Phosphorus Additives in Food and their Effect in Dialysis Patients

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There is substantial epidemiologic evidence linking hyperphosphatemia and cardiovascular and all-cause mortality among dialysis patients (1,2). Therefore, control of hyperphosphatemia is a crucial element of the routine clinical care of dialysis patients. Theoretically, control of serum phosphorus levels can be achieved by the right combination of decreased dietary phosphorus intake, decreased GI phosphorus absorption by phosphate binders, and increased phosphorus elimination via dialysis. However, the clinical reality is that despite the widespread use of high-efficiency dialyzers, new phosphorus binders, and usual nutritional education, the average serum phosphorus in dialysis patients remains higher than the levels recommended by practice guidelines, except in patients on long nocturnal hemodialysis (3). The lack of attention by practicing nephrologists to dietary phosphorus restriction in general, and more specifically the lack of awareness regarding the increasing consumption of processed foods rich in phosphate additives, may significantly contribute to limit the efficacy of the current interventions (4). Estimation of the dietary intake of phosphorus should consider not only phosphorus contained in natural food, but also phosphorus added in processing food. In general, foods high in protein like meats, milk, eggs, and cereals are also naturally high in phosphorus and traditionally have represented the main source of dietary phosphorus (5). However, this is changing as phosphates are currently being added to a large and increasing number of processed foods, including meats, cheeses, dressings, beverages, and bakery products (6–8). As a result, and depending on the food choices, such additives may increase the phosphorus intake by as much as 1.0 g/d (7). Phosphorus in additives is more readily absorbed than that from foods naturally high in phosphorus; as a result, additives will have a greater effect on hyperphosphatemia than an equivalent amount of naturally …