Celiac Disease and the Gut Barrier

Share
Print Friendly, PDF & Email

By Finn Corkum-Plaster, Dietetic Intern

Summary of Celiac Disease

When a person with celiac disease eats gluten, their immune system reacts and damages the lining of their small intestine. The small intestine is lined with little finger-like structures called villi. When someone with celiac eats gluten the villi can become damaged and flattened. This is important because the longer the villi, the more surface area there is for nutrients to be absorbed. Someone with damaged villi can have malabsorption (difficulty absorbing nutrients). This can lead to vitamin and/or nutrient deficiencies.

The Gut Barrier

The gut barrier helps regulate what passes from inside the intestines into the body. When we consume wheat proteins, they can resist breaking down in the intestine and trigger zonulin. Zonulin is a protein that helps maintain integrity of the gut barrier, like a castle guard. Specifically, it is the gatekeeper that controls the passageways of the gut known as tight junctions1. In celiac disease, changes in the gut barrier and the immune response to gluten contribute to damage in the intestinal lining2.

Think of the gut barrier as a castle wall. Tight junctions help control the gates between intestinal cells.

With celiac disease, the immune response activates specific cells called intraepithelial lymphocytes². These immune cells can recognize stress-related proteins on the surface of intestinal cells and damage those cells³. This contributes to the breakdown of the intestinal lining². However, adhering to a gluten-free diet is the only established therapy for most people with celiac disease².

The function of the small intestine epithelial cells (the cells lining the intestine) can be affected during an active celiac disease flare-up. They can also be affected during celiac disease when symptoms have decreased (remission). The functions of the cells are: regulating stress on cells, creating DNA for cells, DNA repair, energy production and creating proteins4. 

What is the Gut Barrier?

Proteases!

Proteases are groups of enzymes that help digest proteins and can also affect the gut barrier. Protease function is a significant factor in the gut’s well-being and digestion. Proteolytic activity is the breakdown of proteins by proteases6. Problems with proteolytic activity have been linked to conditions such as irritable bowel syndrome (IBS), Inflammatory bowel disease (IBD), and celiac disease (CD)5.

Gut Microbiota and It’s Function

The gut has a microbiota; this is the ecosystem of microorganisms that live in the gut and help break down foods. It is like a tiny city in your intestines, and all the people are little organisms that help your gut function. A healthy microbiota is very important for a healthy person. 

The gut microbiota helps maintain the gut barrier. Some gut microorganisms can break down parts of gluten. Researchers are studying how changes in the gut microbiota may contribute to celiac disease6. It is important to state that the gut microbiota does not make gluten safe for someone with celiac disease.

Non-Celiac Wheat Sensitivity (NCWS)

Non-celiac wheat sensitivity (NCWS) is a condition where a person may deal with stomach and brain symptoms caused by eating wheat. This sensitivity should be considered once celiac disease and a wheat allergy are ruled out by a doctor. Non-celiac wheat sensitivity is often used interchangeably with non-celiac gluten sensitivity⁷. However, NCWS is different from celiac disease or a wheat allergy. Symptoms of NCWS include fatigue, brain fog and headaches⁸.

Damage to the villi is not an established feature of NCWS⁹. NCWS is not an autoimmune disease like celiac disease or an allergic condition like a wheat allergy.

A wheat allergy is different from celiac disease because it involves an allergic reaction. Symptoms can include skin rash and shortness of breath. Some reactions can be severe, including anaphylaxis¹⁰. Celiac disease is an autoimmune condition that can cause stomach pain, brain fog, headaches, damaged villi and many other symptoms.

While NCWS can cause symptoms similar to celiac disease, managing it involves individual dietary approaches. This usually involves a gluten-free or wheat-free diet. It can also include parts of a diet called the low-FODMAP diet⁸.

The low-FODMAP diet temporarily limits certain fermentable carbohydrates that can cause gas, bloating and other digestive symptoms in some people. The restrictive phase is meant to be temporary and should be done with the support of a dietitian. Foods are then reintroduced to help identify personal food triggers and avoid unnecessary restrictions. Also, the low-FODMAP diet does not replace a gluten-free diet for a person with celiac disease.

Keeping Your Gut Barrier Healthy!

The Foods We Eat

A traditional American diet is usually high in processed foods, saturated fats and is low in fiber.  Eating to support the gut barrier and overall health involves incorporating a variety of whole foods; whole grains, lean proteins, fruits and vegetables11.  Celiac disease develops in people with a genetic susceptibility and is triggered by gluten.

Processed foods have been changed from their original form. Processing does not automatically make a food unhealthy. Examples of healthy, less-processed, and budget-friendly foods include frozen fruit and vegetables, canned beans, and brown rice.

Saturated fats are fats that are typically solid at room temperature. Eating too much saturated fat, like butter, bacon fat or coconut oil can raise LDL cholesterol, which contributes to plaque buildup in arteries. Eating too much saturated fats can be hard on your body, specifically your heart, over time. However, eating healthfully includes moderation, it’s ok to eat these fats! Switching saturated fats out for unsaturated fats like monounsaturated and polyunsaturated fats are healthy for your heart12. Some healthy fat options include canola or vegetable oil (oils liquid at room temperature), avocados, nut butters and nuts and seeds.

Fiber is a carbohydrate that your body cannot digest. Fiber is super helpful because it passes through your body and helps digestion. It also contributes to your gut microbiota. Fiber comes from whole grains, beans, fruits and vegetables. Some gluten-free whole grain options include brown rice, buckwheat, amaranth and quinoa.

Mediterranean Diet and Plant-Forward Foods

Eating patterns that can support overall health include the Mediterranean diet and a plant-forward diet. The Mediterranean diet consists of fruits, vegetables, whole grains, healthy fats, lean proteins and lots of fiber. A plant-forward diet focuses on getting necessary nutrients from plants. Such as protein from soy, beans and nuts. Similarly to the Mediterranean diet, it also involves eating lots of fruits, vegetables and whole grains11.

Where To Go from Here?

With all that information you may be wondering: What should I do now? If you are experiencing symptoms of celiac disease, such as digestive symptoms (for example stomach pain and bloating), and headaches after eating gluten it is best to talk to your doctor. It is important to get tested for celiac disease before starting a gluten-free diet13.

References

  1. Granizo Bermejo, D., García-Pérez-de-Sevilla, G., & Molina-López, A. (2026). Intestinal permeability and the zonulin pathway: Tight junctions, mucosal immunity, dietary modulators and clinical relevance. Frontiers in Nutrition, 13, 1938370. PubMed Central. doi.org/10.3389/fnut.2026.1938370.  
  2. Shaikh, S., & Jain, P. (2026). Innate immune dysregulation in celiac disease and refractory celiac disease: mechanisms, management and emerging therapies. Frontiers in immunology, 17, 1926029. doi.org/10.3389/fimmu.2026.1926029.
  3. Allegretti, Y. L., Bondar, C., Guzman, L., Cueto Rua, E., Chopita, N., Fuertes, M., Zwirner, N. W., & Chirdo, F. G. (2013). Broad MICA/B expression in the small bowel mucosa: a link between cellular stress and celiac disease. PloS one, 8(9), e73658. doi.org/10.3389/fimmu.2024.1368586.
  4. McCreery, C. V., Alessi, D., Mollo, K., Fasano, A., & Zomorrodi, A. R. (2025). Investigating intestinal epithelium metabolic dysfunction in celiac disease using personalized genome-scale models. BMC medicine, 23(1), 95. doi.org/10.1186/s12916-025-03854-0.
  5. Rao, S., & Grover, M. (2023). Intestinal proteases. Current opinion in gastroenterology, 39(6), 472–478. doi.org/10.1097/MOG.0000000000000972.  
  6. Zolnikova, O., Dzhakhaya, N., Bueverova, E., Sedova, A., Kurbatova, A., Kryuchkova, K., Butkova, T., Izotov, A., Kulikova, L., Yurku, K., Chekulaev, P., & Zaborova, V. (2023). The Contribution of the Intestinal Microbiota to the Celiac disease Pathogenesis along with the Effectiveness of Probiotic Therapy. Microorganisms, 11(12), 2848. doi.org/10.3390/microorganisms11122848.
  7. Cotton, C., Raju, S. A., Ahmed, H., Webster, G., Hallam, R., Croall, I., Coleman, S., Trott, N., Rej, A., Shiha, M. G., Aziz, I., & Sanders, D. S. (2023). Does a Gluten-Free Diet Improve Quality of Life and Sleep in Patients with Non-Coeliac Gluten/Wheat Sensitivity?. Nutrients, 15(15), 3461. doi.org/10.3390/nu15153461.
  8. Piotin, A., & de Blay, F. (2025). Investigating Non-celiac Wheat Sensitivity: A Comprehensive Review of Pathophysiology Underlying Clinical Implications. Clinical reviews in allergy & immunology, 68(1), 94. doi.org/10.1007/s12016-025-09106-6.
  9. Williams, C., Smith, N., & Rostami, K. (2023). Transient non-coeliac gluten sensitivity (NCGS) with markedly reduced villous height/crypt depth ratio. Gastroenterology and Hepatology from Bed to Bench, 16(2), 222–224. PubMed Central. doi.org/10.22037/ghfbb.v16i2.2755.
  10. Zheng, W., Wai, C. Y. Y., Sit, J. K. C., Cheng, N. S., Leung, C. W. M., & Leung, T. F. (2024). Routinely Used and Emerging Diagnostic and Immunotherapeutic Approaches for Wheat Allergy. Biomedicines, 12(7), 1549. doi.org/10.3390/biomedicines12071549.
  11. Moleriu, L. C., Lupusoru, R., Marin, R. C., Muntean, C., Piroș, T., Vlad, D. C., Dumitrașcu, A. L., & Dumitrașcu, V. (2026). Food as Friend or Foe: A Decadal Narrative Review of Dietary Patterns as Determinants of Gastrointestinal Pathophysiology and Clinical Outcomes (2015-2025). International journal of molecular sciences, 27(6), 2837. doi.org/10.3390/ijms27062837.
  12. Fats in Foods. (2026). Www.Heart.Org. www.heart.org/en/healthy-living/healthy-eating/eat-smart/fats/fats-in-foods.
  13. National Institute of Diabetes and Digestive and Kidney Disease. (2019, February 16). Celiac disease. National Institute of Diabetes and Digestive and Kidney Diseases. www.niddk.nih.gov/health-information/digestive-diseases/celiac-disease.