Food Sensitivities on the Rise? Gut Health and Immune Overload Are Connected
What’s Causing Your Food Sensitivities?
If you feel like your body is suddenly reacting to more and more foods, you’re not alone. Maybe you could eat dairy, eggs, or gluten without issue before, but now even a small bite triggers bloating, fatigue, rashes, or brain fog. It can be confusing and frustrating. You might even start to wonder: “Am I allergic to everything?”
We often see this pattern, and one major contributor is something called leaky gut, paired with an overloaded immune system. Let’s break it down together so you can understand what might be happening inside your body and, more importantly, what you can do about it.
What Is Leaky Gut?
Your gut is home to a long tube called the intestinal lining. Think of it like a finely woven net that decides what gets into your bloodstream and what stays out. Normally, this lining lets in nutrients from your food but keeps out things like undigested food particles, bacteria, and toxins.
When that net becomes damaged or "leaky," larger and unwanted particles can pass through. This is known as intestinal permeability, or more commonly, leaky gut. When things that aren’t supposed to enter your bloodstream sneak in, your immune system sees them as invaders and reacts.
Over time, these immune reactions can start happening every time you eat certain foods. Your body becomes more reactive, and you might find yourself unable to tolerate foods you once loved.
How the Immune System Gets Overwhelmed
Your immune system is like your body's personal security team. Its job is to protect you from harm, including viruses, bacteria, and toxins. But when it gets overwhelmed, whether from stress, poor sleep, environmental toxins, infections, or a leaky gut, it starts to lose its ability to tell friend from foe.
Instead of calming down after doing its job, your immune system may stay on high alert. And in this heightened state, it might start attacking harmless things, like proteins in your food. This is one reason food sensitivities seem to grow over time: your immune system is essentially tired and overworked.
Why More Foods? Why Now?
So why does it feel like you're reacting to more foods than ever?
Accumulated Stress on the Gut: Over time, things like antibiotics, processed foods, alcohol, chronic stress, and even medications can wear down your gut lining.
Cross-Reactivity: Sometimes your immune system thinks different foods are similar and starts reacting to those, too. For example, if you react to gluten, you might also start reacting to oats or dairy due to similar protein structures.
Poor Gut Health: Imbalanced gut bacteria (called dysbiosis) can increase inflammation and weaken the gut lining.
Mast Cell Activation: Certain cells in your body that release histamine can become overly sensitive, making you react to foods, smells, and even temperature changes.
Too Many Toxins: Environmental toxins, mold, and heavy metals can burden your immune system, making it more reactive.
Signs That Leaky Gut and Immune Overload Might Be a Problem
You react to foods you used to tolerate
You feel better with a limited diet, but worse when you try new foods
You have digestive symptoms (bloating, gas, diarrhea, or constipation)
You struggle with fatigue, brain fog, skin issues, or joint pain
You have been diagnosed with autoimmune conditions
You feel worse after periods of stress or illness
If this sounds familiar, your body might be signaling that your gut and immune system need some attention.
Functional Testing: Understanding What Your Body Needs
One of the most helpful tools to determine what is going on in your body is advanced lab testing. These tests go beyond standard blood work to help identify hidden imbalances that may be contributing to food reactivity.
1. Comprehensive Stool Analysis
This test evaluates your gut microbiome, inflammation markers, digestion, and potential pathogens. It can reveal imbalances in bacteria, yeast overgrowth, and whether your gut lining is inflamed or leaking.
2. Food Sensitivity Testing
Some practitioners may use IgG or IgA-based food sensitivity tests to see how your immune system is responding to different foods. While these tests aren’t perfect, they can offer useful clues when interpreted with your symptoms and history.
3. Intestinal Permeability Testing
Specific tests can measure how "leaky" your gut is by assessing the movement of molecules through your intestinal lining. This can help determine if your gut barrier needs repair.
4. Micronutrient Testing
Nutrient deficiencies, such as low levels of zinc, vitamin D, or glutamine, can impact gut health and immune function. Testing can guide more targeted supplementation.
5. Inflammatory and Immune Panels
Markers like CRP (C-reactive protein), cytokines, or immune cell balances can provide insight into how inflamed or overloaded your immune system might be.
Healing the Gut and Calming the Immune System
You can often calm food reactivity by working to heal your gut and support your immune system. Here’s a roadmap to get started:
1. Remove Irritants
Take a break from foods that are causing noticeable symptoms. Common culprits include gluten, dairy, soy, sugar, and processed foods. Reducing alcohol, caffeine, and artificial additives can also give your gut a break.
2. Focus on Gut-Healing Foods
Support your gut lining with foods like:
Bone broth
Steamed vegetables
Cooked squashes and sweet potatoes
Omega-3 rich fish
Fermented foods (if tolerated)
Herbal teas like chamomile or ginger
3. Rebuild with Nutrients
Targeted supplements may support your gut and immune health. Some commonly recommended ones (under practitioner guidance) include:
L-glutamine
Zinc
Vitamin D
Omega-3s
Probiotics and prebiotics
These can help repair the gut lining, balance your microbiome, and reduce inflammation.
4. Lower Your Total Stress Load
Stress isn’t just mental, it affects your gut and immune system too. Consider:
Mindfulness or meditation
Gentle movement like yoga or walking
Getting enough sleep
Spending time in nature
5. Reintroduce Foods Slowly and Strategically
Once your gut begins to heal, many people can start tolerating foods again. This process should be slow and guided, ideally with a knowledgeable practitioner who can help you track symptoms and watch for hidden triggers.
If you’re reacting to more foods than ever, it doesn’t mean your body is failing. In fact, it’s a sign your body is doing exactly what it was designed to do: protect you.
Understanding the connection between your gut and your immune system gives you the power to take steps toward healing. With the right support, a tailored plan, and some patience, it is possible to calm your system and regain food freedom.
References
Albert-Bayo, M., et al. (2019). Intestinal Mucosal Mast Cells: Key Modulators of Barrier Function. Frontiers in Immunology.
Valitutti, F., et al. (2025). Intestinal permeability, food antigens and the microbiome. Frontiers in Allergy.
Poto, R., et al. (2023). The Role of Gut Microbiota and Leaky Gut in Food Allergy. Nutrients.
Zhang, L., et al. (2016). Mast Cells and Irritable Bowel Syndrome: From the Bench. Journal of Neurogastroenterology and Motility.
Ishihara, N., et al. (2022). Spi-B alleviates food allergy by securing mucosal barrier. Frontiers in Allergy.
Andreou, E., et al. (2025). Boosting Immunity Through Nutrition and Gut Health. Nutrients.
