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 gastroesophageal reflux. Often parental reassurance and dietary management by feeding thickened formulas are the only therapeutic steps necessary. Adding fibers may interfere with the absorption of micronutrients.


METHODS
A continuous-flow dialysis in vitro method with a preliminary intraluminal digestive phase, modified to simulate the conditions of infants less than 6 months of age and children from 6 months of age on, was used to study the availability of calcium, iron, and zinc from thickened and nonthickened first-and second-age infant formulas. Pooled mature human milk was used as the reference standard. The elemental content of the samples and dialysate 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 absorptive processes. Availability of calcium, iron, and zinc from nonthickened first- and second-age infant formulas tends to be significantly better than in the corresponding products thickened with locust bean gum. Thickening infant formulas with pregelatinized rice starch, however, does not affect 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, and zinc seems to lower when infant formulas are thickened with indigestible carbohydrates, whereas it does not by adding digestible carbohydrates.
Bosscher
D
D
University of Antwerp, Department of Pharmaceutical Sciences, Belgium.
Van Caillie-Bertrand
M
M
Van Dyck
K
K
Robberecht
H
H
Van Cauwenbergh
R
R
Deelstra
H
H
D001682:Biological Availability; D002118:Calcium / Q000032:analysis / Q000493:pharmacokinetics; D003956:Dialysis; D004040:Dietary Carbohydrates; D004063:Digestion; D005764:Gastroesophageal Reflux / Q000178:diet therapy*; D006801:Humans; D007223:Infant; D007225:Infant Food / Q000032:analysis*; D007227:Infant Nutritional Physiological Phenomena; D007231:Infant, Newborn; D007501:Iron / Q000032:analysis / Q000493:pharmacokinetics; D018977:Micronutrients / Q000032:analysis* / Q000378:metabolism; D008895:Milk, Human / Q000737:chemistry; D015203:Reproducibility of Results; D013054:Spectrophotometry, Atomic; D015032:Zinc / Q000032:analysis / Q000493:pharmacokinetics
D004040:Dietary Carbohydrates; D018977:Micronutrients; D007501:Iron; D015032:Zinc; D002118:Calcium