August 2009 Issue

Optimizing Nutrition Status in Cystic Fibrosis          
By Rita E. Carey, MS, RD, CDE
Today’s Dietitian
Vol. 11 No. 8 P. 8

Cystic fibrosis (CF) is a congenital disorder that affects approximately 30,000 children and adults in the United States. A genetic defect inherited from both parents causes those with the disease to produce abnormal epithelial secretions throughout the body that impair lung function, digestive enzyme production, electrolyte balance, and nutrient absorption, among other effects. The disease’s pathophysiology increases the metabolic rate and caloric needs of both children and adults, often resulting in malnutrition.

For children with CF, optimizing nutrition can be especially challenging. High caloric requirements for growth and development, combined with behavioral issues surrounding food common to all kids, necessitates intervention from skilled practitioners who understand both behavioral management theory and nutrition therapy for chronic disease.

Living With CF
Fifty years ago, few children with CF lived to complete elementary school. Today, thanks to early detection and advanced respiratory and antibiotic treatments, many affected individuals can expect to live into their 40s—nearly twice the life span expected only 20 years ago. Most deaths from CF are due to chronic obstructive pulmonary disease and cardiorespiratory failure resulting from a lifetime of infections that damage the lungs. Daily respiratory treatment for people with CF centers on airway clearance and antibiotic therapy. Depending on the severity of the disease, percussive vests may be used one to four times daily to break up mucous so that it may be cleared from the lungs. Antibiotics are taken for acute infections, as well as prophylaxis, and are delivered as an aerosol via a nebulizer.

CF is also characterized by pancreatic insufficiency and subsequent nutrient malabsorption. The same mucous production that impairs the lungs inhibits the movement of pancreatic enzymes to the gut, resulting in steatorrhea and fat-soluble nutrient wasting. Patients with CF are instructed to take pancreatic digestive enzymes at every meal and snack to improve digestion and nutrient absorption. This may be particularly problematic for kids, who might easily forget or skip a dose if they are self-conscious about their special needs.

Long-term survival and overall pulmonary function is undoubtedly linked with nutrition status in both children and adults with CF.1,2 However, because energy needs are so high (120% to 150% above the Recommended Daily Allowance [RDA] for individuals without CF) and a variety of barriers to dietary adherence common, optimal nutrient intakes are actually achieved in only a small percentage of individuals. In fact, a number of studies done in the United States and United Kingdom since 1992 have demonstrated that only 11% to 23% of children with CF aged 7 months to 12 years meet the recommended 120% to 150% of the RDA for energy. It is important to note that most of the kids in these studies consumed about 100% of the RDA for energy for healthy children of the same age. Many were just unable to reach that higher, but critical, caloric goal.3,4

Overcoming Barriers
Satiety and food palatability issues can pose significant challenges to parents trying to encourage their children with CF to consume extra calories. Many of the foods recommended in the CF diet are energy dense and high in fat (the CF diet provides about 40% of calories from fat), and kids may not always accept them. Also, normal feelings of satiety typically occur 20 minutes into a meal for most individuals. Children generally do not choose to eat beyond normal satiety, which therefore may limit caloric intake at meals. Energy-dense snacks are strongly recommended to help add calories beyond the normal RDA, as kids are more likely to take in extra calories as a snack rather than consuming excess food at a meal.

Behavioral barriers to optimal nutrition are also a common problem. Lori Stark, PhD, a professor at the University of Cincinnati College of Medicine division of psychology, has conducted a number of observational and interventional studies over the last 20 years designed to identify and address these behavioral challenges. In a review article published in 2003 in the Proceedings of the Nutrition Society, Stark summarizes what she and her colleagues have observed in their studies: Delivery of nutrition recommendations without concurrent parental training in child behavior management is largely ineffective in meeting elevated CF dietary needs. Nutrition education combined with behavioral management training does, however, significantly improve nutrition status.

Stark has observed that when parents are given the knowledge that their child has elevated energy needs, they tend to increase their use of strategies they think will encourage kids to eat more. Coaxing, playing games, making threats, or making additional meals are common techniques used by parents of both healthy children and those with a chronic illness to encourage improved intake. Because parents of kids with CF are under great pressure to get their children to take even one extra bite at a meal, they tend to use these strategies more frequently than parents of healthy children. Unfortunately, such encouragement is ultimately ineffective. Behavioral theory suggests that kids repeat actions and behaviors that gain attention from their parents. Giving attention to noneating behaviors (eg, by coaxing or forcing a child to eat) may simply reinforce the noneating behavior the parents desperately want to change.

Stark and her colleagues created the intervention strategy Behavioral Intervention for Change Around Growth and Energy (Be In CHARGE!) to demonstrate the effectiveness of behavioral strategies combined with nutrition information for increasing the energy intake and growth rates of children with CF. Be In CHARGE! utilizes a group treatment approach that targets children aged 4 to 12, along with their parents.

During the intervention, children and parents attend separate group workshops. The parents learn child behavioral strategies one meal and one strategy at a time. They also receive nutrition education and learn to use tracking devices that record changes in child food intake and behaviors. Children are exposed to behavior management strategies in their own group setting through interactive games and lessons that stress the link between food and energy and energy and play. They also get their own tools to track their progress, and rewards are planned for various milestones. Behavioral strategies in this intervention concentrate on rewarding behaviors that the parents want to see more of and ignoring or otherwise creating boundaries or rules around behaviors they want their children to change (eg, dawdling at meals).

Children involved in the Be In CHARGE! program over the last 12 years have demonstrated in a number of studies an increase in calorie intake of 900 to 1,000 kcal/day and weight gains up to 1.42 kg over nine weeks compared with controls.

RD Support Is Vital
CF is a complex disease that requires rigid adherence to both medical and dietary prescriptions. Adherence to any medical regimen becomes more difficult as the duration of the treatment lengthens, and the more complicated the regimen, the tougher it is to follow. Because of this, dietitians skilled in engendering long-term behavioral and dietary change play an important role in supporting the health of individuals with CF.

— Rita E. Carey, MS, RD, CDE, is a clinical dietitian and diabetes educator at Yavapai Regional Medical Center and the Pendleton Wellness Center in Prescott, Ariz.


1. Gozdzik J, Cofta S, Piorunek T, Batura-Gabryel H, Kosicki J. Relationship between nutritional status and pulmonary function in adult cystic fibrosis patients. J Physiol Pharmacol. 2008;59(Suppl 6):253-260.

2. Zemel BS, Jawad AF, FitzSimmons S, Stallings VA. Longitudinal relationship among growth, nutritional status, and pulmonary functioning in children with cystic fibrosis: Analysis of the Cystic Fibrosis Foundation National CF Patient Registry. J Pediatr. 2000;137(3):374-380.

3. Tomezsko JL, Stallings VA, Scanlin TF. Dietary intake of healthy children with cystic fibrosis compared with normal control children. Pediatrics. 1992;90(4):547-553.

4. Powers SW, Patton SR, Byars KC, et al. Caloric intake and eating behavior in infants and toddlers with cystic fibrosis. Pediatrics. 2002;109(5):E75-5.