Food Allergies and Sensitivities – Symptoms, Detection, and Impact on the Body

Food Allergies and Sensitivities – Symptoms, Detection, and Impact on the Body

by , , | Feb 15, 2025

Approximately 33 million people in the United States have at least one food allergy. This includes nearly 11% of adults and about 8% of children. Food sensitivities, which are different from allergies, also affect a significant portion of the population, though exact numbers can vary. Food allergies and sensitivities have been on the rise in the United States over the past few decades. Here are some key statistics:

  1. Childhood Food Allergies: The prevalence of food allergies among children increased by 50% between 1997 and 2011. This trend continued, with another 50% increase between 2007 and 2021.
  2. Peanut and Tree Nut Allergies: The prevalence of self-reported peanut or tree nut allergies in children more than tripled between 1997 and 2008.
  3. Racial and Ethnic Disparities: The rate of increase in childhood food allergies has been faster among Black Americans (2.1% per decade) and Hispanic Americans (1.2% per decade) compared to White Americans (1% per decade)
  4. Multiple Food Allergies: About 40% of children with food allergies have multiple food allergies

Food sensitivities can vary widely in symptoms and severity. Here are some key trends and statistics on food sensitivities in the United States:

  1. Prevalence: It’s estimated that up to 20% of the population may have some form of food sensitivity. This includes sensitivities to common foods like lactose, gluten, and certain food additives.
  2. Lactose Intolerance: Approximately 36% of Americans have some degree of lactose intolerance. This condition is more prevalent among certain ethnic groups, including African Americans, Asian Americans, and Native Americans.
  3. Gluten Sensitivity: Non-celiac gluten sensitivity affects about 6% of the US population. This condition can cause symptoms similar to celiac disease but without the autoimmune response.
  4. Food Additives: Sensitivities to food additives, such as sulfites, MSG, and artificial colors, are also on the rise. These sensitivities can cause a range of symptoms, from headaches to digestive issues.
  5. Increase in Diagnoses: There has been a noticeable increase in the diagnosis of food sensitivities over the past decade, partly due to better awareness and improved diagnostic methods.

These statistics highlight the growing public health concern regarding food allergies and sensitivities in the US.

Perhaps you are one of those people diagnosed with a food allergy. If so, maybe you had one of those tests where they stuck needles coated with potential allergens into your back, and you itched like crazy with some of them. Those itchy ones were the food allergens. That itchiness is part of an IgE reaction, where the body identifies an allergen as an outside invader and directs the immune system to attack it. 

When you encounter an allergen, your immune system knows it and launches a reaction to defend you. First, it sends a chemical signal to “mast cells” in your skin, lungs, nose, mouth, gut, and blood. The message is, “Release histamines,” which are stored in the mast cells. This release of histamine is designed by the body to send a signal for how the immune system should react to an invader. The problem is its role in causing allergic and anaphylactic symptoms. When your body experiences a trigger to release histamine, it creates inflammation.  In some cases, your body can release excessive amounts of histamine or become unable to break down the histamine released. This can result in symptoms including flushing, hives, itchy skin, and difficulty breathing. That is a classic allergic reaction. In the case of food allergies, it means that when eating certain foods, or classes of foods, your body wrongly thinks that the food itself is harmful and triggers the body to attack it. The side effect of this action is the inflammation that causes swelling in the skin (hives, itchiness, and flushing) and swelling of the throat (difficulty breathing and dizziness). A severe allergic reaction can cause anaphylactic shock and death. Even mild reactions can be unpleasant, and can potentially worsen over time. 

The first time that you eat a food, you may not have an allergic reaction to that food, but over time that same food that once seemed “safe” may now trigger a reaction. Why is that? According to the American College of Allergy, Asthma, and Immunology, food allergy symptoms “can appear at any age,” and the organization adds, you can develop an allergy to foods you’ve eaten for years with no problem. Experts don’t always know why someone will develop a food allergy as an adult, but people with eczema, asthma, seasonal allergies, exposure to toxins, or who have a non-varied diet seem to be more prone than others. In addition, many foods have cross-reacting antigens that you can also inhale, like tree pollen. One of the pathways of the immune system, the production of IgG4, may also temper specific allergic reactions to some foods and make them less severe or even eliminate symptoms altogether. 

Allergens aren’t the only culprit when food makes you react. Food sensitivities can also cause an impact on your body, and make you feel terrible. Unlike food allergies, food sensitivities don’t make themselves known immediately. A food you are sensitive to, but not allergic to, will begin to cause symptoms between 3 and 72 hours after you consume it. Because there is such a delay in the onset of reactions, food sensitivities can be much more difficult to tie to specific foods. With allergies, you can look at your plate and greatly narrow the possibilities for what caused you to react, but with sensitivities, anything consumed over the last three days could be the culprit. Unlike food allergies, which activate an IgE reaction, food sensitivities are likely caused by an IgG reaction. Other molecules like IgA can play a role as well, but IgG is the most common culprit. 

Food sensitivities can cause a range of health problems and varied symptoms. Brain fog and lack of clear thinking, faulty memory, tiredness and lack of energy, irritability, bloating, intestinal cramping, watery stools, cracked skin, rashes, puffiness, and other symptoms can all be evidenced after various food sensitivities. Food sensitivities usually begin in the gut, particularly if your microbiome is disturbed. Bouts of food poisoning, antibiotic use, eating too little fiber and too much sugar and processed foods, and illness can all damage the microbiome. A healthy microbiome is necessary to keep a balance of beneficial bacteria and other organisms in the gut to properly digest foods and eliminate waste products, ensuring that you absorb the nutrients you need while adequately getting rid of toxins. A damaged microbiome makes it more likely that you’ll react to various foods, and continuing to eat foods that you react to will further damage the microbiome.

A damaged microbiome doesn’t just affect your extraction of nutrients and elimination of waste products, although that’s bad enough. The inability to extract nutrients efficiently can make you sicker by weakening your immune system, and the accumulation of waste products can increase your toxicity, eventually damaging your liver and kidneys in addition to your gut. A damaged microbiome causes inflammation in the gut and foods that you are sensitive to contribute to inflammation through IgG reactions. 

Some foods may even trigger the release of C3d (also known as “complement”). The body releases complement to signal to the immune system that a serious threat is present, and to attack hard. The complement release triggers a flood of cytokines, the immune system’s heavy hitters, that flood in. This is also known as a “cytokine storm,” because of the ferocity of the response. In fact, sometimes this “cytokine storm” is too intense, especially in healthy people whose immune systems can mount a strong response, and can cause severe damage and inflammation. It’s theorized that “cytokine storms” are the events that may have led to so many deaths of young, healthy people in the 1918 flu pandemic, and why some healthy athletes may have had such strong reactions to COVID-19. In terms of food sensitivities, a complement reaction may supercharge the strength of the immune response (by up to 1,000 times!), and cause worse inflammation in the intestinal wall. 

The constant, or chronic, inflammation of the intestinal wall risks loosening the tight junctions between cells in that wall, allowing leakage of foreign material, bacteria, and foods into the bloodstream (also known as intestinal permeability or leaky gut), and triggering the release of zonulin. Zonulin is a protein that increases the permeability of tight junctions between cells of the wall of the digestive tract, meaning that its release perpetuates a leaky gut, and its presence in the gut indicates intestinal permeability. When zonulin is released, it changes the permeability of intestinal epithelial cells by regulating the state of tight junctions. Increased intestinal permeability can lead to abnormal activation of intestinal mucosal immune and bacterial translocation, then inducing systemic inflammation. In other words, bacteria can spread throughout the body causing inflammation elsewhere in the body, including muscles and other organs, including the brain. This is why we can feel achy and tired, have brain fog, and just feel bad overall from food reactivity. 

Zonulin is the only physiologic modulator of intercellular tight junctions described so far that is involved in the trafficking of macromolecules and, therefore, in tolerance/immune response balance. When the zonulin pathway is deregulated in genetically susceptible individuals, autoimmune disorders can occur. Both animal studies and human trials using the zonulin synthetic peptide inhibitor AT1001 (now named Larazotide acetate) established that zonulin is integrally involved in the pathogenesis of autoimmune diseases. This new paradigm subverts traditional theories underlying the development of these diseases and suggests that these processes can be arrested if the interplay between genes and environmental triggers is prevented by re-establishing the zonulin-dependent intestinal barrier function. Both animal models and recent clinical evidence support this new paradigm and provide the rationale for innovative approaches to prevent and treat autoimmune diseases. So what does this mean? It means, first, that the continued release of zonulin from food sensitivities and allergies can not only risk autoimmune diseases of the gut like Crohn’s Disease, and Irritable Bowel Syndrome, but possibly other autoimmune diseases as well. Secondly (and luckily), reversing the release of zonulin in the gut can stop the progression of autoimmune diseases, and stop them from occurring in the first case if you can intervene early enough to stop the opening of tight junctions in the intestines by eliminating foods that you are sensitive or allergic to from your diet and by repairing the microbiome.  

So how can you find out if you have food allergies or sensitivities, and how do you fix them? The very first thing to do is to have an assessment done through food allergy and sensitivity testing, followed by a consultation with a nutritionist or other practitioner to plan an elimination diet. The gold standard of allergy and sensitivity testing is the P88 test offered by Precision Point Diagnostics (requires a provider’s order) and available both as a test using a phlebotomist as well as the P88-DIY available as a home test. This test evaluates 388 separate reactions involving immune response to foods – both as allergies and as sensitivities. Eighty-eight separate foods are evaluated for IgE, IgG, IgG4, and complement specific to each patient. This allows you to find out your food allergies (IgE), sensitivities (IgG), blocking potential to specific food allergies (IgG4), and whether complement is likely to exacerbate the severity of the reaction (C3d). This test comes with a comprehensive color-coded report that details your degree of reactivity to each food tested and a personalized elimination diet.  

An elimination diet is a key step to help repair the microbiome and intestinal lining of the gut. Foods that you tested positive for will be eliminated and gradually reintroduced, both as a check on how well you can tolerate them and to eventually retrain your gut to enjoy many of the foods that used to bother you. Advanced intestinal barrier testing is also available through Precision Point Diagnostics, which includes zonulin and other markers to assess damage to the gut resulting from food allergies and sensitivities. The Gut-Ox Stress test available from Precision Point Diagnostics takes this analysis even further by tracing not only the overall state of the gut but also its impact on oxidative stress and inflammation throughout the body. 

Once your testing assesses the state of your food allergies and sensitivities, the report will help you repair your microbiome through food elimination and supplementation and eventually reintroduce foods. Not only do most patients feel an alleviation of their symptoms, losing the gut cramping and pain, feeling more regular, more focused, and clear-headed, and seeing clearer skin and less bloating, but many can eventually reintroduce their favorite foods. Food allergies and sensitivities can wreak havoc on your health, but they can often be reversed following accurate identification of which foods are triggers.

Authors

  • Gez Agolli, DrPH PhD MBBS

    Dr Gez Agolli is the Co-founder of Progressive Medical Centers in Atlanta (the largest integrative clinic in the SE for over 25 years treating over 45,000 patients) & co-founder of Precision Point Diagnostics (High complexity CLIA-certified lab). Dr. Agolli is passionate about integrative medicine and believes we live in an exciting time in medical history. Why? Medical science is finally recognizing that “Chronic” disease is not inherited but mostly due to a multitude of issues such as immune deficiency, toxic exposure, inflammation, hormonal imbalance, nutritional deficiency, stress, and gut dysbiosis "Leaky Gut". "ROOT Cause Medicine" Therefore, Dr Agolli has devoted his professional career to developing integrative clinics & training over 200 practitioners to think outside the box to practice functional/integrative medicine. He truly embraces this philosophy personally and professionally. Dr Agolli has hosted over 500 radio shows and podcasts (Rethink Myhealth) discussing current medical topics that educate and inform the general public on cutting-edge, evidence-based medical treatments and therapies. He currently mentors and coaches 15 practitioners (MDs, NPs, NDs, RDs, DCs) and a staff of over 75.

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  • Cheryl Burdette, ND

    Dr. Burdette is Director of Education at Progressive Medical Center, one of the largest integrative clinics in the Southeast. She is the co-founder of Precision Point Diagnostics, a laboratory that focuses on gut based health and wellness. There she designs clinical profiles and trains clinicians on their utilization. She has a rich history in the integrative medicine laboratory space. She designed and teaches the clinical curriculum for Origins Incubator, a practice management group, that has helped to launch many successful practitioners. She is the Educational Director and on the board of advisors for Xymogen, a physician line pharmaceutical. She is on the board of advisors for TheraDura Diagnostik, a German based lab company. She serves on IRB boards, is involved in study design and translational research, and has lectured extensively worldwide. She directs an accredited Naturopathic residency at Progressive. Her passion is teaching about the practice of Integrative and Naturopathic Medicine, to increase awareness of evidenced-based natural therapies, to both rule in and rule out tools that are effective in patient care.

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  • Robert Thomas

    Robert Thomas is a medical writer with long experience in healthcare and policy analysis. Mr. Thomas’s background in education in both public and private institutions have given him a firm foundation in research, analysis, and writing on a variety of intersecting topics in medicine and public policy. Aside from his research and writing career, Mr. Thomas is a former COO of a functional diagnostic laboratory, the former managing director of a private supplemental education group, and a former Director of Policy Debate at Stanford University.

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