Development Of An Innovative Panel of Methods To Measure Intestinal Macronutrient Digestion, Absorption, and Function

Malnutrition is a significant problem in children and adults with Cystic fibrosis (CF). An impaired intestinal digestion and absorption capacity is one of the main factors responsible for the malnutrition in CF. This impairment starts early in life, leading to malnutrition, muscle weakness, impaired immune and lung function associated with poor prognosis. As low BMI and body weight is strongly associated with morbidity and mortality, a reduction in weight loss in CF and its manifestations would save the healthcare system substantially per year. Simple methods to measure the digested portions and utilization of nutrients and the effectiveness of pancreatic enzyme preparations and medications in CF are not available. Developing a panel of methods to accurately measure gut digestion, absorption and function will lead to studies optimizing nutritional regimen and pancreatic enzyme replacement therapy in CF. Furthermore, it will provide detailed insight in the disease and age related mechanisms of gut dysfunction in CF. Finally, it will provide required information that will lead to implement new strategies to improve gut health in order to enhance nutritional status, quality of life and survival.

The hypothesis is that intestinal macronutrient digestion, absorption and function in CF can be quantified by an innovative panel of methods using stable isotopes. With this panel of methods, information can be obtained on the effect of disease progression on lipid, protein and glucose digestion and absorption and on gut function in CF as well as in other diseases and conditions characterized by a compromised gut. Furthermore, the optimal nutritional regimen and pancreatic enzyme therapy if applicable can be evaluated in these diseases. In the present study the investigators will study: 1. Pediatric patients with CF at Arkansas Children's Hospital; 2. Adult patients with CF at University of Arkansas for Medical Sciences. 3. Healthy control subjects. Diagnosis of CF is made based on universal diagnostic criteria. All CF patients are characterized by abnormal lipid digestion based on clinical and or laboratory (72 hour fat analysis or fecal elastase measurement) diagnosis, and requiring pancreatic enzyme replacement therapy, and no presence of unstable metabolic diseases. Additional criteria for the CF pediatric inpatients are: admitted to ACH for treatment of exacerbations of CF disease, clinically stable. The CF outpatients are stable outpatients with pancreatic insufficiency.