ABSTRACT
A direct and independent association between serum phosphate (P) levels and mortality has been reported. Higher circulating P concentrations, although still within the normal range, have been associated with unfavorable outcomes in normal subjects, as well as in predialysis renal cohorts. Experimental data support the notion that P overload may decrease survival expectancy, directly inducing vascular, skeletal, and renal aging. Phosphorus balance results from the interplay of dietary intake, intestinal absorption, glomerular filtration, and tubular reabsorption of phosphorus (TRP), as well as hormonal factors. The accurate estimation of P balance, however, is hampered by several methodological weaknesses and becomes critical when renal function declines. The present chapter critically discusses the physiology of P metabolism in humans, then deals with uncertainties regarding dietary P intake and P balance assessment, and finally addresses more recent data on P intake and mortality extending from the general population to dialysis cohorts.
