Balancing nutrition and serum phosphorus in maintenance dialysis

Elevated serum phosphorus levels are common in patients with chronic kidney disease and are associated with heart and vascular disease, conditions that in turn are associated with increased mortality. Accurately managing phosphorus intake by restricting dietary protein alone can prove challenging because protein from different sources can contain varying amounts of available phosphorus. Additives used in processed foods frequently are high in inorganic phosphorus, which is readily absorbed, compounding this difficulty. Recent evidence suggests that dietary protein restriction in some cases may do more harm than good in some patients treated with maintenance hemodialysis because protein restriction can lead to protein-energy wasting, which is associated with increased mortality. Accordingly, phosphorus binders are important for managing hyperphosphatemia in dialysis patients. Managing hyperphosphatemia in patients with late-stage chronic kidney disease requires an individualized approach, involving a combination of adequate dietary advice, phosphate-binder use, and adjustments to dialysis prescription. We speculate that increased use of phosphate binders could allow patients to eat more protein-rich foods and that communicating this to patients might increase their perception of their need for phosphate binders, providing an incentive to improve adherence. The aim of this review is to discuss the challenges involved in maintaining adequate nutrition while controlling phosphorus levels in patients on maintenance hemodialysis therapy.