Objective: To determine whether differences in tolerance and absorption of fat and nitrogen exist between a semi-elemental nutritional formula without enzyme replacement and a nonelemental formula with enzyme replacement.
Study design: Sixteen patients (eight girls and eight boys) with cystic fibrosis, 4 to 20 years of age (12+/-1.3, mean +/- SEM), who were pancreatic insufficient completed two 6-day regimens of nocturnal continuous enteral feedings offered in random order. Forty-four percent of the total daily energy was consumed as enteral tube feedings, and the remaining oral dietary intake remained constant throughout the study. Seventy-two-hour fecal collections from each study period were analyzed for total fat, long-chain fatty acids (LCFAs), medium-chain fatty acids (MCFAs), and nitrogen.
Results: Fat absorption was 80.2%+/-2.9% and 82.3%+/-3.1% (p = 0.58) for the semi-elemental and nonelemental formulas, respectively. Similarly, the coefficient of absorption of LCFAs was 69.5%+/-4.5% and 79.6%+/-3.4% (p = 0.30) for the semi-elemental and nonelemental formulas. Malabsorption of MCFAs contributed minimally to total fat malabsorption. There was no difference between formulas for MCFA or for nitrogen absorption, 83.7%+/-1.9% and 87.4%+/-1.4%, p = 0.48. All patients tolerated all feedings, and weight gained was 1.8+/-0.3 kg with no difference in weight gain between the trials.
Conclusion: A nonelemental formula, with enzyme replacement, is absorbed as well as a predigested formula in patients with CF who are pancreatic insufficient.