Low Phosphate Diet Linked to Premature Death for Dialysis Patients

Kathleen Blanchard's picture

Restricting kidney dialysis patients to a low phosphate diet might increase the risk of premature death and nutritional deficiencies, suggested by new research.

More Liberal Phosphate Intake Compared to Dietary Restrictions among Kidney Dialysis Patients

Findings from investigators at Brigham and Women's Hospital and Harvard Medical School shows a more liberal diet that includes natural sources of phosphorus prolonged life in an analysis of data from 1751 patients on dialysis.

The study, led by Steven Brunelli, MD, MSCE (Brigham and Women's Hospital and Harvard Medical School), Katherine Lynch, MD (Beth Israel Deaconess Medical Center), followed the dialysis patients for an average of 2.3 years, analyzing the effect of restricting foods that contain phosphorus.

Compared to those given a restricted phosphate diet of less than 870mg per day, the patients allowed over 1000mg per day were 29 percent less likely to die.


"Our data suggest that prescription of low phosphate diets did not improve survival among hemodialysis patients and may, in fact, be associated with greater mortality," said Dr. Brunelli, who adds it may be that limiting phosphates also compromises intake of protein needed for good nutrition.

Kidney dialysis patients in the study who were non-black, not taking vitamin D and whose phosphate levels were not elevated were found to have longer survival from eating a more liberal phosphate diet. Patients on dietary restrictions were also found to be more likely to need vitamin supplements.

The study that took place from 1995 to 2001 applies to dietary foods with natural phosphates and not those with additives. The authors note at the time of the study food additives were less common and require more investigation.

Added phosphates are absorbed more readily and found in foods that are not as nutrient dense as foods with natural phosphates and are added to flour, cheeses and colas. Natural sources of phosphorus include leafy vegetables, fruits, meat, and poultry products, according to information from the Food and Nutrional Board, National Academy of Sciences.

The study suggests kidney dialysis patients on restricted phosphate diets have poorer survival and are more likely to die prematurely. The findings are Published December 9 in theClinical Journal of the American Society Nephrology (CJASN).