What Is Gluten Sensitivity? Its Causes, and Does Gluten Cause Cancer?

Gluten sensitivity (gluten intolerance) is a condition in which the body reacts abnormally to gluten , a protein found in grains such as wheat, barley, and rye. Eating gluten-containing foods can cause various symptoms, particularly digestive problems. Although often confused with celiac disease or wheat allergy, it is a different condition (these differences are discussed below). In people with gluten sensitivity, consuming gluten does not directly cause autoimmune damage through the immune system; however, they may feel unwell and their quality of life may decline. What causes gluten sensitivity, what are its symptoms, and is complete gluten avoidance necessary? 

What Is Gluten Sensitivity (Gluten Intolerance)?

Gluten is a group of proteins found in grains such as wheat, barley, and rye that gives baked goods elasticity and chewiness. For most people, gluten is a harmless food component that causes no problems. However, people with gluten sensitivity have difficulty digesting gluten or experience unwanted bodily reactions when consuming it. In medical literature, this condition is also called non-celiac gluten sensitivity (NCGS) .

In gluten sensitivity, exposure to gluten causes digestive problems such as bloating, gas, or diarrhea, and sometimes systemic symptoms such as headaches, fatigue, and joint pain. It differs from celiac disease because the response to gluten does not cause the immune system to attack its own tissues directly (an autoimmune reaction). The lasting intestinal damage seen in celiac disease is therefore not typically found in gluten sensitivity. It differs from wheat allergy because it does not cause classic allergic reactions such as skin rashes or anaphylaxis. Gluten intolerance instead behaves more like a food sensitivity .

The exact prevalence of gluten sensitivity is unknown. While celiac disease affects approximately less than 1% of the general population, some studies suggest that non-celiac gluten sensitivity may affect 5-10%. The recent popularity of gluten-free diets has increased the number of people diagnosing themselves with gluten intolerance. It is important to remember that not every episode of indigestion or bloating is necessarily caused by gluten (we discuss this under The Nocebo Effect ). Diagnosing true gluten sensitivity can sometimes be difficult because there is no definitive laboratory test specific to the condition; diagnosis usually follows the exclusion of other diseases.

Causes and Risk Factors for Gluten Sensitivity

The underlying causes of gluten sensitivity are not fully understood. Its causes are usually multifactorial and can be summarized as follows:

• Intestinal Permeability and the Microbiota: Some experts suggest that increased intestinal permeability, known as “leaky gut,” may allow undigested gluten to enter the bloodstream and cause sensitivity. Imbalances in intestinal flora may also contribute to an inability to tolerate gluten.
• Genetic Predisposition: Certain genetic factors (HLA-DQ2/DQ8 genes) are known to play a role in celiac disease. Although these genes are not required for gluten sensitivity, a family history of celiac disease or other autoimmune diseases may be a risk factor.
• Diet and Environmental Factors: A diet very high in gluten may contribute to the development of intolerance over time in some people. Environmental factors such as frequent antibiotic use, stress, and previous infections are also thought to trigger sensitivity.
• Relationship With Irritable Bowel Syndrome (IBS): Gluten sensitivity can be confused with IBS or coexist with it. Some people with IBS may be sensitive to gluten or to carbohydrates in wheat called FODMAPs . They may therefore feel better after eliminating gluten even when this does not reflect true gluten intolerance.

Although the exact cause of gluten intolerance remains unclear, risk factors may include family history, previous inflammatory bowel disease or intestinal infections, and female sex (gluten sensitivity is reported somewhat more frequently in women). Doctors may also suspect non-celiac gluten sensitivity in people with persistent digestive symptoms after celiac disease has been ruled out.

What Are the Symptoms of Gluten Sensitivity?

Symptoms vary between individuals, but the most common complaints involve the digestive system. The following table lists symptoms of gluten sensitivity with brief explanations:

As the table shows, gluten sensitivity symptoms are highly varied. Although digestive symptoms are most common, the stress gluten places on the body can also have systemic effects. For example, persistent diarrhea can disturb electrolyte balance, reduce nutrient absorption, and cause vitamin deficiencies; these may explain fatigue, headaches, or mood changes. These symptoms can also occur in other diseases. If you have several of the above complaints, particularly if you believe they are linked to gluten-containing foods, seeing a doctor for an accurate diagnosis is important.

Diagnosis and Assessment

Doctors perform several assessments to clarify a diagnosis of gluten sensitivity, because symptoms can resemble other conditions such as celiac disease or wheat allergy. The diagnostic assessment usually includes the following steps:

1. Detailed Medical History and Physical Examination: The doctor asks about the symptoms, when they began, and which foods they are associated with. They ask about a family history of celiac disease or allergies and then assess findings from a physical examination, including the abdomen.
2. Laboratory Tests: Blood tests are initially performed to rule out celiac disease. Anti-tTG (tissue transglutaminase) antibodies, EMA (endomysial) antibodies , and other celiac-related antibody tests are requested. A complete blood count to check for anemia and, if necessary, tests for nutritional deficiencies may also be performed. If wheat allergy is suspected, specific IgE allergy tests may be requested.
3. Endoscopy and Biopsy: If celiac tests are positive or suspicion is strong, endoscopy is performed to obtain a small intestinal biopsy. If the biopsy shows villous damage, celiac disease is diagnosed. In gluten sensitivity, this biopsy is usually normal or may show minimal inflammation.
4. Elimination Diet and Challenge: If celiac and allergy tests are negative, an elimination diet may be tried under medical supervision. The patient is asked to follow a gluten-free diet for a specified period, such as 4-6 weeks, while symptoms are monitored for improvement. Gluten is then reintroduced as a challenge to see whether symptoms return. Clear improvement without gluten and worsening after reintroduction support a diagnosis of non-celiac gluten sensitivity .
5. Excluding Other Causes: Because lactose intolerance, FODMAP intolerance, and irritable bowel syndrome can cause similar symptoms, the doctor will also consider these conditions. Additional tests may be performed if necessary. If these investigations identify no other cause and a gluten-free diet brings relief, a diagnosis of gluten intolerance is confirmed.

The most important part of diagnosis is not to miss celiac disease. Celiac disease is a serious autoimmune disorder requiring a strict lifelong gluten-free diet. Medical assessment before trying a gluten-free diet on your own is therefore important. If someone eats gluten-free for months before testing, celiac tests may be falsely negative. Necessary medical tests should therefore be performed before completely eliminating gluten.

Abdominal discomfort and bloating are common complaints in people with gluten sensitivity. The image above highlights a red area representing abdominal pain.

How It Differs From Celiac Disease and Wheat Allergy

Gluten sensitivity is often confused with celiac disease or mistaken for wheat allergy , but these are three different conditions. Their differences can be summarized as follows:

• Celiac Disease: This is an autoimmune response to gluten consumption. When someone eats gluten, the immune system attacks their own small intestinal tissue, damaging its absorptive surface. Symptoms include diarrhea, abdominal pain, weight loss, and growth retardation in children. Diagnosis uses blood tests and intestinal biopsy. Treatment is a very strict lifelong gluten-free diet. Celiac disease can be regarded as the most severe and clearly defined form of gluten sensitivity.
• Wheat Allergy: The problem here is wheat itself, potentially any of its proteins, rather than specifically gluten. Like other food allergies, wheat allergy is an IgE-mediated immune response. Eating wheat-containing foods can quickly cause typical allergic reactions such as hives, itching, a runny nose, or shortness of breath. Some cases even carry a risk of anaphylaxis (severe allergic shock). Wheat allergy usually appears in childhood, and some children outgrow it. Diagnosis uses a skin-prick test or a blood test for specific IgE. Treatment requires avoiding wheat and wheat products, although grains such as barley and rye may be tolerated because wheat proteins are the allergens.
• Non-Celiac Gluten Sensitivity: There is neither autoimmune damage as in celiac disease nor an immediate IgE-mediated reaction as in wheat allergy. It is more of a functional digestive sensitivity. Gluten-containing foods cause symptoms such as abdominal pain, bloating, diarrhea, headaches, and fatigue, but tests do not identify celiac disease or allergy. No clear small intestinal damage is seen. Symptoms improve when gluten is removed and return when it is reintroduced. Diagnosis therefore follows exclusion of the other two conditions and a dietary trial. Although treatment is not definitive, restricting gluten to a tolerable level and following a balanced diet are recommended instead of eliminating it completely. Gluten sensitivity is as rare as celiac disease and may not be as widespread as commonly believed.

In summary, celiac disease and wheat allergy are more clearly defined conditions that can be demonstrated by tests, while gluten intolerance is a diagnosis of exclusion . All three involve discomfort from gluten-containing foods, but their underlying mechanisms differ. Treatment and dietary approaches therefore differ too. If you suspect a gluten-related problem, medical supervision is essential to determine which group you fall into.

Tips for a Gluten-Free Lifestyle

For people diagnosed with gluten sensitivity (or celiac disease), a gluten-free lifestyle is the most important treatment. Eating gluten-free may initially seem difficult because many everyday foods contain gluten. However, gluten-free product choices have increased, and informed choices can provide a healthy, balanced gluten-free diet. Here are some precautions and suggestions:

• Know Which Grains Contain Gluten: First, be aware of which foods contain gluten. Wheat, barley, and rye definitely contain gluten. Oats are generally considered gluten-free, but contamination can occur during processing, so choose oats labeled “gluten-free.”
• Make a Habit of Reading Labels: Always read labels on packaged foods. If the ingredient list includes terms such as wheat flour, malt, starch, or gluten , avoid the product. Sauces, instant soups, processed meats, and even ice cream may contain gluten as a thickener. Choose products bearing a “Gluten Free” logo.
• Watch for Cross-Contamination: When preparing gluten-free foods, avoid using the same surfaces or utensils as for gluten-containing foods. Even cutting gluten-free bread on a board used for regular bread carries a risk of trace contamination. Keeping equipment such as sandwich toasters and baking trays separate is also helpful, particularly for people with celiac disease, for whom this is essential.
• Use Alternative Grains: There are many alternative flours and grains you can use instead of wheat flour. Rice, corn, buckwheat, quinoa, lentil flour, almond flour, and chickpea flour can be used to make bread, pastries, and pasta. These products are naturally gluten-free and provide complex carbohydrates and fiber. Rice and corn pasta or bread made with buckwheat flour, for example, are widely available.
• Eat a Balanced, Nutritious Diet: A gluten-free product is not necessarily healthy. Some ready-made gluten-free products, such as bread or cookies, may contain more sugar and fat than regular versions and be low in B vitamins, iron, and fiber. Even when eating gluten-free, therefore, limit processed foods and choose natural foods. Build a varied diet with vegetables, fruit, nuts, legumes, and protein sources such as meat, fish, chicken, and eggs. Your doctor may recommend supplements for any vitamin or mineral deficiencies if necessary.
• Ask Questions When Eating Out: If eating at a restaurant, ask how the food is prepared. Breadcrumbs, sauces, and marinades may contain gluten. Choosing restaurants with a gluten-free menu makes this easier. Remember that salads may contain croutons and soups may contain flour.
• Pay Attention to Fiber and Probiotic Intake: Eliminating whole grains because of gluten sensitivity may reduce fiber intake. To prevent constipation and maintain intestinal health, get enough fiber from gluten-free grain products, vegetables, fruit, and, if needed, supplements such as psyllium . Support intestinal flora by eating probiotic-rich foods such as yogurt and kefir.
• Be Careful With Alcohol: Beer and malt-containing drinks contain gluten. Wine and distilled spirits such as rakı, vodka, and tequila are generally considered gluten-free. However, you may prefer certified gluten-free products to be certain about additives.
• Seek Support From a Nutrition Professional: When starting a gluten-free diet, support from a dietitian can help you adapt. Professional advice about meeting nutritional needs, alternative recipes, and strategies for eating out can be useful.

Gluten-free packaging often displays a crossed-out wheat-ear symbol and the wording “Gluten Free.” This symbol is an international sign that a product does not contain gluten.

Although these recommendations are particularly essential for people with celiac disease, people with gluten sensitivity also feel much better when taking similar precautions. Remember that living gluten-free is a process , and experience will help you learn what is safe and what is risky over time. Although it may seem restrictive at first, today's many alternatives make a varied eating plan possible.

Gluten and Cancer: Does Gluten Cause Cancer?

One concern about gluten is whether it causes cancer. Some sources, particularly online, claim that gluten is extremely harmful and causes many diseases, including cancer. These claims should be assessed in light of scientific evidence.

First, it is important to state that research to date has found no clear scientific evidence that gluten consumption causes cancer in healthy people. Gluten is not considered a direct carcinogen like tobacco or asbestos. There is therefore no strong justification for healthy people to avoid gluten solely to prevent cancer. Unnecessarily eliminating gluten may actually restrict the diet and deprive people of other nutrients.

There is, however, an exception: people with celiac disease. If celiac disease is untreated, meaning gluten consumption continues, the long-term risk of certain intestinal cancers , such as small intestinal cancer or lymphoma, may increase. This reflects the chronic inflammation caused by celiac disease rather than an effect of gluten on the general population. An increased risk of intestinal lymphoma in undiagnosed celiac disease was observed 30-40 years ago. In people diagnosed and started on a gluten-free diet, however, this risk approaches that of the general population.

Data on gluten sensitivity and cancer are very limited. No increase in risk as clear as that in celiac disease has been found in people with non-celiac gluten sensitivity, because the structural intestinal damage associated with celiac disease does not occur here. Nevertheless, because persistent inflammation and stress are theoretically possible, any long-term risk remains unclear. Current data do not show a convincing link.

Sometimes the nocebo effect also contributes to negative beliefs about gluten. Someone who believes gluten is harmful may feel unwell after consuming it even without a scientifically established effect. Exaggerated media reports about gluten can reinforce this psychological effect. For example, some once-popular health programs spread claims that gluten “sticks inside the body” and “triggers many diseases.” The scientific community has largely been unable to confirm these claims.

In conclusion: Gluten is not considered a direct cause of cancer in healthy people. If you have celiac disease or genuine gluten intolerance , you naturally need to restrict gluten consumption. Even in this situation, your cancer risk will return to normal limits as long as you follow a gluten-free diet. By contrast, no benefit has been demonstrated from unnecessary gluten avoidance in people without gluten sensitivity . Avoiding whole grains may actually reduce dietary fiber and B vitamin intake.

Claims that gluten causes cancer are currently incorrect. Although research continues, there is no indication that everyone needs to eliminate gluten as commonly feared. The important step is to consult a doctor to determine whether you have an individual sensitivity and act according to scientific evidence.

Conclusion

Gluten sensitivity is widely discussed today. Gluten genuinely causes discomfort for some people, and a gluten-free diet may improve their quality of life. However, medical assessment is essential for accurate diagnosis and differentiation rather than self-diagnosis. Celiac disease, wheat allergy, and non-celiac gluten sensitivity are different conditions requiring different approaches.

Remember that a balanced diet is fundamental. If you have gluten sensitivity, you can eat healthily by following gluten-free lifestyle recommendations. Vegetables, fruit, meat, fish, legumes, and gluten-free grains can provide all the nutrients your body needs. Being unable to eat gluten is not an obstacle; proper planning makes a nutritious, enjoyable diet possible.

Finally, generalizations such as “gluten is harmful to everyone” have no scientific basis. Gluten does not cause cancer; on the contrary, whole grains are part of a healthy diet for many people even when they contain gluten. What matters is understanding our bodies, taking symptoms seriously, and choosing the most appropriate diet with professional support if necessary. If you have concerns about gluten, consult a gastroenterologist or dietitian for appropriate information.