Cystic fibrosis: nutrition

Area of Science:

• Pediatrics
• Pulmonology
• Nutritional Science

Background:

• Renewed interest exists in understanding undernutrition and growth failure in cystic fibrosis (CF).
• Undernutrition in CF is now understood as a consequence of unfavorable energy balance, not an intrinsic disease feature.
• A direct correlation is observed between the severity of undernutrition and the extent of pulmonary disease, impacting overall prognosis.

Purpose of the Study:

• To examine the multifaceted causes of undernutrition and growth failure in cystic fibrosis.
• To elucidate the relationship between energy balance, nutritional status, and pulmonary disease severity in CF patients.

Main Methods:

• Review of current understanding of energy balance in cystic fibrosis.
• Analysis of factors contributing to negative energy balance: maldigestion, reduced intake (anorexia, diet, symptoms), and increased expenditure.
• Evaluation of the impact of nutritional status on pulmonary function and prognosis.

Main Results:

• Energy imbalance in CF arises from increased nutrient maldigestion, reduced energy intake (due to anorexia, respiratory disease, abdominal symptoms, depression), and elevated energy expenditure in advanced lung disease.
• Most CF patients can compensate for these factors with adequate energy intake, maintaining normal growth and nutritional status.
• A subset of older patients with advanced lung disease experience an energy deficit due to increased expenditure, leading to undernutrition and potential decline in lung function.

Conclusions:

• Undernutrition in cystic fibrosis is primarily driven by energy imbalance, influenced by maldigestion, intake, and expenditure.
• Maintaining adequate energy intake is key for most CF patients to achieve normal growth and nutritional status.
• In advanced CF lung disease, nutritional support may be necessary to restore energy balance and prevent further deterioration.