Resistant starch type-2 enriched cookies modulate uremic toxins and inflammation in hemodialysis patients: a randomized, double-blind, crossover and placebo-controlled trial

Background: The aim of this study was to evaluate the effect of resistant starch (RS) enriched cookies supplementation on mRNA expression of nuclear transcription factors (nuclear erythroid 2-related factor, Nrf2; nuclear factor kappa-B, NF-kappa B), involved with inflammation and on uremic toxins levels produced by the gut microbiota in hemodialysis (HD) patients. Methods: A randomized, double-blind, placebo-controlled crossover study with 26 HD patients was conducted. The patients were assigned to either resistant starch enriched cookies (16 g of RS per day) or placebo cookies supplementation during the first four weeks. After the washout period, patients were supplemented again, in the form of a crossover, for another 4 weeks. Nrf2, NF-kappa B, and antioxidant enzymes mRNA expression were measured by rt-PCR and protein expression by western blotting assay from isolated peripheral blood mononuclear cells (PBMC). Oxidative stress and inflammatory biomarkers, as well as uremic toxins, were evaluated. Intention-to-treat analysis was performed, using the proc mixed procedure in SAS. Results: In RS group, post-treatment mean mRNA Nrf2 expression was market increased from baseline values, associated with a high expression of NQO1 protein. Besides, IS plasma levels were reduced in the RS group. No significant difference was observed in the placebo group. Conclusion: Our results suggested that resistant starch enriched cookies may be a good nutritional strategy to reduce indoxyl sulfate levels derived from the gut microbiota and also attenuate the inflammation in hemodialysis patients.