This is a chronic study, which consists of a longitudinal, randomized, double-blind, crossover clinical study, with a washout period and placebo-controlled trial. Thirty patients with CKD undergoing hemodialysis will be selected (according to sample calculation, considering p=0.05 and test power of 80%). Randomization will be computerized in a 1:1 ratio, with a block size of 15 (Jaboticaba and Control groups), to receive jaboticaba peel extract or placebo. Eligible patients of both genders, previously evaluated and authorized by the medical and nutritionist team, will be invited to participate in the research in person and verbally, during nutritional consultations at the Prodoctor Hemodialysis Clinic. The intervention consists of supplementing 4 capsules/day, providing 3.3g of jabuticaba peel extract daily, containing 600mg of phenolic compounds, or the same amount of placebo, corn starch, for one month. After the end of this first intervention, blood and fecal samples will be collected again. Followed by a 2-month washout period. After 2 months, blood and fecal samples will be collected again from these patients. The crossover will then begin, the second moment of supplementation in which the patients who received the jaboticaba peel extract in the first moment start to receive the placebo, and the patients who received the placebo initially began to receive jabuticaba peel extract supplementation for one month. At the end of the second supplementation period, blood and fecal samples will be collected.
