Effect of Added Calcium, Phosphorus, and Infant Formula on Calcium and Phosphorus Dialyzability in Preterm Donor Human Milk

ABSTRACT Objectives: We studied the effect of preparing donor human milk (DHM) with commonly used nutritional additives on the dialyzability of calcium and phosphate. We hypothesized that the additives to DHM would decrease the dialyzability of calcium and phosphate when prepared according to hospital protocols. Methods: An in vitro system simulating premature infant digestion was developed to measure dialyzability of calcium and phosphate in DHM. Dialyzable calcium and phosphate were measured after in vitro digestion in DHM before and after preparation of DHM with the following additives according to hospital protocols: calcium glubionate, sodium potassium phosphate, calcium glubionate and sodium potassium phosphate added together, Similac human milk fortifier, Similac NeoSure, or Enfamil Enfacare. Results: The percentage of dialyzable calcium in DHM with added calcium and calcium and phosphate together was greater than the percentage of dialyzable calcium in DHM with added powdered infant formulas (P < 0.0001). Dialyzable calcium was greater in DHM with added calcium and with added calcium and phosphate than in all other treatment groups (P < 0.0001). Dialyzable calcium in DHM without additives was not different from dialyzable calcium in DHM with added phosphate or with added powdered infant formulas. Dialyzable phosphate did not differ between the treatment groups. Conclusions: The addition of calcium alone or calcium and phosphate together increased calcium dialyzability in DHM significantly, whereas the addition of powdered human milk fortifier or formulas did not. The addition of calcium or calcium with phosphate together to DHM may provide the most dialyzable calcium.