Digestive system and cystic fibrosis

The pancreas creates enzymes, which are important chemicals that break down fats, proteins and carbohydrates in your food. This is important for releasing the nutrients that your body uses to make energy.

In digestion in people with CF, the small tubes that transport these enzymes out of the pancreas become blocked with mucus. The enzymes build up in the pancreas instead of reaching the digestive system (specifically, the lumen of the gut), causing the pancreas to become inflamed. As a result, people with CF have to take supplements to replace these enzymes with their meals to help digest their food. A person whose pancreas is affected in this way is suffering from ‘pancreatic insufficiency’. 

Problems with the pancreas can also cause CF-related diabetes (CFRD), which affects around a third of people with cystic fibrosis.

Find out more about CFRD

Because of these difficulties digesting fat, some people with cystic fibrosis require more fatty foods and a higher daily calorie intake than those without the condition, particularly if they are fighting an infection. People with cystic fibrosis also often experience digestive symptoms such as:

• greasy and bulky stools
• frequent and/or difficult bowel movements
• constipation
• nausea
• swollen abdomen
• loss of appetite

Medication can help compensate for the failure of the pancreas, such as digestive enzymes (Creon®) that most people with cystic fibrosis take with each meal to help digest food.

Find out more about nutrition in cystic fibrosis

There is some research to suggest that there may be an increased risk of bowel (or colorectal) cancer in people with cystic fibrosis. Find out more about bowel cancer, the risks in people with CF and how it is screened for.

Find out more about bowel cancer

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One in every ten babies born with cystic fibrosis develops a bowel obstruction called meconium ileus at birth or within the first few days of life. In these cases, the meconium (a thick black material present in the bowels of all new born babies) is so thick that it blocks the bowel instead of passing through.

Babies with meconium ileus often need an urgent operation to relieve and bypass the blockage.

Previously known as meconium ileus equivalent (MIE), DIOS is a condition that is unique to cystic fibrosis. DIOS causes blockages in the small bowel, causing symptoms such as stomach pain, bloating, nausea and weight loss. In most cases DIOS can be controlled with medication.

Gastro oesophageal reflux disease (GORD) occurs when acid and non-acid contents of the stomach move in the wrong direction and go back into the oesophagus (gullet). This can cause burning of the oesophagus or ‘heart burn’ and is thought to provoke coughing and possibly contribute to lung damage.

GORD is more common in CF because of excessive coughing, obstructive lung disease, delayed emptying of the stomach, some people eating a high-fat diet, a lax valve at the bottom of the oesophagus and other CF-specific complications.

Medicines that reduce or neutralise acid in the stomach, or surgery to strengthen the sphincter or valve at the bottom of the oesophagus, may be advised to help treat GORD. It is very common to have treatment to reduce GORD before a lung transplant as reflux and aspiration may increase the risk of lung rejection post-transplant.

The Trust-funded GRAMPUS-CF Strategic Research Centre aims to link the specific gut symptoms people with CF experience to what changes are taking place within their intestines. By increasing understanding of the cause of the symptoms, the researchers hope that this could lead to more tailored treatments in the future.