Effect of daily consumption of cranberry beverage on insulin sensitivity and modification of cardiovascular risk factors in adults with obesity: a pilot, randomised, placebo-controlled study

摘要

Cranberries are high in polyphenols, and epidemiological studies have shown that a high-polyphenol diet may reduce risk factors for diabetes and CVD. The present study aimed to determine if short-term cranberry beverage consumption would improve insulin sensitivity and other cardiovascular risk factors. Thirty-five individuals with obesity and with elevated fasting glucose or impaired glucose tolerance participated in a randomised, double-blind, placebo-controlled, parallel-designed pilot trial. Participants consumed 450 ml of low-energy cranberry beverage or placebo daily for 8 weeks. Changes in insulin sensitivity and cardiovascular risk factors including vascular reactivity, blood pressure, RMR, glucose tolerance, lipid profiles and oxidative stress biomarkers were evaluated. Change in insulin sensitivity via hyperinsulinaemic-euglycaemic clamp was not different between the two groups. Levels of 8-isoprostane (biomarker of lipid peroxidation) decreased in the cranberry group but increased in the placebo group (-2 center dot 18v. +20 center dot 81 pg/ml;P= 0 center dot 02). When stratified by baseline C-reactive protein (CRP) levels, participants with high CRP levels (>4 mg/l) benefited more from cranberry consumption. In this group, significant differences in the mean change from baseline between the cranberry (n10) and the placebo groups (n7) in levels of TAG (-13 center dot 75v. +10 center dot 32 %;P= 0 center dot 04), nitrate (+3 center dot 26v. -6 center dot 28 mu mol/l;P= 0 center dot 02) and 8-isoprostane (+0 center dot 32v. +30 center dot 8 pg/ml;P= 0 center dot 05) were observed. These findings indicate that 8 weeks of daily cranberry beverage consumption may not impact insulin sensitivity but may be helpful in lowering TAG and changing certain oxidative stress biomarkers in individuals with obesity and a proinflammatory state.