Fiber Supplementation Lowers Plasma p-Cresol in Chronic Kidney Disease Patients

Abstract

To determine the effects of supplemental fiber on plasma p-cresol, stool frequency, and quality of life (QoL) in chronic kidney disease (CKD) patients. In a 12-week single-blind study, participants were provided with control muffins and supplements (5.5g sucrose/day) for 2weeks, muffins containing 10g/day pea hull fiber and control supplements for 4weeks, and muffins with 10g/day pea hull fiber and 15g/day inulin as a supplement for 6weeks. Individuals with CKD (n=13; 6 males, 7 females; aged 65±3years; estimated glomerular filtration rate <50mL/minute/1.73(2)) completed the study. Plasma p-cresol was determined by gas chromatography-mass spectrometry, stool frequency by 5-day journals, and QoL by the KDQOL-36™. Plasma p-cresol decreased from 7.25±1.74mg/L during week 1 to 5.82±1.72mg/L during week 12 (P<.05), and in participants with high compliance (>70% inulin intake), from 6.71±1.98mg/L to 4.22±1.16mg/L (P<.05). Total fiber intake increased from 16.6±1.7g/day during control to 26.5±2.4g/day (P<.0001) with the added pea hull and to 34.5±2.2g/day with pea hull and inulin (P<.0001). Stool frequency increased from 1.4±0.2 stools/day during control to 1.9±0.3 stools/day during both fiber periods (P<.05). No change in overall QoL was observed. Supplementing the diet of CKD patients with fiber may be a dietary therapy to reduce p-cresol and improve stool frequency.