Cystic fibrosis is an inherited condition that can cause mucus buildup in the pancreas. This can interfere with the typical pancreas function and cause problems during food digestion. It can also cause changes in stools, or “poop.”

The mucus that cystic fibrosis can produce in the pancreas can prevent the regular release of enzymes in the gut. This can interfere with digestion and make it more difficult for the body to absorb nutrients from food. This means people with cystic fibrosis may need dietary changes to prevent malnutrition.

This article looks at how cystic fibrosis affects the digestive system and the stools, what treatments are available, and when people should contact a doctor.

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People with cystic fibrosis may have more difficulty digesting food as the sticky mucus that the pancreas produces may interfere with digestion. This can also cause blockages in the digestive tract.

About 90% of people with cystic fibrosis have mucus blocking the pancreatic duct. This may prevent the release of enzymes from the pancreas necessary for digesting food.

The pancreas also produces a substance called bicarbonate to neutralize the acidity of digested food coming from the stomach. However, people with cystic fibrosis do not produce enough bicarbonate to help with this process.

For these reasons, those with the condition may experience some gastrointestinal symptoms, including:

Learn more about the symptoms of cystic fibrosis.

Researchers believe cystic fibrosis may affect the digestive process and cause some stool changes.

People with the condition may produce large, greasy stools that may float due to the high quantity of gas they may contain.

Cystic fibrosis may also lead to blockages in the bowels, resulting in constipation.

The disrupted digestive process may also cause diarrhea.

Learn more about stool types.

To prevent the production of greasy stools, people can start a treatment plan to improve the effect cystic fibrosis may have on digestion.

Those with the condition may not produce enough enzymes in their pancreas, meaning the pancreas may not absorb enough nutrients. These may include:

Doctors may recommend some dietary and lifestyle changes that may help prevent the production of greasy stools, including:

  • avoiding smoking, if applicable
  • exercising regularly
  • keeping hydrated
  • eating a nutritious diet that may involve taking in extra calories
  • taking fat-soluble vitamin supplements
  • taking zinc and iron supplements

Doctors may also recommend undergoing pancreatic enzyme replacement therapy (PERT) to improve digestion and the lack of enzyme production from the pancreas.

About 80–90% of people with cystic fibrosis require pancreatic PERT. Doctors may recommend this treatment to replace enzymes the pancreas typically produces, but that cannot reach the digestive tract due to the mucus blockage relating to cystic fibrosis.

People with cystic fibrosis should also attend regular checkup appointments to monitor the occurrence of any deficiencies or signs of malabsorption of food.

People with cystic fibrosis should contact their doctor if they regularly or persistently experience any of the following:

People should also contact their doctor if they have any concerns about their current treatment plan.

People with cystic fibrosis may develop distal intestinal obstruction syndrome (DIOS). This is a possible complication of cystic fibrosis.

DIOS occurs when a buildup of feces produces a mass that partially or completely blocks the intestine.

People with DIOS may experience symptoms, such as:

  • severe abdominal pain
  • swollen stomach
  • vomiting

In some cases, if doctors cannot relieve the buildup of feces with medications, people may need to undergo surgery to remove the blockage.

The pancreas produces enzymes necessary for digestion. Cystic fibrosis can result in a buildup of mucus in the pancreas that may prevent the regular function of this organ. This may cause difficulties during the digestion of food and the absorption of nutrients.

People with cystic fibrosis symptoms may experience abdominal pain, gas, and cramping. Constipation or diarrhea may also occur, while stools can also appear greasy and bulky.

People with cystic fibrosis may need to make some dietary changes, take vitamin supplements, and undergo PERT treatment to improve the lack of enzymes that may occur due to the atypical function of the pancreas.