CKD Patients Benefit From Vegetarian Diet

INDIANAPOLISEating a diet rich in vegetables rather than meat may help patient with chronic kidney disease (CKD) avoid accumulating toxic levels of phosphorous in their bodies, according to a new study published in the Clinical Journal of the American Society of Nephrology.

Researchers from Indiana University School of Medicine and Roudebush Veterans Affairs Medical Center suggest the source of phosphorous in the diet has an important effect on keeping phosphate-to-protein ratio balanced among patients with CKD.

Individuals with kidney disease cannot adequately rid the body of phosphorus, which is found in dietary proteins and is a common food additive. Kidney disease patients must limit their phosphorous intake, as high levels of the mineral can lead to heart disease and death. While medical guidelines recommend low phosphorus diets for patients with chronic kidney disease (CKD), phosphorus content is not listed on food labels.

The researchers studied the effects of vegetarian and meat-based diets on phosphorous levels in nine patients with CKD. Patients followed a vegetarian or meat-based diet for one week, followed by the opposite diet two to four weeks later. Blood and urine tests were performed at the end of each week on both diets. Despite equivalent protein and phosphorus concentrations in the two diets, patients had lower blood phosphorus levels and decreased phosphorus excretion in the urine when they were on the vegetarian diet compared with the meat-based diet. While the investigators did not determine the reason for this difference, a grain-based diet has a lower phosphate-to-protein ratio and much of the phosphate is in the form of phytate, which is not absorbed in humans.

This study demonstrates that the source of protein has a significant effect on phosphorus homeostasis in patients with CKD. Therefore, dietary counseling of patients with CKD must include information on not only the amount of phosphate but also the source of protein from which the phosphate derives.