Title

Independent and additive effects of raisins or walking on biomarkers of coronary heart disease in men and women aged 50-70 years

Date of Completion

January 2008

Keywords

Health Sciences, Nutrition

Degree

Ph.D.

Abstract

Raisins are a significant source of dietary fiber and polyphenols, which may reduce cardiovascular disease (CVD) risk by affecting lipoprotein metabolism, inflammation, oxidative stress and satiety hormones. Walking is a low intensity exercise intervention that may also reduce CVD risk. The purpose of this study was to evaluate the effects of consuming raisins, low intensity exercise, or their combination on blood pressure, plasma lipids, apolipoproteins, glucose, insulin, inflammatory cytokines, cholesteryl ester transfer protein (CETP) activity, oxidized LDL, urinary isoprostanes and LDL receptor mRNA abundance. Thirty-four men and postmenopausal women were matched for weight and gender and randomly assigned to consume 1 cup raisins/d (RAISIN), increase the amount of steps walked/d (WALK) or a combination of both interventions (RAISIN + WALK). The subjects completed a 2 wk run-in period, followed by a 6 wk intervention. Systolic blood pressure was reduced for all subjects (P < 0.001). Plasma total cholesterol decreased by 9.4% in all subjects (P < 0.005), which was explained by a 13.7% reduction in plasma LDL cholesterol (LDL-C) (P < 0.001). Plasma triglycerides (TG) concentrations decreased by 19.5% for WALK (P < 0.05 for group effect). Plasma TNF-α decreased from 3.5 ng/L to 2.1 ng/L for RAISIN (P < 0.025 for time and group X time effect). All subjects had a reduction in plasma sICAM-1 (P < 0.01). There was a significant group effect for plasma leptin (P < 0.05); concentrations increased for RAISIN and RAISIN + WALK. LDL receptor mRNA abundance was increased for all subjects (P < 0.05). Apolipoprotein CIII decreased by 12.3% for WALK from pre- to post-intervention (P < 0.05), but was unchanged for RAISIN and RAISIN + WALK. A significant time effect was present for plasma ghrelin; concentrations were elevated post-intervention for RAISIN and RAISIN + WALK (P < 0.05). This research shows that simple lifestyle modifications, adding raisins to the diet or increasing steps walked, have distinct beneficial effects on CVD risk. Either intervention alone or in combination improved blood pressure, lipoprotein metabolism and markers of inflammation. Raisin consumption altered satiety hormones to potentially improve weight control. ^