Thickening infant formula with digestible and indigestible carbohydrate: Availability of calcium, iron, and zinc in vitro

Background: Regurgitation is common in infants and is usually due to gastro esophageal reflux. Often parental reassurance and dietary management by fee ding thickened formulas are the only therapeutic steps necessary. Adding fi bers may interfere with the absorption of micronutrients. Methods: A continuous-flow dialysis in vitro method with a preliminary intr aluminal digestive phase, modified to simulate the conditions of infants le ss than 6 months of age and children from 6 months of age on, was used to s tudy the availability of calcium, iron, and zinc from thickened and nonthic kened first- and second-age infant formulas. Pooled mature human milk was u sed as the reference standard. The elemental content of the samples and dia lysate fractions of calcium, iron, and zinc after digestion was determined by atomic absorption spectrometry. Results: In human milk, calcium, iron, and zinc were highly available for a bsorptive processes. Availability of calcium, iron, and zinc from nonthicke ned first- and second-age infant formulas tends to be significantly better than in the corresponding products thickened with locust bean gum. Thickeni ng infant formulas with pregelatinized rice starch, however, does not affec t the availability of calcium, iron, and zinc. Conclusions: It appears that human milk provides optimal conditions for the availability of calcium, iron, and zinc. Availability of calcium, iron, an d zinc seems to lower when infant formulas are thickened with indigestible carbohydrates, whereas it does not by adding digestible carbohydrates.