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Symptoms of Malnutrition with Cystic Fibrosis

Malnutrition is one of the most common problems caused by cystic fibrosis (CF). Gastrointestinal problems like malnutrition tend to occur in people with CF because the thick mucus generated by CF clogs the ducts (tubes) leading in and out of the pancreas, liver, and intestines. These blockages mean the pancreas cannot push enough enzymes into the intestines for food to be digested properly.

In fact, malnutrition and failure to thrive are so common in people with CF that it is one of the first symptoms reported in 28.1% of newly diagnosed patients.1 The good news is that malnutrition among people with CF is decreasing as doctors have learned to place more emphasis on nutrition than in past decades.2

Malabsorption leads to malnutrition

When the body can’t absorb nutrients, it is called malabsorption. Malabsorption means the body is not getting the nutrients it needs, which leads to malnutrition and trouble gaining or keeping on weight. In people with CF, malabsorption can be caused by in two ways:

  • Thick mucus stops the pancreas from sending enzymes into the intestines, which are needed for the body to absorb nutrients in food.
  • A defect in the intestines prevents nutrients from passing into the bloodstream.

Issues of malabsorption and malnutrition with cystic fibrosis

People with CF mostly have a problem breaking down and using proteins and fats rather than carbohydrates. Proteins are used in many processes in the body, including growth and cell repair for healing. Fats are calorie-rich sources for energy, growth and to process fat-soluble vitamins A, D, E, and K.

Delayed gastric emptying with cystic fibrosis

The problems of malabsorption are compounded by delayed gastric emptying, which is when the stomach empties more slowly than average. Delayed gastric emptying causes one to feel full more quickly and is quite common among people with CF.

Malnutrition is especially problematic for people with CF because they tend to burn more calories due to the extra work it takes for them to breath and fight infections. In fact, people with CF need up to twice the daily recommended calories of someone of the same age, height and weight.3

Symptoms of malnutrition

The symptoms of malnutrition in people with cystic fibrosis may be similar or overlap other signs of gastrointestinal problems. These symptoms include:

  • Poor weight gain or slow growth in children
  • Trouble keeping weight on in adults and children
  • Low energy, tiredness
  • Difficultly concentrating
  • Lack of appetite
  • Excessive gas
  • Frequent, large, greasy, bad-smelling stools
  • Abdominal pain or stomachache3,4

Treating malnutrition

It is important to avoid undernutrition or malnutrition in people with CF if possible because it makes it harder to stay healthy and to fight lung infections. That’s why doctors treat malnutrition so aggressively when someone has CF.

Pancreatic enzyme replacements (PERT)

Doctors prescribe pancreatic enzyme replacements (PERT) for the 90% of people with CF who have pancreatic insufficiency. Pancreatic enzymes help the person with CF break down their food so that enough energy and nutrition can be absorbed from the foods they eat.

Nutritional supplements

In addition to fat-soluble vitamins A, D, E, and K, B-complex vitamins, C vitamins, and probiotics, other nutritional supplements may also be prescribed. GERD can suppress the appetite so antacids, histamine H2 receptor antagonists, or proton pump inhibitors may be recommended to help ease symptoms and increase interest in food.2-5

Working with a dietician

A dietitian who specializes in helping people with cystic fibrosis can look closely at a person’s diet and help make recommendations to increase calorie and nutrition intake. People with CF are also usually encouraged to eat as much as they’d like of high-calorie, high-fat foods, along with plenty of nutrient-dense fruits and vegetables.3,4

Enteral Feeding

Enteral feeding (a feeding tube) may help those with CF who have a hard time consuming enough calories through regular meals and snacks. A feeding tube allows for overnight feeding, which helps boost nutritional intake and increases appetite.3

Research shows that maintaining a healthy weight helps reduce exacerbations and lung infections and improves quality of life. A body mass index (BMI) of 22 for women and 23 for men is recommended for those with CF. However, a BMI over 30 may put the person at risk of decreased lung function.3

Other GI complications

Other GI complications that people with cystic fibrosis develop are:

Written by: Jessica Johns Pool | Last reviewed: September 2019
  1. Cystic Fibrosis Foundation. Patient Registry Annual Data Report 2017. Available at: https://www.cff.org/Search.aspx?topic=230. Accessed 5/13/2019.
  2. Culhane, S. , George, C. , Pearo, B. and Spoede, E. (2013), Malnutrition in Cystic Fibrosis. Nutrition in Clinical Practice, 28: 676-683. doi:10.1177/0884533613507086.
  3. Dennett C. MNT in Cystic Fibrosis Care — What RDs Need to Know. Today's Dietitian. April 2017. Vol. 19, No. 4, p. 44.
  4. Cystic Fibrosis Foundation. Introduction to CF. Available at: https://www.cff.org/intro-to-CF.pdf. Accessed 5/13/2019.
  5. Chase P, et al. Cystic fibrosis and malnutrition. J Pediatr, 1979;95(3):337-347. https://doi.org/10.1016/S0022-3476(79)80504-1.