Fiber medicine

Dietary fiber intake associated with reduced uremic toxins

According to a new study, dietary fiber may help reduce uremic toxins in patients with chronic kidney disease (CKD).

In a meta-analysis of 10 randomized controlled trials (7 high quality) involving 292 patients, dietary fiber supplements significantly reduced serum levels of indoxyl sulfate, p-cresyl sulfate, urea nitrogen blood and uric acid levels by a standardized mean difference of 0.55, 0.47, 0.31, and 0.60, respectively, compared to placebo or another control, Xiao-Hua Wang, PhD, of First Hospital affiliate of Soochow University in Suzhou, China, and colleagues reported in the Kidney Nutrition Journal. The reduction in indoxyl sulphate was 0.73 higher in supplemented dialysis patients. Dietary fiber supplements did not significantly reduce serum creatinine in the primary analysis, but subgroup analyzes indicated a significant 1.04-fold reduction in creatinine in supplemented patients without diabetes per report to witnesses. According to the researchers, people with diabetes consume more protein and may have higher creatinine production.

The researchers found no significant difference between fiber supplement dose (less than or greater than 20 g/d) or duration of intervention (less or greater than 8 weeks), but further testing is needed. Fiber supplements studied included bran, lignin, cellulose, arabinoxylan, inulin, beta-glucan, guar gum, gum arabic, pectin, psyllium, fructo-oligosaccharides and resistant starch. Future studies should also look at total dietary fiber, Dr. Wang’s group noted.

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According to Dr. Wang’s team, only 30% of indoxyl sulfate and p-cresyl sulfate, protein-bound uremic toxins produced by gut bacteria, are removed by hemodialysis, highlighting the need for additional strategies to reduce uremic toxins. These findings can help inform recommendations for clinical practice.


Yang HL, Feng P, Xu Y, Hou YY, Ojo O, Wang XH. The role of dietary fiber supplementation in the regulation of uremic toxins in patients with chronic renal failure: a meta-analysis of randomized controlled trials. Published online March 16, 2021. J Ren Nutr. doi:10.1053/j.jrn.2020.11.008