Objective: Quantitative balance studies were performed to compare fat and calcium absorption in healthy, full term infants fed casein hydrolysate-based (CHF) and soy protein-based (SPF) infant formulas with or without palm olein (PO). Previous studies have reported that PO significantly reduced absorption of both fat and calcium in cow's milk-based formulas in which most of the calcium is inherent in the milk protein. In both SPF and CHF virtually all calcium is added as calcium salts.
Methods: Two randomized, blinded, crossover balance studies were conducted in normal term infants using a three-day home balance method. One study evaluated 10 infants fed commercially available CHF with or without PO, and the other study evaluated 12 infants fed commercially available SPF with or without PO. Fat and calcium absorption were determined based on the weight of formula intake, weight of stools, and measured calcium and fat in formula and stools.
Results: Fat and calcium intake did not differ between the groups fed CHF. However, infant's calcium and fat absorption was less, 41 +/- 6% (Mean +/- SEM) and 92.0 +/- 0.8%, respectively, when fed CHF with PO compared to 66 +/- 5% and 96.6 +/- 1.1%, respectively, when fed CHF without PO, (p < 0.01). For infants fed SPF, fat and calcium intake did not differ between the feeding groups. Mean calcium absorption was also significantly less when infants were fed SPF with PO, 22 +/- 3%, than when fed SPF with no PO, 37 +/- 4% (p < 0.05). Fat absorption did not differ between the two SPFs.
Conclusion: This study demonstrates that PO, as the predominant fat, is associated with significantly lower absorption of calcium from infant formulas in which calcium salts are the source of calcium. These findings corroborate previous reports of this negative effect of PO in cow milk-based infant formulas in which most of the calcium is a component of the cow milk protein source.