Effects of pomegranate extract supplementation on cardiovascular disease risk and physical function in patients with chronic renal failure

BACKGROUND: Patients with chronic kidney disease (CKD) undergoing maintenance hemodialysis therapy suffer from a variety of co-morbid conditions that greatly decrease physical function and increase cardiovascular disease (CVD) mortality. Oxidative stress has been implicated in increasing CVD risk and declining muscle function in hemodialysis patients, but little is known about the efficacy of antioxidant treatment in this population. A recent one year intervention in dialysis patients found that consumption of pomegranate juice, a rich source of polyphenol antioxidants, significantly lowered serum markers of inflammation and oxidative stress, reduced carotid atherosclerosis, and lowered the prevalence of hospitalizations due to infection. Despite these potential benefits, pomegranate juice is normally contraindicated in hemodialysis patients because its high potassium content may contribute to hyperkalemia-induced cardiac dysfunction. As a result, the efficacy of alternative antioxidant therapies needs to be investigated. PURPOSE: The purpose of this study was to evaluate the effect of 6-month oral supplementation with a pomegranate extract containing a high concentration of antioxidant polyphenols, but low potassium content, on cardiovascular risk, physical function, oxidative stress and inflammation in hemodialysis patients. METHODS: Thirty-three hemodialysis patients were recruited (20 men, 13 women; 54.3±2.1 years). Subjects were randomized to pomegranate (POM, n=16) or placebo (CON, n=17) group. At baseline and 6 months following the start of the intervention, cardiovascular risk was assessed by measuring arterial structure and function using a combination of vascular ultrasound and arterial tonometry, as well as circulating markers of oxidative stress and inflammation. In addition, a variety of tests were used to assess muscle strength and physical function. RESULTS: Systolic and diastolic blood pressure (BP) were reduced by 24.2±13.7 mmHg and 10.9±5.3 mmHg, respectively, in POM (p<0.05), but did not change in CON. However, the BP differences in the POM group were no longer significant after controlling for baseline BP levels. Paraoxonase-1 activity, a measure of antioxidant capacity, increased by 26.6% (p