Celiac disease is a serious condition that can cause many negative symptoms, including digestion problems and nutritional deficiencies.

Eating gluten triggers off an immune response in the body of those with celiac disease, which causes damage and inflammation in the small intestine. Gluten is a type of protein found in grains, which include wheat, barley, rye and spelt. Sufferers of celiac disease can show different symptoms, the most common ones being the 9 in this list.

1. Diarrhea

Many people suffer with loose, watery stools before they are diagnosed with celiac disease. In one study, 79% of celiac patients said they had diarrhea before treatment. After the treatment, only 17% of patients continued to have chronic diarrhea.

Another study noted that diarrhea is the most frequent symptom of untreated celiac disease. After treatment, the diarrhea was reduced within a few days for many patients, but the average time for the symptoms to fully disappear was four weeks.

There are other causes of diarrhea, such as infection, intestinal issues or other food intolerances, so keep this in mind before jumping to the conclusion that you definitely have celiac disease.

2. Bloating

Celiac disease can inflame the digestive tract, which can result in bloating as well as other digestive problems.

A study of 1,032 adults with celiac disease showed that bloating was one of the most common symptoms, and 73% of people reported feeling bloated before being diagnosed with the disease. The symptoms resolved effectively after they removed gluten from their diets.

Gluten can also cause digestive problems such as bloating for those who don’t have celiac disease. One study investigated 34 people without celiac disease who were suffering from digestive issues. They were put on a gluten-free diet and their symptoms improved. They then received either 16 grams of gluten or a placebo per day for six weeks, and within only one week those who had the gluten experienced an increase of several symptoms, including bloating.

Other symptoms of bloating include constipation, digestive disorders, bowel obstruction or chronic gas.

3. Gas

Those suffering with untreated celiac disease often suffer from excess gas. One small study showed that gas was one of the most common symptoms caused by gluten consumption in those with celiac disease.

There are, however, other common causes of gas, such as constipation, indigestion, air swallowing and conditions like lactose intolerance and irritable bowel syndrome.

Another study tested 150 people who complained of excess gas, and found that only two of them tested positive for celiac disease. It’s worth looking into other possible causes of gas first before assuming that you have celiac disease.

4. Tiredness

Fatigue and decreased energy levels are common in those who suffer from celiac disease.

A study of 51 celiac patients found that those who hadn’t been treated had significantly more fatigue and other related problems than those who ate a gluten-free diet.

Untreated celiac disease can also cause damage to the small intestine, which could result in fatigue because of vitamin and mineral deficiencies.

Other symptoms of excessive tiredness could include infection, depression, anaemia and thyroid problems.

5. Weight Loss

If you lose weight quickly for no reason, or have trouble keeping weight on, you may have celiac disease. This is because your body’s ability to absorb nutrients is impaired, and could lead to weight loss and malnutrition.

One study, which looked at elderly patients who were diagnosed with celiac disease, showed that weight loss was one of the most common symptoms. After treatment, the symptoms were completely resolved, and the participants actually gained an average of 17 pounds.

However, there are other conditions that can cause unexplained weight loss, including diabetes, depression, cancer or thyroid problems.

6. Iron-Deficiency Anemia

Celiac disease could lead to iron-deficiency anemia because it impairs nutrient absorption. Symptoms of iron-deficiency anemia include weakness, chest pain, fatigue, headaches and dizziness.

A study of 727 celiac patients reported that 23% of them were anemic. Those with anemia were found to be twice as likely to have suffered severe damage to the small intestine, as well as low bone mass caused by celiac disease.

Other causes of iron-deficiency anemia include a poor diet, peptic ulcers, long-term use of painkillers such as aspirin, and also blood loss through heavy menstrual bleeding.

7. Constipation

Celiac disease causes diarrhea in some people, yet in others it can cause constipation.

Celiac disease damages the intestinal villi, which exist in the small intestines and are responsible for absorbing nutrients. As food moves through the digestive tract, the damaged villi are unable to fully absorb nutrients and may instead absorb extra moisture from the stool instead. This leads to hardened stools and constipation.

Even switching to a gluten-free diet may not relive the constipation problem, and this is because a gluten-free diet cuts out a lot of high-fiber foods such as grains, which may decrease the overall fiber intake.

Keeping hydrated, eating a healthy diet and physical exercise are ways to help reduce constipation.

8. Depression

Sufferers of celiac disease often suffer from psychological symptoms, such as depression, as well as physical ones.

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

There are other causes of depression, such as stress, grief, fluctuating hormones and genetics.

9. Itchy Rash

Celiac disease can cause dermatitis herpetiformis, which is a type of itchy, blistering skin rash that occurs mainly on the elbows, knees or buttocks.

Around 17% of those diagnosed with celiac disease get this rash, and it is one of the telltale symptoms that lead to a diagnosis. Some people may get the skin rash without the digestive symptoms that typically occur with celiac disease, and fewer than 10% of celiac patients who develop this skin condition experience any digestive symptoms of celiac disease.