The Effect of Dietary Supplementation With Curcumin on Redox Status and Nrf2 Activation in Patients With Nondiabetic or Diabetic Proteinuric Chronic Kidney Disease: A Pilot Study.

OBJECTIVE: Chronic kidney disease (CKD) is a worldwide public health problem, and proteinuria may accelerate the progression of CKD, being oxidative stress a common mechanism in nondiabetic or diabetic proteinuric kidney disease. This study was designed to evaluate the effect of the dietary supplementation with curcumin (CUR) on the redox status and the nuclear factor erythroid 2-related factor 2 (Nrf2) activation in patients with nondiabetic or diabetic proteinuric CKD.

DESIGN: Randomized double-blind placebo-controlled clinical trial.

SUBJECTS: A total of 101 Mexican patients from the National Institute of Cardiology "Ignacio Chavez", with nondiabetic or diabetic proteinuric CKD (proteinuria ≥ 1 g protein/24 hours), aged 20 to 70 years; 60% were male, and 51% were diabetic.

INTERVENTION: Patients with nondiabetic proteinuric CKD received placebo (n = 26) or CUR 320 mg/day (n = 24) for 8 weeks, and patients with diabetic proteinuric CKD were intervened with placebo (n = 23) or CUR 320 mg/day (n = 28) for the same period.

MAIN OUTCOME MEASURE: Anthropometrical, clinical, and biochemical characteristics, as well as oxidative stress markers, antioxidant enzyme activities and Nrf2 activation were evaluated at baseline and after intervention.

RESULTS: The intervention with CUR did not improve proteinuria, estimated glomerular filtration rate, or lipid profile. However, in plasma, CUR attenuated lipid peroxidation in individuals with nondiabetic proteinuric CKD (P<.05) and enhanced the antioxidant capacity in subjects with diabetic proteinuric CKD (P<.05). No effect of CUR was observed on the antioxidant enzymes activities or Nrf2 activation.

CONCLUSIONS: Dietary supplementation with CUR has the potential to reduce oxidative stress in Mexican patients with nondiabetic or diabetic proteinuric CKD. Studies with higher doses of CUR and longer follow-up are granted to confirm our findings.