Dietary phosphorus restriction in advanced chronic kidney disease: merits, challenges, and emerging strategies

Hyperphosphatemia is an independent risk factor for mortality in patients on maintenance dialysis. Since phosphorus clearance by standard three times-weekly dialysis is insufficient to balance ongoing dietary phosphorus intake, strategies to prevent absorption of dietary phosphorus are essential for attenuating increased serum levels. Dietary phosphorus binders are used widely for this purpose but dietary phosphorus restriction is relatively underutilized, most likely because of the logistical complexity of instituting and monitoring a low phosphorus diet, and for fear of worsening protein-energy wasting, which itself is a potent risk factor for mortality. In this review, we propose sustainable strategies for reducing phosphorus intake while avoiding exacerbation of protein-energy wasting. The approach is based on recognition of the dissociation between protein and phosphorus content in phosphorus-rich processed foods and the varying phosphorus bioavailability in different dietary sources. Controlling serum phosphate levels is among the most challenging aspects of day-to-day dialysis care but integration of sensible dietary interventions will likely improve phosphorus control.