The 13 most common signs of gluten intolerance

Adda Bjarnadottir, of, examines some tell-tale signs that may give you an early inkling of gluten intolerance…

Gluten intolerance is a fairly common problem. It is characterised by adverse reactions to gluten, a protein found in wheat, barley and rye. Coeliac disease is the most severe form of gluten intolerance. It is an autoimmune disease that affects about 1% of the population and can lead to damage to the
digestive system.

However, 0.5-13% of people may also have non-coeliac gluten sensitivity, a milder form of gluten intolerance that can still cause problems. Both forms of gluten intolerance can cause widespread symptoms, many of which have nothing to do with digestion.

Here are the 13 main signs and symptoms of gluten intolerance…


Bloating is when you feel as if your belly is swollen or full of gas after you’ve eaten.

Although bloating is common and can have many explanations, it may also be a sign of gluten intolerance. In fact, feeling bloated is one of the most common complaints of people who are sensitive or intolerant to gluten.

2 Diarrhoea, constipation and smelly faeces

Occasionally getting diarrhoea and constipation is normal, but it may be a cause for concern if it happens regularly. These also happen to be a common symptom of gluten intolerance.

Individuals with coeliac disease experience inflammation in the gut after eating gluten. This damages the gut lining and leads to poor nutrient absorption, resulting in significant digestive discomfort and frequent diarrhoea or constipation.

However, gluten may also cause digestive symptoms in some people who don’t have coeliac disease. More than 50% of gluten-sensitive individuals regularly experience diarrhoea, while about 25% experience constipation.

Furthermore, individuals with coeliac disease may experience pale and foul-smelling faeces due to poor nutrient absorption. Frequent diarrhoea can cause some major health concerns, such as loss of electrolytes, dehydration and fatigue.

Abdominal pain

Abdominal pain is very common and can have numerous explanations. However, it is also the single most common symptom of a gluten intolerance. Up to 83% of those with gluten intolerance experience abdominal pain and discomfort after eating gluten.


Many people experience headaches or migraines once in a while. Studies have shown that gluten-intolerant individuals may be more prone to migraines than others.

5  Feeling tired

Fatigue is common and usually not linked to any disease. However, if you constantly feel very tired, then you should explore the possibility of an underlying cause. Gluten-intolerant individuals are very prone to fatigue and tiredness, especially after eating foods that contain gluten.

Studies have shown that 60-82% of gluten-intolerant individuals commonly experience tiredness and fatigue. Furthermore, gluten intolerance can also cause iron-deficiency anemia, which in turn will cause more tiredness and lack of energy.

Skin problems

Gluten intolerance can also affect your skin. A blistering skin condition called dermatitis herpetiformis is the skin manifestation of coeliac disease.

Everyone who has the disease is sensitive to gluten, but less than 10% of patients experience digestive symptoms that indicate coeliac disease. Furthermore, several other skin diseases have shown improvement while on a gluten-free diet, including psoriasis, alopecia areata and chronic urticaria.


Depression affects about 6% of adults each year.

People with digestive issues seem to be more prone to both anxiety and depression, compared to healthy individuals. This is especially common among people who have coeliac disease.

Unexplained weight loss

An unexpected weight change is often a cause for concern. Although it can stem from various reasons, unexplained weight loss is a common side effect of undiagnosed coeliac disease.

In one study in coeliac disease patients, two-thirds had lost weight in the six months leading up to their diagnosis. The weight loss may be explained by a variety of digestive symptoms, coupled with poor nutrient absorption.

Iron-deficiency anaemia

Iron-deficiency anaemia is the most common nutrient deficiency in the world. Iron deficiency causes symptoms such as low blood volume, fatigue, shortness of breath, dizziness, headaches, pale skin and weakness.

In coeliac disease, nutrient absorption in the large intestine is impaired, resulting in a reduced amount of iron being absorbed from food. Iron deficiency anemia may be among the first symptoms of coeliac disease that your doctor notices.

10 Anxiety

Anxiety may affect 3-30% of people worldwide. It involves feelings of worry, nervousness, unease and agitation. Furthermore, it often goes hand-in-hand with depression.

Individuals with gluten intolerance seem to be more prone to anxiety and panic disorders than those without. Additionally, a study showed that up to 40% of individuals with self-reported gluten sensitivity stated that they regularly experienced anxiety.

11 Joint and muscle pain

There are numerous reasons why people experience joint and muscle pain. Some think those with coeliac disease have a genetically determined over-sensitive or over-excitable nervous system. Therefore, they may have a lower threshold to activate sensory neurons that cause pain in muscles and joints.

Moreover, gluten exposure may cause inflammation in gluten-sensitive individuals. The inflammation may result in widespread pain, including in joints
and muscles.

12 Leg or arm numbness

Another surprising symptom of gluten intolerance is neuropathy, which involves numbness or tingling in the arms and legs.

This condition is common in individuals with diabetes and vitamin B12 deficiency. It can also be caused by toxicity and alcohol consumption. However, individuals with coeliac disease and gluten sensitivity seem to be at a higher risk of experiencing arm and leg numbness, compared to healthy control groups. While the exact cause is not known, some have linked this symptom to the presence of certain antibodies related to gluten intolerance.

13 Brain fog

‘Brain fog’ refers to the feeling of being unable to think clearly. People have described it as being forgetful, having difficulty thinking, feeling cloudy and having mental fatigue.

Having a ‘foggy mind’ is a common symptom of gluten intolerance, affecting up to 40% of individuals. This symptom may be caused by a reaction to certain antibodies in gluten, but the exact reason is unknown.

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