Cystic fibrosis (CF) is caused by mutations in the CFTR gene, which encodes a protein involved in the transport of salts in and out of cells. The resulting defects in the transport of salts across cells lead to the buildup of thick and sticky mucus in various organs, affecting their function.
Patients’ airways and lungs are typically affected by this abnormal mucus accumulation, and the disease can also cause serious problems with the digestive system.
As the sticky mucus builds in digestive tract organs, it can cause intestinal blockages in CF patients, especially in newborns. This condition is called meconium ileus (“meconium” is the first stool a newborn has, and “ileus” is a kind of intestinal blockage or obstruction).
Thick CF mucus can also block the tubes or ducts within the pancreas, an organ responsible for producing the hormone insulin, which works in the bloodstream to remove glucose (sugar) and transport it to cells for energy. Patients whose pancreas does not produce enough insulin can develop insulin deficiency, or they can become insulin-resistant. In either case, they are at risk of developing CF-related diabetes.
The pancreas also makes digestive enzymes that help break down food. In CF, thick mucus can prevent the pancreas from properly releasing these enzymes into the intestines. Without enough digestive enzymes, CF patients may have difficulty breaking down food and absorbing it properly, especially fats and proteins. This can cause patients not to absorb enough nutrients and calories from their food, and can also lead to bouts of pain, constipation, or floating, greasy stools. Many CF patients, especially children, have poor weight gain and growth because they are unable to get enough nutrients from their food.
As the disease progresses, other digestive problems may occur, including:
- Pancreatitis, where the pancreas becomes inflamed, and can be very painful
- Rectal prolapse, where frequent coughing or difficult bowel movements causes rectal tissue to move outside of the rectum; it may require surgery to treat
- Liver disease, caused by impaired secretion and flow of bile, as well as inflamed ducts
- Diabetes, caused by insufficient insulin production or insulin-resistance
- Gallstones, or hard deposits of digestive fluid in the gallbladder, which may be painful and cause blockages
- Osteoporosis or brittle and weak bones, raising the risk of fractures. Difficulties patients have in absorbing necessary nutrition from their diet can affect their ability to maintain strong bones.
Treating digestive symptoms
A nutritionist can help people with CF and their caregivers ensure that the patient is getting the nutrients they need from their food. A good nutrition plan can also help patients stay active and strong, and better able to resist infections.
In addition to a healthy diet, patients may need:
- Oral pancreatic enzymes to help digest fats and proteins, and absorb more vitamins. This approach is called pancreatic enzyme replacement therapy.
- Medications to reduce stomach acid, helping the pancreatic enzymes to work better
- Supplements of vitamins A, D, E, and K to replace the fat-soluble vitamins that CF patients have trouble absorbing
- High-calorie shakes to provide extra nutrients
- A high-salt diet or salt supplements to help with growth or during hot-weather months, as people with CF lose considerable salt when they sweat
- A night-time feeding tube to help provide more calories while the patient is sleeping. Other options are tubes surgically connected to a port in the patient’s stomach or directly into the small intestine.
- Enemas, mucus-thinning medications, and/or surgeries to treat intestinal blockages
- Probiotics and prebiotics to promote the growth of healthy bacteria in the gut.
Last updated: Aug. 10, 2021
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