity, also known as a food intolerance, is a non-immune response to food that typically takes place in the digestive system. It occurs when the body is unable to break down a specific food or nutrient, often due to an enzyme deficiency, sensitivity to food additives or naturally occurring chemicals in food. Unlike food allergies, food sensitivities are not life-threatening but can still cause discomfort.
1. Signs and Symptoms
Symptoms of food sensitivities can vary. Symptoms are often dose-dependent and tend to worsen as the quantity of the trigger food increases. Common symptoms of food sensitivities include:
Gastrointestinal discomfort
Bloating
Stomach pain
Flatulence or gas
Diarrhoea
Vomiting and nausea
Heartburn or reflux
Skin flushing
Fatigue
2. Common Types of Food Sensitivities
Food sensitivities can arise from various triggers, ranging from specific nutrients to food additives or naturally occurring compounds. The two most common types of food sensitivities are: Lactose Intolerance and Gluten Intolerance (Non-Celiac Gluten Sensitivity).
Lactose intolerance is one of the most common food sensitivities. Lactose intolerance occurs when the body lacks lactase, the enzyme responsible for breaking down lactose, which is a sugar found in dairy products. This lactase deficiency leads to symptoms like bloating, gas, diarrhoea, and abdominal pain shortly after consuming lactose-containing products. The top sources of lactose include milk, yoghurt, cream and some processed foods.
Non-Celiac Gluten Sensitivity refers to a reaction to gluten that does not involve the autoimmune response seen in Celiac disease. Gluten is a protein that is found in wheat, barley and rye. Symptoms of gluten sensitivity may include bloating, diarrhoea, fatigue, and headaches after consuming gluten-containing foods. The top sources of gluten include pasta, bread, cereals and baked goods made with wheat, rye or barley.
In addition to lactose and gluten sensitivities, many people may experience reactions to other foods or ingredients, such as food additives (like sulphites, monosodium glutamate (MSG) and artificial sweeteners); histamine (which is often found in foods like aged cheeses, fermented foods and alcohol); and fructose (which is generally found in foods like apples, pears, honey and cold drinks).
3. Diagnosing Food Sensitivities
Diagnosing food sensitivities can be challenging as symptoms often overlap with other conditions. The most common diagnostic tool is elimination diets, where the suspected trigger foods are removed from the diet for a period of time and then reintroduced one at a time to observe for reactions. This should be done with the guidance of a Dietitian; whereas food trials with patients will allergies, should be done strict medical supervision as previously mentioned (i.e.: with an Allergist). A food diary is essential for this method to track the foods consumed and the symptoms experienced to identify any patterns and potential triggers.
Medical tests can be done, although not as common. Blood tests can be conducted for food sensitivities whereby the body's immune response to certain foods is measured by testing the levels of certain antibodies in the blood. These tests are however not very reliable and there is limited evidence to support the use of food sensitivity tests. Please consult with your healthcare provider to determine the best diagnostic approach tailored to your specific needs.
4. Managing Food Sensitivities
While food sensitivities may not be life-threatening, they can significantly impact quality of life if not managed properly. A thoughtful and informed approach can help reduce symptoms and allow individuals to maintain a balanced diet.
The first step in managing food sensitivities is to identify which foods or ingredients are contributing to your symptoms. Similarly to diagnostic methods, keeping a food diary can help you track your meals, and any symptoms experienced, allowing you to identify patterns and pinpoint specific triggers. Registered Dietitians can play a key role in this process. Dietitians help guide you in identifying problem foods without overly restricting your diet, ensuring you still meet your nutritional needs. One common method dietitians use is an elimination diet, where suspected trigger foods are temporarily removed and then systematically reintroduced, all while monitoring symptoms. This approach helps confirm sensitivities while maintaining dietary balance.
Once trigger foods are identified, dietary adjustments can be made to help reduce or eliminate symptoms. Limiting or even avoiding the problem/trigger food is key for the management of food sensitivities. Finding suitable alternatives can help you integrate these foods or food groups into your daily life to help maintain nutritional balance (for example using plant-based milk products or lactose-free dairy products for individuals with lactose intolerance). Monitoring portion sizes is also essential, as small amounts of the trigger food may actually be tolerable in some cases.
In some cases, supplementation can help manage food sensitivities. Always consult a healthcare professional, such as a dietitian or doctor, before starting any supplements. Digestive enzymes and probiotics are some of the top supplements to consider. Enzyme supplements or digestive aids like lactase, for example, can help those with lactose intolerance digest dairy products more comfortably and probiotics may support gut health and improve symptoms related to certain sensitivities.
Understanding whether you’re dealing with a food allergy, or sensitivity can significantly improve your quality of life. While food allergies require strict avoidance due to the possibility of severe reactions, food sensitivities more often require managing trigger foods to reduce symptoms. With the right approach, you can continue to enjoy food while safeguarding your health.
If you suspect a food allergy or sensitivity, it is important to seek guidance from a qualified healthcare professional. Registered Dietitians, allergists, and gastroenterologists can help identify triggers and develop a management plan tailored to your needs.
REFERENCES
1. American College of Allergy, Asthma & Immunology (n.d.) Food allergy testing and diagnosis. Available at: https://acaai.org/allergies/testing-diagnosis/food-allergy-testing-and-diagnosis/ (Accessed: 15 November 2024).
2. Latitude Food Allergy Care (n.d.) Food sensitivity vs. food allergy. Available at: https://latitudefoodallergycare.com/resources/food-sensitivity-food-allergy (Accessed: 23 November 2024).
3. National Institute of Allergy and Infectious Diseases (n.d.) Diagnosing food allergy. Available at: https://www.niaid.nih.gov/diseases-conditions/diagnosing-food-allergy#:~:text=The%20gold%20standard%20for%20diagnosing,known%20as%20a%20false%20positive (Accessed: 23 November 2024).
4. Sicherer, S.H. and Sampson, H.A. (2018) ‘Food allergy: A review and update on epidemiology, pathogenesis, diagnosis, prevention, and management’, Journal of Allergy and Clinical Immunology, 141(1), pp. 41–58. Available at: https://doi.org/10.1016/j.jaci.2017.11.003 (Accessed: 23 November 2024).
5. Tang, M.L.K. and Mullins, R.J. (2017) ‘Food allergy: Is prevalence increasing?’, Internal Medicine Journal, 47(3), pp. 256–261. Available at: https://doi.org/10.1111/imj.13362 (Accessed: 28 November 2024).
6. American Academy of Allergy, Asthma & Immunology (n.d.) Food intolerance. Available at: https://www.aaaai.org/tools-for-the-public/conditions-library/allergies/food-intolerance (Accessed: 28 November 2024).
Comments