Gluten intolerance, or non-celiac gluten sensitivity, shares some of the same symptoms as celiac disease. It can cause considerable discomfort, diarrhea, bloating, abdominal pain, and more.

People with gluten intolerance may experience gastrointestinal symptoms or other symptoms, such as a headache, joint pain, and fatigue, after consuming gluten.

These symptoms typically resolve when someone removes gluten from their diet.

This article will outline seven symptoms that people associate with gluten intolerance, how doctors diagnose it, and how to manage symptoms.

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The exact symptoms of a gluten intolerance can vary from person to person. However, symptoms typically occur after consuming gluten.

People with gluten intolerance may experience the following symptoms when they include glutenous foods in their usual diet.

1. Diarrhea and constipation

Those who report gluten intolerance say IBS-like symptoms, such as diarrhea and constipation, are common.

Occasionally having such digestive issues is expected, but experiencing them on most days can indicate an underlying condition.

People with celiac disease may also experience diarrhea and constipation. They may also have poop that smells particularly unpleasant, as the condition causes poor nutrient absorption.

2. Bloating

Another common symptom that people report in cases of gluten intolerance is bloating. This refers to the feeling of a full stomach that is uncomfortable and lasting. People may also feel a buildup of gas.

Certain foods or drinks, such as vegetables and fizzy drinks, can cause bloating. However, it can happen for a number of different reasons.

In people with gluten intolerance, the feeling of bloating may occur very regularly and is not necessarily related to the amount of food they eat.

3. Abdominal pain

Similarly, several different causes can lead to abdominal pain, including stomach flu, gas, and acid reflux.

However, people with gluten intolerance often note experiencing abdominal pain frequently and without another obvious reason.

4. Fatigue

Fatigue is another symptom that people may find hard to identify, as it can have a lot of different causes, many of which are not related to any medical condition.

People with gluten intolerance may have persistent feelings of tiredness that impair daily functioning.

5. Nausea

People with gluten intolerance may also experience nausea, particularly after consuming a meal containing gluten. Nausea can have many causes, but if it often occurs after eating gluten, it can be a sign of gluten intolerance.

6. Headaches

Experiencing regular headaches is another symptom that can occur in people with gluten intolerance.

7. Other symptoms

People with gluten intolerance may experience several of these symptoms on a regular basis. It is also possible for other symptoms to occur with gluten intolerance, although they are less common.

According to a 2021 narrative review, other symptoms may include the following:

To diagnose a gluten intolerance, a doctor must rule out celiac disease and wheat allergy.

They may take a blood sample to analyze for antibodies that could indicate celiac disease or a wheat allergy. In some cases, other tests, such as an intestinal biopsy, may also be necessary.

Once a doctor has ruled out a more serious condition, it can still be difficult to confirm whether gluten intolerance is present, as there are no tests for this.

One method they may use to determine if gluten intolerance is present is to reduce or remove gluten from a person’s diet and monitor changes in symptoms.

It can help for a person to keep a food diary to record what foods they are consuming and what symptoms they are having.

Can gluten intolerance be misdiagnosed?

The symptoms of gluten intolerance can have a wide variety of causes.

Gluten intolerance is often mistaken for celiac disease, but they are separate conditions. Celiac disease is a severe autoimmune disease that can damage a person’s digestive system.

People also sometimes mistake gluten intolerance for a wheat allergy. A wheat allergy can be life threatening, as some symptoms impair breathing or cause a loss of consciousness, which is not the case with celiac disease or gluten intolerance.

People should seek immediate medical attention if they or someone else is experiencing difficulty breathing or staying conscious.

The symptoms of gluten intolerance are less severe than celiac disease or a wheat allergy, and people know much less about the condition.

Healthcare professionals may recommend that people with a gluten intolerance avoid any food with gluten in it, which includes any food that contains:

  • wheat and any derivatives of wheat, such as spelt
  • barley, including malt
  • rye
  • brewer’s yeast

This policy of elimination rules out many different types of foods and drinks. The most common foods and drinks containing gluten include:

  • pasta
  • bread and pastries
  • baked goods
  • noodles
  • crackers
  • cereals
  • pancakes, waffles, and crepes
  • biscuits
  • beers
  • malt beverages

Learn more about a gluten-free diet.

According to research in a 2023 review, gluten intolerance prevalence may range from 0.49–14.9% in adults.

The symptoms associated with this condition are widespread and have many potential causes. This means it can be easy to misidentify gluten intolerance.

Some people with gluten intolerance may benefit from completely excluding gluten from their diet. However, some people may still experience symptoms after doing this.

People can work with a healthcare professional to determine what type of diet and gluten restriction might work best to reduce their symptoms.

How to reduce gluten intake

While people with celiac disease must exclude gluten from their diet as soon as a doctor diagnoses the condition, many people with gluten intolerance slowly reduce the consumption of gluten rather than cutting it out straight away.

For example, a person may start by including one gluten-free meal daily before slowly adding more.

It may not be beneficial for everyone with gluten intolerance to cut gluten out of their diet entirely, as people’s symptoms will vary in severity.

Some people may be able to consume small amounts of gluten without experiencing any symptoms.

Below are some common questions about gluten intolerance.

What are the first signs of being gluten intolerant?

Symptoms of gluten intolerance may vary from person to person. However, common symptoms include:

  • abdominal pain
  • bloating
  • nausea
  • constipation or diarrhea

How does someone test themselves for gluten intolerance?

Doctors diagnose gluten intolerance by ruling out other conditions, such as celiac disease and a wheat allergy. People should speak with a healthcare professional if they believe they have a gluten intolerance.

How long after eating gluten do symptoms start?

Symptoms of a gluten intolerance may appear hours or days after consuming food or drinks that contain gluten.

How does someone know if they have celiac or a gluten intolerance?

Doctors will use a blood test to look for antibodies that indicate celiac disease. They may also carry out an intestinal biopsy.

They will usually only diagnose a gluten intolerance after ruling out celiac disease.

People who suspect they have a gluten intolerance should seek medical attention before making any dietary changes themselves.

If someone does not have celiac disease but feels better when they reduce their consumption of gluten, they must take care when making dietary changes.

Care is essential to avoid adverse health consequences, such as vitamin deficiencies.