Dietary Phosphorus and Metabolic Health in CKD and ESKD

The contribution of dietary phosphorus in the pathogenesis of chronic kidney disease associated mineral bone disease (CKD-MBD) and the management of phosphorus intake in CKD patients are essential to slow down disease progression and improve patient outcomes. In patients with CKD, and most likely in the general population, phosphorus retention and overload can affect four critical aspects of the cardiovascular system: increased arterial blood pressure, vascular and valvular calcification and left ventricular hypertrophy. All of these factors contribute to increased cardiovascular risk and mortality. Intestinal absorption of phosphorus from a mixed diet is approximately 60-70% of the dietary phosphorus content, with lower rates for organic phosphorus from plant sources and higher rates for inorganic phosphorus from processed foods containing additives. The widespread use of phosphate additives in processed foods and the high consumption of animal protein in the Western diet have led to a steady increase in phosphate consumption in recent decades. Although it is unclear whether this high phosphorus intake has adverse effects in people with normal kidney function, several studies have found that increased dietary phosphorus contributes to the progression of CKD and cardiovascular damage. High phosphorus intake may be detrimental, but there is no clear evidence that it should be avoided in the general population. On the contrary, kidney function impairment is the setting in which modulation of phosphorus intake is justified and easy to implement by restricting/reducing protein intake. However, it is quite difficult to implement phosphorus restriction in dialysis patients because of the conflicting recommendation of high protein intake. Educational approaches, together with solid motivation and adherence by patients and caregivers, are needed to achieve the goal of successful dietary phosphate management in CKD patients.