Effects of High Amylose-Resistant Starch on Gut Microbiota and Uremic Toxin Levels in Patients With Stage-G3a-G4 Chronic Kidney Disease: A Randomized Trial

Abstract

ObjectiveThis study was designed to determine the effect of 16 weeks of supplementation with Hi-maize 260 resistant starch on the gut microbiota, uremic toxins (indoxyl sulfate and p-cresyl sulfate), markers of inflammation and oxidative stress along with vascular function in patients with stage G3a-G4 chronic kidney disease (CKD). Design& Methods: This was a double-blind, placebo-controlled, parallel-arm, randomized controlled trial. Sixty-eight patients with stage G3a-G4 CKD were randomized to either resistant starch with usual care or placebo and usual care. Patients attended four testing sessions: two baseline visits, and follow-up visits at 8 and 16 weeks. Fasting blood samples, resting brachial and central blood pressures, along with arterial stiffness, were collected at visits (1 or 2), and weeks 8 and 16. A stool sample was collected for analysis of microbial composition at baseline and week 16. Patients were randomized after the baseline visits. ResultsPatients receiving the resistant starch had a reduction in p-cresyl sulfate at week 16. This reduction was associated with a decrease in microbial α-diversity between baseline and week 16 (Chao1 p=0.014, Shannon p=0.017, PD p= 0.046, and Simpson p=0.017) as well as increases in Subdoligranulum (p=0.03) and Oscillospiraceae UCG 002 (p=0.02) and decreases in Bacteroides (p=0.009).There were no changes in microbial beta diversity and other biomarkers or markers of vascular function following the 16-week period Conclusion: Sixteen weeks of supplementation of resistant starch in patients with stage G3a-G4 CKD led to changes in microbial composition that were associated with a significant reduction in p-cresyl sulfate.