Gluten is a type of protein found in grains including wheat, barley, spelt and rye.

Celiac disease is a disorder in which eating gluten triggers an immune response in the body, causing inflammation and damage to the small intestine.

It’s estimated that celiac disease affects nearly 1% of the population in the United States (1).

Celiac disease is a serious condition that can cause a host of negative symptoms, including digestive issues and nutritional deficiencies.

These are the 9 most common signs and symptoms of celiac disease.

1. Diarrhea

Loose, watery stool is one of the first symptoms that many people experience before being diagnosed with celiac disease.

In one small study, 79% of celiac patients reported experiencing diarrhea prior to treatment. Following treatment, just 17% of patients continued to have chronic diarrhea (2).

Another study of 215 people noted that diarrhea was the most frequent symptom of untreated celiac disease.

For many patients, diarrhea was reduced within a few days of treatment, but the average time to fully resolve symptoms was four weeks (3).

However, keep in mind that there are many other possible causes of diarrhea, such as infection, other food intolerances or other intestinal issues.

Summary Diarrhea is one of the most common symptoms of celiac disease. Treatment can reduce and resolve diarrhea within a few days to a few weeks.

2. Bloating

Bloating is another common symptom that people with celiac disease experience.

Celiac disease can cause inflammation in the digestive tract, which may result in bloating as well as many other adverse digestive issues (4).

One study of 1,032 adults with celiac disease found that bloating was one of the most common symptoms. In fact, 73% of people reported feeling bloated prior to being diagnosed with the condition (5).

Another study showed that most patients with celiac disease experienced bloating. This symptom resolved effectively after they eliminated gluten from their diets (3).

Gluten has also been shown to cause digestive issues like bloating for people who don’t have celiac disease.

One study looked at 34 people without celiac disease who were experiencing digestive issues. These symptoms improved on a gluten-free diet. Participants then received either 16 grams of gluten or a placebo every day for six weeks.

Within just one week, those eating gluten experienced the worsening of several symptoms, including significantly more bloating than they had experienced beforehand (6).

Besides celiac disease, other common culprits behind bloating include constipation, bowel obstruction, chronic gas and digestive disorders.

Summary Patients with celiac disease often report bloating. Interestingly, gluten may also cause bloating for individuals without celiac disease.

3. Gas

Excess gas is a common digestive issue experienced by those with untreated celiac disease.

In one small study, gas was one of the most common symptoms caused by gluten consumption in those with celiac disease (7).

Similarly, a study looking at 96 adults with celiac disease in northern India reported that excess gas and bloating were present in 9.4% of cases (8).

However, keep in mind that there are many causes of gas. One study tested 150 people complaining of increased gas and found that only two tested positive for celiac disease (9).

Other, more common causes of gas include constipation, indigestion, swallowing air and conditions like lactose intolerance and irritable bowel syndrome (IBS).

Summary Studies show that gas is one of the most common symptoms of untreated celiac disease, though note that gas can be caused by many other conditions, as well.

4. Fatigue

Decreased energy levels and fatigue are prevalent in those with celiac disease.

One study of 51 celiac patients found that those who were untreated had significantly more severe fatigue and fatigue-related problems than those on a gluten-free diet (10).

Another study found that those with celiac disease were more likely to have sleep disorders, which could contribute to fatigue (11).

Additionally, untreated celiac disease can cause damage to the small intestine, resulting in vitamin and mineral deficiencies that may also lead to fatigue (12, 13).

Other potential causes of fatigue include infection, thyroid problems, depression and anemia.

Summary Fatigue is a common issue for those with celiac disease. Studies show that those with celiac disease are more likely to have sleep disorders and nutritional deficiencies, which may contribute to the problem.

5. Weight Loss

A sharp drop in weight and difficulty keeping weight on are often early signs of celiac disease.

This is because your body’s ability to absorb nutrients is impaired, which can potentially lead to malnutrition and weight loss.

One study of 112 participants with celiac disease found that weight loss affected 23% of patients and was one of the most common symptoms, following diarrhea, fatigue and stomach pain (14).

Another small study looking at elderly patients diagnosed with celiac disease noted that weight loss was one of the most common symptoms. Following treatment, not only were symptoms completely resolved, but participants actually gained an average of 17 pounds (7.75 kg) (15).

Similarly, another study looked at 42 children with celiac disease and found that introducing a gluten-free diet significantly increased body weight (16).

Unexplained weight loss could also be caused by conditions like diabetes, cancer, depression or thyroid problems.

Summary Many people with celiac disease experience unexplained weight loss. However, following a gluten-free diet typically helps people increase their body weight.

6. Iron-Deficiency Anemia

Celiac disease can impair nutrient absorption and may lead to iron-deficiency anemia, a condition caused by a lack of red blood cells in the body (17).

Symptoms of iron-deficiency anemia include fatigue, weakness, chest pain, headaches and dizziness.

One study looked at 34 children with celiac disease and found that nearly 15% had mild to moderate iron-deficiency anemia (18).

A study of 84 people with iron-deficiency anemia of an unknown origin found that 7% had celiac disease. After they went on a gluten-free diet, serum iron levels significantly increased (19).

Another study with 727 celiac patients reported that 23% were anemic. Additionally, those with anemia were twice as likely to have severe damage to the small intestine, as well as a low bone mass caused by celiac disease (20).

However, there are many other potential causes of iron-deficiency anemia, including a poor diet, the long-term use of pain relievers like aspirin, or blood loss through heavy menstrual bleeding or peptic ulcers.

Summary Celiac disease can impair nutrient absorption, which may lead to iron-deficiency anemia. Nevertheless, there are several other potential causes of iron-deficiency anemia, as well.

7. Constipation

While celiac disease may cause diarrhea in some people, it may cause constipation in others.

Celiac disease damages the intestinal villi, which are tiny, finger-like projections in the small intestine that are responsible for absorbing nutrients.

As food travels through the digestive tract, the intestinal villi are unable to fully absorb nutrients and may often absorb extra moisture from the stool instead. This leads to hardened stool that is difficult to pass, resulting in constipation (21).

However, even on a strict gluten-free diet, those with celiac disease may find it challenging to avoid constipation.

This is because a gluten-free diet cuts out many high-fiber foods like grains, which may result in decreased fiber intake and reduced stool frequency (22).

Physical inactivity, dehydration and a poor diet can cause constipation, as well.

Summary Celiac disease may cause the small intestine to absorb moisture from the stool, resulting in constipation. Additionally, a gluten-free diet may decrease fiber intake and can cause constipation.

8. Depression

Along with the many physical symptoms of celiac disease, psychological symptoms like depression are also prevalent.

One analysis of 29 studies found that depression was more common and severe in adults with celiac disease than in the general population (23).

Another small study with 48 participants found that those with celiac disease were more likely to have depressive symptoms than a healthy control group (24).

A study of 2,265 celiac patients found that 39% self-reported depression, but noted that sticking to a gluten-free diet long-term was associated with a reduced risk of depressive symptoms (25).

However, there are many other potential causes of depression, including fluctuations in hormone levels, stress, grief and even genetics.

Summary Celiac disease is associated with an increased risk of depression. However, following a long-term gluten-free diet may decrease the risk of depression.

9. Itchy Rash

Celiac disease may cause dermatitis herpetiformis, a type of itchy, blistering skin rash that can occur on the elbows, knees or buttocks.

Approximately 17% of those with celiac disease experience this rash and it is one of the telltale symptoms that lead to a diagnosis. It may also develop after diagnosis as a sign of poor adherence to treatment (26).

Interestingly enough, some people may develop this skin rash without the other digestive symptoms that typically occur with celiac disease. In fact, fewer than 10% of celiac patients who develop dermatitis herpetiformis experience digestive symptoms of celiac disease (27).

Other potential causes of an itchy skin rash besides celiac disease include eczema, psoriasis, dermatitis and hives.

Summary Celiac disease can cause a type of itchy skin rash. Many celiac patients who develop this rash don’t experience any gastrointestinal symptoms.

How to Manage Symptoms of Celiac Disease

Celiac disease is a lifelong condition that has no cure. However, people with this condition can manage their symptoms effectively by adhering to a strict gluten-free diet.

This means that any products containing wheat, barley, rye or spelt must be eliminated, including any foods that may have been cross-contaminated, such as oats, unless they’re labeled as gluten-free.

Foods to Avoid

Here are a few other foods you should avoid unless they’re specifically labeled as gluten-free:

  • Pasta
  • Bread
  • Cakes
  • Pies
  • Crackers
  • Cookies
  • Beer
  • Dressings
  • Sauces
  • Gravies

Foods to Eat

Fortunately, there are plenty of nutritious and naturally gluten-free foods out there. Cutting out processed foods, enjoying mostly whole foods and practicing label reading can make it much easier to follow a gluten-free diet.

Here are some foods that can be included in a healthy gluten-free diet:

  • Meat, poultry and seafood
  • Eggs
  • Dairy
  • Fruits
  • Gluten-free grains, such as quinoa, rice, buckwheat and millet
  • Vegetables
  • Legumes
  • Nuts
  • Healthy fats
  • Herbs and spices

If you suspect that you may have celiac disease, consult with your doctor to get tested for it and determine if a gluten-free diet is necessary for you.

Be sure not to begin a gluten-free diet until you are tested for celiac disease, as it may skew your test results.

Summary A gluten-free diet can help reduce symptoms of celiac disease. Products containing wheat, barley, rye and spelt should be eliminated and replaced with whole foods that are naturally gluten-free.

The Bottom Line

Celiac disease is a serious condition in which the immune system attacks the small intestine in response to eating gluten.

If left untreated, celiac disease can result in many adverse side effects, including digestive issues, nutritional deficiencies, weight loss and tiredness.

If you suspect you have celiac disease, speak with your doctor about getting tested. For those with celiac disease, following a gluten-free diet can help manage and reduce these symptoms.