When someone with celiac disease eats gluten, the immune system responds by damaging the small intestine. This damage to the small intestine can lead to various symptoms, including digestive issues, such as bloating, gas, diarrhea, constipation, stomach pain, and more.
Some people have severe and persistent digestive symptoms, while others may only experience mild discomfort—or none at all. For many people with celiac disease, following a strict gluten-free diet can significantly improve symptoms over time. Understanding these symptoms can help individuals seek testing, manage their condition, and heal through a strict gluten-free diet.
It is important to note that digestive symptoms, although closely associated with celiac disease, are not necessary to get a diagnosis. In other words, not everyone with celiac disease experiences digestive symptoms.
Bloating
What it is: Bloating is a swollen, full, or tight feeling in the abdomen, often accompanied by discomfort or visible distension.
Why it happens in celiac disease:
A damaged intestine struggles to absorb nutrients. This malabsorption can cause excessive gas production, leading to bloating.
Inflammation in the gut results in fluid retention and slowed digestion.
Celiac disease can disrupt the balance of the gut microbiome, in other words the collection of trillions (yes, trillions!) of good bacteria in your gut, contributing to excess gas and bloating.
How it improves:
A strict gluten-free diet helps reduce inflammation and improve digestion.
Fiber and probiotics may aid digestion and reduce bloating—speak with your dietitian or doctor before changing your diet.
Constipation
What it is: Constipation is infrequent (fewer than three a week), difficult, or painful bowel movements. The stool that is passed during constipation is often dry and hard.
Why it happens in celiac disease:
Damaged villi in the small intestine slow digestion, leading to harder stools.
The intestine may absorb too much water, causing dry, difficult-to-pass stools.
Low fiber intake: Some people newly diagnosed with celiac disease reduce fiber unintentionally when switching to a gluten-free diet.
How it improves:
Eating a high-fiber gluten-free diet with plenty of fresh vegetables, fruits, nuts, and seeds.
Staying hydrated to support bowel movements by drinking at least 12 cups of water daily (for an adult).
Eating prunes or drinking coffee.
If your constipation doesn’t resolve on a gluten-free diet, consider talking with your doctor or dietitian about other options, such as a low FODMAP diet or laxatives.
Diarrhea
What it is: Diarrhea is loose, watery stool without form (can be fully liquid), sometimes accompanied by urgency and stomach pain.
Why it happens in celiac disease:
Intestinal damage prevents proper nutrient absorption, leading to undigested food and excess water in the stool.
Inflammation in the gut can speed up digestion, preventing proper stool formation.
Fat malabsorption (steatorrhea) can cause pale, greasy, foul-smelling stools.
How it improves:
A gluten-free diet allows the body to heal the small intestine, resulting in normal stool formation.
Eating low-fiber foods, such as rice, gluten-free pasta, potatoes, bananas, applesauce, and skinless vegetables.
Gas (Flatulence)
What it is: Excessive gas in the intestines can cause discomfort, bloating, and frequent flatulence (also known as farting).
Why it happens in celiac disease:
A damaged intestine struggles to break down food and absorb nutrients, leading to undigested food fermenting in the intestines and producing gas.
Dysbiosis (an imbalance in bacteria in your gut) can contribute to excessive gas production.
How it improves:
Following a gluten-free diet can significantly reduce gas over time.
Eating smaller meals with plenty of fiber can help ease digestion.
Chewing your food before swallowing can reduce gas—it means your gut has less work to do to break down the food!
Malabsorption and Nutrient Deficiencies
What it is: Malabsorption means that your body can’t take in the vitamins and minerals it needs to fuel the body.
Why it happens in celiac disease:
The immune system damages the small intestine. The damaged small intestine struggles to absorb nutrients like iron, B vitamins, vitamin D, and calcium.
Malabsorption of fat can lead to steatorrhea (pale, greasy stools).
Symptoms of malabsorption include:
Unintentional weight loss
Fatigue and weakness
Pale, foul-smelling stools
Hair loss
Bruising easily
Getting sick more often
In children, poor growth (short)
How it improves:
A strict gluten-free diet allows the intestine to heal and begin absorbing nutrients again.
A well-balanced diet full of fresh fruits, vegetables, meats, grains, and dairy provides plenty of vitamins and minerals for your body to absorb, once it’s begun to heal.
Your doctor and/or dietitian may recommend taking supplements such as iron, vitamin D, and B12.
Nausea
What it is: Nausea is a queasy, unsettled feeling in the stomach, sometimes leading to vomiting.
Why it happens in celiac disease:
Gluten exposure triggers an immune response, which can cause nausea.
Poor digestion and inflammation can slow stomach emptying.
How it improves:
A gluten-free diet can resolve chronic nausea.
Eating bland, easily digestible foods when symptoms flare up.
Drinking plenty of water. Tea with ginger or peppermint may also help.
Stomach Pain (Abdominal Pain and Cramping)
What it is: Pain or cramping in the abdomen, which may occur before, during, or after eating, or randomly throughout the day.
Why it happens in celiac disease:
Inflammation in the small intestine can cause generalized stomach pain.
A damaged intestine struggles to digest food, which can lead to cramping.
Excess gas or bloating caused by poor digestion can put pressure on the stomach and intestines.
How it improves:
Avoiding gluten completely.
Eating easily digestible food while the gut heals, such as rice, bananas, applesauce, eggs, and chicken.
Avoiding other food you may be sensitive to. For example, many people with celiac disease are also sensitive to dairy while their gut heals, so you may want to avoid lactose. However, you should speak with your doctor or a dietitian before significantly changing your diet.
Vomiting
What it is: Vomiting (also known as barfing or throwing up) is the forceful expulsion of stomach contents.
Why it happens in celiac disease:
Eating gluten can trigger vomiting in some people with celiac disease.
Gastroparesis, a condition where food stays in the stomach too long because of weak or slow stomach muscles, can occur in some people with celiac disease.
How it improves:
Avoiding gluten completely.
Eating small, easily digestible meals while the gut recovers.
Avoiding spicy, fatty, greasy, or salty foods that could irritate your gut.
In severe cases, consider talking with your doctor about anti-nausea or anti-vomiting medications if the vomiting does not go away, even on a strict, gluten-free diet. You may also want to get tested for other conditions that can cause vomiting, such as eosinophilic esophagitis (EOE), gastroesophageal reflux disease (GERD), Crohn’s disease, or irritable bowel syndrome (IBS).
When to See a Doctor
If you are experiencing persistent digestive symptoms, especially in combination with unexplained weight loss, fatigue, or nutrient deficiencies, consider getting tested for celiac disease. Note that you must be eating gluten to get tested for celiac disease—do not go gluten-free unless your doctor tells you to. Early diagnosis and strict adherence to a gluten-free diet can significantly improve symptoms and prevent long-term complications. Learn more about getting tested.
