The effects of prebiotic, probiotic, and synbiotic supplementation on blood parameters of renal function: A systematic review and meta-analysis of clinical trials

Objectives: Recent studies have demonstrated promising results regarding possible improvements in renal function after prebiotic, probiotic, and synbiotic supplementation. The aim of this review was to demonstrate whether such supplementation will improve renal profile indexes including glomerular filtration rate (GFR), creatinine, blood urea nitrogen (BUN), uric acid (UA), and urea. Method: The meta-analysis included all studies that examined the effect of prebiotic, probiotic, and synbiotic supplements on one or more renal function parameters and had a control group. We searched July 1967 through to March 2016 MEDLINE, Scopus, and Google Scholar databases. Results: Of 437 studies, 13 were eligible for inclusion in the meta-analysis. GFR levels tended to be reduced; whereas creatinine levels increased in the intervention group compared with the placebo group, both in a non-significant manner. The pooled effect on BUN demonstrated a significant decline compared with the placebo group (MD,-1.72 mmol/L; 95% confidence interval [CI],-2.93 to-0.51; P = 0.005). Urea significantly decreased after intervention (-0.46 mmol/L; 95% CI,-0.60 to-0.32; P<0.0001). The UA levels significantly increased in the intervention group compared with the placebo group (12.28 mu mol/L; 95% CI, 0.85-23.71; P = 0.035). Conclusion: This study showed a significant increase in UA and a decrease in urea and BUN. The use of prebiotic, probiotic, and synbiotic supplements among those with compromised renal function or those at risk for renal failure should be limited until large-scale, well-designed randomized controlled trials prove the safety and efficacy of these supplements in improving renal function. (C) 2018 Elsevier Inc. All rights reserved.