Jaboticaba (Plinia cauliflora), a typical Brazilian fruit, as a strategy to modulate inflammation, oxidative stress and gut dysbiosis in patients with chronic kidney disease: study protocol for a randomised, controlled dietary crossover trial.

Jaboticaba, Plinia cauliflora [Mart.] Kausel (Myrtaceae) is a native Brazilian fruit high in bioactive compounds with potent antioxidant and anti-inflammatory properties. We present the first protocol (randomised crossover with a washout period) for a clinical trial investigating the effects of consuming jaboticaba peel extract on inflammation, oxidative stress and gut dysbiosis in patients with chronic kidney disease (CKD) undergoing haemodialysis. Thirty eligible patients will be randomly assigned to the intervention group (3·3 g/d of jaboticaba peel extract, providing 650 mg/d of phenolic compounds) or to the placebo group (corn starch). The total daily dose will be administered as four capsules, divided into two doses per day, for 2 months. Following the washout period (2 months), patients will continue the supplementation in a crossover design for the same duration. Blood and fecal samples, food intake data and anthropometric measurements will be evaluated. Inflammatory markers and antioxidant enzymes will be assessed using real-time protein chain reaction, cytokine plasma levels will be measured by Luminex, and uremic toxin plasma levels will be analysed using high-performance LC. The fecal microbiome will be evaluated through high-throughput sequencing of the 16S rRNA gene amplicons. Conducting a rigorously designed trial using jaboticaba will provide essential information and generate new evidence to support nutritional strategies that utilise typical Brazilian fruits for patients with CKD.