Explore the differences between food sensitivities and allergies, their symptoms, and how they may relate to autoimmune diseases. Learn how to identify triggers and manage your diet for better health.

This month, we are spotlighting autoimmune diseases, a group of more than 80 chronic conditions in which the immune system—meant to defend us—mistakenly attacks the body’s own tissues. From rheumatoid arthritis and Hashimoto’s thyroiditis to celiac disease and lupus, these conditions affect millions and can show up in unexpected ways—through fatigue, joint pain, digestive issues, skin changes, or brain fog.

Autoimmune conditions are highly individual, but one common thread that I’ve noticed in the patients who work with me is being nervous about eating certain foods they believe they are sensitive to for fear of symptom flares and decreased quality of life. While no single diet or lifestyle change can cure autoimmune conditions, everyday choices can make a powerful difference. By calming the body’s stress response, supporting gut health, nourishing with anti-inflammatory foods, and prioritizing rest and recovery, we can help create an environment in which the immune system functions more smoothly.

What Are Food Sensitivities?

Food sensitivities, often referred to as non-allergic food hypersensitivities, occur when certain foods trigger a negative response in the body, but not through the immune system as in allergies. Symptoms can be diverse and may include gastrointestinal issues like bloating, gas, or diarrhea, as well as headaches, fatigue, and mood disturbances. These reactions are typically dose-dependent (think portion sizes) and may not occur unless a significant amount of the offending food is consumed. Unlike food allergies, which involve an immediate immune response, food sensitivities can be delayed, making them harder to identify.

Food Sensitivities vs. Food Allergies

As I tend to note when in patient sessions or with my students in my nutrition science classes, an allergic reaction is generally toward the proteins found in food whereas intolerances/sensitivities are more related to the digestion of carbohydrates, which is why you’ll see an allergy reaction take place more so in the upper respiratory or gastrointestinal tract (think swollen lips, difficulty breathing or swallowing) versus in the lower gut. Common culprits include non-gluten wheat intolerance, dairy (lactose intolerance), and certain food additives.

The main distinctions between food sensitivities and food allergies are:

• Immune Response: Food allergies involve the immune system, specifically immunoglobulin E (IgE) antibodies, leading to immediate reactions. Food sensitivities do not involve IgE antibodies and are not immune-mediated [1].
• Severity: Allergic reactions can be severe and life-threatening, including symptoms like hives, swelling, and anaphylaxis. Sensitivities are generally less severe but can still significantly impact quality of life.
• Onset of Symptoms: Allergy symptoms typically occur within minutes to a few hours after exposure. Sensitivity symptoms may be delayed, appearing several hours to days later.
• Diagnosis: Allergies can often be diagnosed through skin prick tests or blood tests measuring specific IgE antibodies. Diagnosing sensitivities is more complex and may involve elimination diets and food diaries.

Learn more about the critical differences between food allergies and intolerances in our webinar recording below:

The Link Between Food Sensitivities and Autoimmune Conditions

Emerging studies suggest that food sensitivities may play a role in the development or exacerbation of autoimmune diseases. In fact, one of my favorite topics to discuss with my undergrads in our Life Cycle Nutrition course is something called the Hygiene Hypothesis, which states that early introduction to pathogens can strengthen the immune system where reduced exposure to microbes may lead to a weaker immune system, increasing the risk of allergies and autoimmune diseases [2].

Autoimmune conditions occur when the immune system mistakenly attacks the body’s own tissues. Chronic inflammation, often associated with food sensitivities, is a common feature in autoimmune diseases like celiac disease, rheumatoid arthritis, and lupus.

For instance, in celiac disease, an autoimmune response is triggered by gluten, leading to damage in the small intestine. In the case of lactose intolerance, the body is sensitive to lactose, the naturally occurring sugar found in milk or dairy products. The damage factor is much less, but the pain or discomfort someone may experience is just as serious. While not all food sensitivities lead to autoimmune diseases, they can contribute to systemic inflammation, potentially aggravating existing conditions.

Identifying and Managing Food Sensitivities

If you suspect you have a food sensitivity, consider the following steps:

1. Keep a Food Diary: Document what you eat and any symptoms that follow. This can help identify patterns and potential triggers.
2. Elimination Diet: Under the guidance of a healthcare professional, remove suspected foods from your diet for a period (usually 2-3 weeks), then gradually reintroduce them to observe any reactions [3].
3. Consult a Professional: Work with a registered dietitian (like me!) or healthcare specialist like an immunologist or gastroenterologist to ensure nutritional adequacy and to interpret your findings accurately.
4. Consider Testing: While there are no definitive tests for food sensitivities, some practitioners may use certain assessments to guide dietary recommendations. It is here where I would advise against at-home or self-tests since most have been found to be inadequate or giving mostly false-positive or false-negative results [4,5]. According to the NIH, it is also “impossible to find out standards and regulations” of these products, especially if you are purchasing them over the Internet [6].

Common Food Sensitivities

Some of the most frequently reported food sensitivities include:

1. Lactose, the naturally occurring carbohydrate (sugar) found in milk and dairy products
2. Caffeine
3. Salicylates, a chemical compound found in aspirin, but also naturally present in legumes (e.g., lentils, beans), vegetables (e.g., cauliflowers, pickled vegetables), fruits (e.g., strawberries, plums, watermelons, raspberries), some cereals (e.g., buckwheat, oat or corn), and herbs and spices
4. Amines (histamine), a chemical compound found in so many food items and processed foods like cheese, chocolate, pickled or smoked meat and fish products, wines, yeast extracts, and some fruits and vegetables (e.g. citrus, tomato, avocado, banana).
5. FODMAPs which stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. This most common protocol in managing IBS is following a low-FODMAP approach, administered by a Registered Dietitian or well trained healthcare professional.
6. Sulfites, which are used as preservative and found in beer, wine, lemon juice, molasses, sauerkraut, gravies and sauces, soft drinks, fruit juices; shrimp, lobster and other crustaceans; dough foods like biscuits, pie and pizza crusts.
7. Sugar substitutes used by many who are following a low-calorie or sugar-free diet. The three categories are artificial sweeteners (also called nonnutritive sweeteners), sugar alcohols and novel sweeteners, most of which are created from synthetic or natural chemicals in a lab. Some examples are aspartame (brand names include Nutrasweet®, Equal®, and Sugar Twin®), saccharin (brand names include Sweet and Low®, Sweet Twin®, Sweet’N Low®, and Necta Sweet®), and sucralose (brand name Splenda®).

Actionable Immune-Supporting Habits

Understanding the nuances between food sensitivities and allergies is vital for managing your health effectively. While sensitivities are less severe than allergies, they can still significantly impact well-being and may be linked to autoimmune conditions. By identifying and managing food sensitivities through careful observation and professional guidance, you can take proactive steps toward better health and improved quality of life.

Consider the below, regardless if you’re managing an autoimmune disease, chronic condition, or not:

• Eat the rainbow: Aim for a variety of colorful vegetables and fruits to load up on healthful properties like phytochemicals and antioxidants, those naturally occurring compounds that protect our cells. Click here for easy and affordable ideas on how to incorporate these foods into your weekly meal plan.
• Prioritize sleep: Shoot for 7–9 hours of high-quality rest to support immune repair and hormone balance. Create a bedtime routine to help you wind down, turn off screens, and prepare for the next day so that you can focus on drifting off to la-la land.
• Move regularly, gently: Daily movement like walking, stretching, or yoga helps reduce inflammation without overtaxing the body.
• Limit ultra-processed foods: These can drive inflammation and disrupt the gut microbiome—opt for whole, minimally processed meals when possible.
• Practice stress reduction: Even 5–10 minutes a day of deep breathing, journaling, or mindfulness can calm immune overactivity. Check out our top tips to managing stress and incorporating mindful habits.
• Stay hydrated: Proper hydration helps transport nutrients and flush out toxins that may otherwise aggravate inflammation. Not a fan of plain water? Experiment with flavored seltzers or herbal teas instead. On hot or high-intensity workout days especially, find ways to get fluids into your body.

Navigating the complex world of food reactions can be challenging. Many individuals experience discomfort after eating certain foods, but distinguishing between a food allergy, intolerance, or sensitivity can help better customize effective management and overall health.

References:

1. Li, J. (2024, February 28). Food allergy vs. food intolerance: What’s the difference? Mayo Clinic. https://www.mayoclinic.org/diseases-conditions/food-allergy/expert-answers/food-allergy/faq-20058538
2. ‌Okada, H., Kuhn, C., Feillet, H., & Bach, J.-F. . (2010). The “hygiene hypothesis” for autoimmune and allergic diseases: an update. Clinical & Experimental Immunology, 160(1), 1–9. https://doi.org/10.1111/j.1365-2249.2010.04139.x
3. Malone, J. C., & Daley, S. F. (2024). Elimination Diets. PubMed; StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK599543/
4. The myth of IgG food panel testing | AAAAI. (2012). Aaaai.org. https://www.aaaai.org/tools-for-the-public/conditions-library/allergies/igg-food-test
5. ‌Are Food Sensitivity Tests Accurate? (n.d.). Www.eatright.org. https://www.eatright.org/health/health-conditions/allergies-and-intolerances/are-food-sensitivity-tests-accurate
6. Tidy, E. J., Shine, B., Oke, J., & Hayward, G. (2018). Home self-testing kits: helpful or harmful? British Journal of General Practice, 68(673), 360–361. https://doi.org/10.3399/bjgp18x698021