Gluten intolerance can lead to digestive problems such as excess gas, stomach pain, diarrhea, or constipation. Because these symptoms are also common in other digestive conditions, gluten intolerance is often difficult to diagnose.

This condition may not have a specific cause or can be associated with celiac disease. When abdominal discomfort occurs after eating foods with gluten, it is important to consult a doctor for an accurate diagnosis.

Gluten sensitivity can affect both children and adults and is caused by difficulty digesting gluten, a protein found in wheat, barley, and rye.

Main symptoms

The most common gluten intolerance symptoms include:

Chronic diarrhea or constipation
Bloating or abdominal swelling
Recurrent stomach pain
Gas or flatulence
Nausea or vomiting
Feeling of heaviness after meals
Pale, bulky, or foul-smelling stools
Unintentional weight loss
Persistent fatigue or excessive tiredness
Headaches or migraines
Joint or muscle pain
Skin problems, such as rash, itching, or dermatitis herpetiformis
Iron-deficiency anemia
Difficulty concentrating or brain fog
Mood changes, such as irritability, anxiety, or depression
Mouth ulcers or sores
Tingling or numbness in the hands or feet
Low bone density or osteoporosis

Digestive symptoms are the most frequent and are usually linked to the body’s reduced ability to process gluten, which can interfere with nutrient absorption and cause long-lasting intestinal discomfort.

Non-digestive symptoms may also occur, even without stomach or bowel issues, especially in people with undiagnosed celiac disease. In some cases, they may also appear with non-celiac gluten sensitivity, although the exact cause is not fully understood.

These symptoms typically develop after eating foods that contain wheat, barley, or rye and may be mistaken for conditions like irritable bowel syndrome.

First symptoms of gluten intolerance in adults

The first signs of gluten intolerance in adults often appear days or weeks after regular consumption of wheat, barley, or rye and mainly affect the digestive system.

The most frequent symptoms are bloating, diarrhea, constipation, and excess gas. Other symptoms may include fatigue, headaches, difficulty concentrating, anemia, hair loss, skin irritation, joint pain, anxiety, or menstrual changes.

In cases of non-celiac gluten sensitivity, symptoms may appear within hours of eating gluten and usually improve once gluten is removed from the diet.

How to know if it is intolerance

To determine whether gluten intolerance is caused by celiac disease or non-celiac gluten sensitivity, a doctor will assess symptoms as well as personal and family medical history.

Blood tests are often ordered to detect antibodies linked to celiac disease, and in some cases, an intestinal biopsy may be recommended.

Additional tests may be used to rule out wheat allergy. Only after excluding other conditions can non-celiac gluten sensitivity be suspected, especially if symptoms improve after gluten is removed from the diet.

The diagnosis of non-celiac gluten sensitivity is generally based on eliminating gluten for a few weeks, followed by controlled reintroduction under medical supervision. This helps confirm whether symptoms are related to gluten while avoiding unnecessary restrictions or misdiagnosis.

How to live with gluten intolerance

After a diagnosis of gluten intolerance, all foods containing gluten should be removed from the diet, including bread, pasta, cookies, cakes, and other products made with wheat, barley, or rye.

There are now many gluten-free alternatives made with rice, corn, cassava, potato starch, or quinoa flours. These products must be clearly labeled as “gluten-free” and are safe to eat.

It is also important to carefully check labels on processed foods, as some may contain hidden gluten or trace amounts due to cross-contamination. Examples include sausages, kibbeh, cereals, meatballs, canned soups, and packaged sauces.