GLYCEMIC RESPONSE TO DIETARY-SUPPLEMENTS IN CYSTIC-FIBROSIS IS DEPENDENT ON THE CARBOHYDRATE CONTENT OF THE FORMULA

Background: Enteral formula feedings are frequently prescribed to cyst ic fibrosis (CF) patients to boost caloric intake. A substantial numbe r of these patients are glucose intolerant and have severe respiratory compromise. Methods: To determine the effect of the carbohydrate cont ent on glucose tolerance and respiratory function in glucose-intoleran t CF patients with poor lung function, we examined the response to bol us feedings of five dietary supplements: a high-fat formula developed in our Clinical Research Center (CRC), Pulmocare, a high-carbohydrate formula developed in our CRC, Ensure Plus, and sugar-free Scandishake. Results: Glucose excursion in response to the formulas with the lowes t carbohydrate content was significantly less than that found in respo nse to formulas with higher carbohydrate content. Insulin levels were also markedly lower in response to the low-carbohydrate high-fat formu las. Glucose excursion, expressed as a percent of the response to the CRC high-fat formula, was 111% +/- 12% for Pulmocare (p = NS), 202% +/ - 34% for Ensure Plus (p < .01), 227% +/- 37% for CRC high carbohydrat e (p = .001), and 357% +/- 33% for sugar-free Scandishake (p < .001). CO2 production, O-2, consumption, minute ventilation, and respiratory rate increased modestly but not significantly in response to all formu las. No significant differences were found between the formulas in reg ards to these parameters. There were no subjective complaints of dyspn ea during any of the five studies. Conclusion: The carbohydrate conten t of liquid dietary supplements appears to be an important determinant of hyperglycemia in glucose-intolerant adult CF patients.