Effect of enteral IGF-1 supplementation on feeding tolerance, growth, and gut permeability in enterally fed premature neonates

Objectives: The gastrointestinal tract of the premature newborn functions suboptimally with regard to digestion, absorption, and feeding tolerance. Human milk contains trophic factors, such as insulin-like growth factor-1 (IGF-1), that are believed to stimulate gut growth and function. The objective of this double blind, randomized, controlled trial was to assess the effects of enteral IGF-1 supplementation on whole body growth measured by weight gain (in grams per kilogram per day), days to regain birth weight, and anthropometrical characteristics, and gut maturation and permeability (measured by sugar absorption tests). Patients and Methods: The study included 60 premature infants (birth weight 750-1250 g) during the first month of life. Patients received either standard infant formula or standard infant formula supplemented with IGF-1 in a concentration twice that of human colostrum (10 mu g/100 mL of formula). Primary endpoints were days to full enteral feeding, days to regain birth weight, and growth rate. Sugar absorption tests were performed weekly to assess the secondary endpoints gut permeability and maturation. Results: None of the primary endpoints differed to statistical significance between groups at any point. However, gut permeability was significantly lower in the IGF-1 supplement group on day 14 compared with the control group. At day 21, lactulose/mannitol excretion ratios were (again) comparable between the groups. Conclusions: Although gut permeability showed a faster decrease in the IGF-1 supplement group, our data do not support IGF-1 supplementation to infant formula.