Dietary phosphorus reduction by pretreatment of human breast milk with sevelamer

Hyperphosphatemia leading to hyperparathyroidism and ultimately renal osteodystrophy is a well-known complication of chronic renal failure. A new hydrogel binder, sevelamer, has recently become available for use in hyperphosphatemic patients with renal failure. We had previously mixed the capsule with pumped breast milk and formula, but discovered that the hydrogel formed a viscous solution that infants were unable or unwilling to swallow. We therefore evaluated the phosphorus content of fresh and frozen breast milk before and after treating with different doses of sevelamer at different temperatures and for varying lengths of time. The hydrogel bound promptly to phosphorus, reducing the phosphorus content 78% within 5 min. The viscous hydrogel settled to the bottom of the container within 10 min allowing the supernatant to be easily decanted. We also evaluated the breast milk for changes in other electrolytes, osmolality, pH, and macronutrient content. These results show that fresh or frozen breast milk can be safely pretreated with sevelamer without significantly changing its macronutrient or ionic content, with the exception of calcium and protein. The supernatant can be fed to infants or instilled through a gastrostomy tube without difficulty since the viscous hydrogel settles rapidly to the bottom of the container.