Starch digestion in young children with cystic fibrosis measured using a 13C breath test

Abstract

The study was designed to evaluate a noninvasive breath test using naturally 13C-rich corn (maize) as substrate to provide quantitative information about the digestion of starch by children in health and disease. The variability of background I3C:I2C of young British children was investigated by collecting breath samples over 6 h from 17 healthy children, 6-35 mo old, and from seven children with cystic fibrosis, 25-48 mo old, in their homes. Background 13C enrichment was —26.6 and —25.4 d per mil in the healthy and cystic fibrosis groups, respectively (p < 0.01), and varied little during the day (SD = 0.4 d per mil). Eight healthy children and five with cystic fibrosis were given a test breakfast of corn starch cooked in milk with sugar. The cystic fibrosis group repeated the test with the addition of an enzyme supplement containing a-amy-lase. Subjects accepted variable amounts of starch (range 0.2-2.8 g/kg body wt). The percentage of ingested I3C recovered during the 6 h after the meal increased with age in the healthy children (range 15-53%). Three children with cystic fibrosis had negligible 13C recoveries, and the other two had lower recoveries than expected for their age. The addition of enzymes did not consistently improve 13C recovery. We conclude that the 13C breath test based on corn has potential for investigating starch digestion in young children. Initial results suggest that starch digestion is impaired in some children with cystic fibrosis and that enzyme supplements do not improve digestion consistently or completely. © 1992 International Pediatric Research Foundation, Inc.