Carbon 13 Lipids, Oral Absorption in Cystic Fibrosis

Cystic fibrosis (CF) is a lethal disease with a median survival age of 29 years in 1991. Increasedsurvival is associated with a more normal growth curve. However, growth failure continues to be aproblem; for example, approximately 40% of the CF individuals in 1990 were below the 5th percentilefor normal weight and height. The nutritional deficit in CF is associated with pancreatic insufficiencyand with the maldigestion of ingested fat. Pancreatic lipase supplements improve but frequently fail tocorrect the fat maldigestion. We have developed a novel, patented lipid-matrix composition(monoglycerides, fatty acids and lysophosphatidylcholine) which represents readily absorbable fatcalories. These non-toxic, lipid matrix (named LYM-X-SORB) provided the fat calories for sustainingnormal growth of rats from birth until 4 months of age. In this study the improved bioavailability of thislipid matrix in comparison to triglyceride-fat calories will be evaluated in fifteen CF and five normalsubjects of approximately 14 years. The bioavailability of these carbon 13-labeled fats will bedetermined by measuring expired labeled carbon dioxide over 8 hours which requires both absorptionand metabolism of the labeled fat. If a marked improvement in the bioavailability of the lipid matrix incomparison to triglycerides were observed in all CF individuals, a lipid-matrix food will be commerciallydeveloped for CF.