Nonalcoholic red wine extract and quercetin inhibit LDL oxidation without affecting plasma antioxidant vitamin and carotenoid concentrations

Northern Ireland Center for Diet and Health (NICHE), University of Ulster, Coleraine BT52 1SA, Northern Ireland.
Clinical Chemistry (Impact Factor: 7.77). 08/2000; 46(8 Pt 1):1162-70.
Source: PubMed

ABSTRACT Antioxidant enrichment of LDL can increase its resistance to oxidation and hence reduce its atherogenicity. The objective of the present study was to investigate whether in vivo supplementation with nonalcoholic red wine extract and quercetin can increase the oxidative resistance of LDL, and also whether the supplementation has any effect on other antioxidative micronutrients present in the blood.
Twenty-one male subjects were supplemented with a placebo drink for 2 weeks and randomized into two groups. One group (n = 11) received the red wine extract (1 g/day, equivalent to 375 mL of red wine) and the other group (n = 10) quercetin (30 mg/day) for 2 weeks, followed by a 5-week washout period.
In the red wine extract-supplemented group, ex vivo copper-initiated oxidation of LDL (lag phase, mean +/- SD) was 40 +/- 11 min at the baseline, and increased significantly to 47 +/- 6 min [P <0.05 compared with placebo (38 +/- 4 min) and the washout values (40 +/- 5 min)]. In the quercetin-supplemented group, the lag phase was 44 +/- 11 and 40 +/- 5 min for the baseline and placebo, respectively, and increased significantly to 51 +/- 7 min [P <0.05 compared with placebo and washout (41 +/- 9 min)] after supplementation. Plasma lipids (triglycerides, total cholesterol, LDL- and HDL-cholesterol) did not change during the study period. Supplementation with red wine extract or quercetin had no effect on plasma vitamin C and E, retinol, and carotenoid concentrations.
Alcohol-free red wine extract and one of its components, quercetin, can inhibit LDL oxidation after in vivo supplementation; such "inhibition" is unrelated to changes in antioxidant vitamin and carotenoid concentrations.

Download full-text


Available from: David Thurnham, Jul 04, 2015
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We estimated the intake of individual flavonoids in a cross sectional study and clarified the major sources contributing to the flavonoid levels in the middle-aged Japanese women by a 24-h weighed dietary record study. The subjects included in the study were 516 free-living women. Each subject completed a 24-h weighed dietary record and received a health check-up. We used the Functional Food Factor database for estimating the intake of 5 major flavonoid intakes, i.e. flavan-3-ols, isoflavones, flavonols, flavanones and flavones. The mean intake of flavan-3-ols, isoflavones, flavonols, flavanones and flavones was 1277, 216, 58, 31 and 15 micromol/d, respectively. The richest source of flavan-3-ols was green tea. The 3 major food sources of isoflavone were the processed soy foods and those of flavonol were the onion, moroheiya (nalta jute) and Japanese radish leaves. Grapefruit and citrus fruit juices were the major sources of flavanones, and tsurumurasaki (malabar spinach), green pepper and grapefruit were the main sources of flavone. Furthermore, analysis of sub-samples from middle-aged Japanese women indicated that there may be an association between flavonoid intake and the levels of oxidized LDL, which might be related to the incidence of cardiovascular diseases.
    Journal of Clinical Biochemistry and Nutrition 06/2009; 44(3):231-8. DOI:10.3164/jcbn.08-231 · 2.29 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Wine polyphenols are considered to have beneficial effects on CHD and atherosclerosis. The consumption of red wine is high in Italy and France, approximately four times greater than that in the UK. This disparity in red wine consumption is thought to be the reason for the 'French paradox', where France was shown to have a coronary mortality rate close to that of China or Japan despite saturated fat intakes and cholesterol levels similar to the UK and USA. In the present review, we discuss the effects of wine and some of its polyphenol constituents on early pathological indicators of CHD such as plasma lipids, the endothelium and vasculature, platelets and serum antioxidant activity. The review also examines whether the polyphenols or the alcohol in wine is responsible for the effects on markers of heart disease. The present review concludes that red wine polyphenols have little effect on plasma lipid concentrations but wine consumption appears to reduce the susceptibility of LDL to oxidation and increase serum antioxidant capacity. However, these effects do depend on the amount of wine and period of supplementation. Authors who have examined specific polyphenols suggest that some phenolics appear to have endothelium-dependent vaso-relaxing abilities and some a positive effect on NO concentrations. Red wine phenolics also have an inhibitory effect on platelet aggregation, and individual phenolics also have a similar effect in vitro, although it should be noted that there are often discrepancies as large as ten-fold between the concentrations of polyphenolics tested in vitro and their measured levels in vivo. Evidence suggests that alcohol has a positive synergistic effect with wine polyphenols on some atherosclerotic risk factors. Thus evidence that wine drinking is beneficial for cardiac health continues to accumulate but more research is required to understand fully and exactly the functions of red wine polyphenols.
    Nutrition Research Reviews 07/2004; 17(1):111-30. DOI:10.1079/NRR200482 · 3.86 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To study serum quercetin concentrations of subjects consuming berries or habitual Finnish diets. Randomized parallel dietary intervention. Forty healthy men (age 60 y). Twenty subjects consumed 100 g/day of berries (black currants, lingonberries and bilberries) for 8 weeks. Twenty subjects consuming their habitual diets served as controls. Fasting blood samples were obtained 2 weeks prior to the study, at baseline, and at 2, 4 and 8 weeks. Intake of quercetin was assessed from 3 day food records collected at baseline and at 8 weeks. The serum quercetin concentrations were significantly higher in the subjects consuming berries compared to the control group (P=0.039 ANCOVA with repeated measures). During the berry consumption period the mean serum concentrations of quercetin ranged between 21.4 and 25.3 micro g/l in the berry group, which was 32-51% higher compared with the control group. According to 3 day food records, there was no difference in quercetin intake at baseline, but at 8 weeks the intake was 12.3+/-1.4 mg/day (mean+/-s.e.m.) in the berry group and 5.8+/-0.6 mg/day in the control group (P=0.001). The results indicate that the berries used in this study are a good source of bioavailable quercetin.
    European Journal of Clinical Nutrition 02/2003; 57(1):37-42. DOI:10.1038/sj.ejcn.1601513 · 2.95 Impact Factor