Displacement of human milk during fortification: An experimental study

Background: This study quantified the displacement of human milk by commercial human milk fortifiers (HMFs) and infant formulas. Methods: Commercial liquid HMFs and powder infant formulas were added to pasteurized pooled donor human milk in triplicate, stirred, and weighed. The difference in weight between unfortified and fortified human milk at 22, 24, 26, 27, 28, and 30 kcal/ounce was calculated. Results: The displacement of human milk by liquid HMFs and powder infant formulas and powder HMF was highly associated with energy density. A human milk–derived HMF displaced significantly more human milk when compared with bovine milk–derived HMFs at equivalent energy densities. Similarly, powder infant formulas displaced less human milk when compared with a powder HMF, and the addition of hydrolyzed powder infant formulas resulted in less human milk displacement when compared with nonhydrolyzed powder infant formulas. Conclusions: The displacement of human milk by commercial liquid HMFs and infant formulas must be considered when selecting a fortifying strategy.