Skip to main content

Main menu

  • Home
  • About
    • Clinical Chemistry
    • Editorial Board
    • Most Read
    • Most Cited
    • Alerts
    • CE Credits
  • Articles
    • Current Issue
    • Early Release
    • Future Table of Contents
    • Archive
    • Browse by Subject
  • Info for
    • Authors
    • Reviewers
    • Subscribers
    • Advertisers
    • Permissions & Reprints
  • Resources
    • AACC Learning Lab
    • Clinical Chemistry Trainee Council
    • Clinical Case Studies
    • Clinical Chemistry Guide to Scientific Writing
    • Clinical Chemistry Guide to Manuscript Review
    • Journal Club
    • Podcasts
    • Q&A
    • Translated Content
  • Abstracts
  • Submit
  • Contact
  • Other Publications
    • The Journal of Applied Laboratory Medicine

User menu

  • Subscribe
  • My alerts
  • Log in

Search

  • Advanced search
Clinical Chemistry
  • Other Publications
    • The Journal of Applied Laboratory Medicine
  • Subscribe
  • My alerts
  • Log in
Clinical Chemistry

Advanced Search

  • Home
  • About
    • Clinical Chemistry
    • Editorial Board
    • Most Read
    • Most Cited
    • Alerts
    • CE Credits
  • Articles
    • Current Issue
    • Early Release
    • Future Table of Contents
    • Archive
    • Browse by Subject
  • Info for
    • Authors
    • Reviewers
    • Subscribers
    • Advertisers
    • Permissions & Reprints
  • Resources
    • AACC Learning Lab
    • Clinical Chemistry Trainee Council
    • Clinical Case Studies
    • Clinical Chemistry Guide to Scientific Writing
    • Clinical Chemistry Guide to Manuscript Review
    • Journal Club
    • Podcasts
    • Q&A
    • Translated Content
  • Abstracts
  • Submit
  • Contact
Research ArticleNutrition

Nonalcoholic Red Wine Extract and Quercetin Inhibit LDL Oxidation without Affecting Plasma Antioxidant Vitamin and Carotenoid Concentrations

Mridula Chopra, Patricia E.E. Fitzsimons, John J. Strain, David I. Thurnham, Alan N. Howard
Published August 2000
Mridula Chopra
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Patricia E.E. Fitzsimons
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
John J. Strain
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
David I. Thurnham
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Alan N. Howard
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Figures & Data
  • Info & Metrics
  • PDF
Loading

Abstract

Background: 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.

Methods: 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.

Results: 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.

Conclusions: 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.

The oxidation of LDL is believed to play an important role in the pathogenesis of atherosclerosis (1) and hence the risk of cardiovascular disease. Cardio-protective effects of red wine have been suggested by several researchers, and these are attributed both to HDL-cholesterol-enhancing effects of the alcohol component (2)(3) and to antioxidant functions of its flavonoid constituents (4)(5). However, human studies that investigated the antioxidant protection of LDL after red wine consumption have produced conflicting reports, with two groups reporting positive effects (6)(7) and a third group showing no effect (8). The discrepancies in the results may be related to the methodologies used in the various studies (9) and/or variations in the flavonoid content of the wines (10)(11). The main phenolic components of red wine are anthocyanins, catechins, resveratrol, phenolic acids, and the flavonols quercetin and myricetin (9)(12). The concentrations of these components in the red wine can vary widely (13)(14)(15). Although most of the phenolic components of red wine have shown antioxidant properties in vitro (16)(17)(18), the antioxidant potential of individual components in vivo is not known.

In the present study, we investigated the effect of nonalcoholic red wine extract and one of its constituents, quercetin, on the oxidative resistance of LDL. Interaction of dietary antioxidants in blood or during absorption from the gut can potentially increase or reduce the effect of an antioxidant supplement. We therefore also measured the effect of supplementation on plasma vitamins A, C, and E, and carotenoid concentrations.

Materials and Methods

Subjects

Twenty-two nonsmoking male volunteers (average age, 46 years; range, 33–65 years) were recruited from the University of Ulster staff. Eight subjects were regular alcohol drinkers (≥10 units/week), six were occasional drinkers (≤5 units/week), and eight were nondrinkers. All participants were asked to complete a lifestyle questionnaire. A screening blood sample showed that all subjects had values within the reference intervals for full blood count (white blood cells, platelets, and red blood cells), hemoglobin, hematocrit, and liver enzymes (alkaline phosphatase, aspartate aminotransferase, alanine transferase, and γ-glutamyltransferase) except for one whose alanine transferase concentration was slightly outside the reference interval (70 U/L). A total of 21 subjects completed the study. One subject withdrew (during the placebo period) for personal reasons.

Ethical approval was obtained from the University of Ulster, Ethical Committee, and the subjects gave written informed consent. Fifteen subjects were not on any medication or supplements. Those on medication or supplements were allowed to continue taking them at the same doses.

Design of the study

All subjects were supplemented with a placebo drink (blackcurrant-flavored, containing sugar, citric acid, sodium citrate, aspartame, and synthetic flavor; Cambridge Manufacturing) for the first 2 weeks. The placebo drink was given as a powder in sachets, and subjects were asked to reconstitute it with water according to their individual tastes. After the placebo period, subjects were randomized into two groups. One group received the placebo drink plus one capsule containing 1 g of red wine extract (NutrivineTM; The Howard Foundation, Cambridge, UK) daily, and the second group received the placebo drink containing 30 mg of quercetin (quercetin aglycone; Sigma) daily for 2 weeks. The supplementation period was considered sufficient because previous studies have shown an antioxidant effect after supplementation with red wine for 2 weeks (6)(9). A placebo group running in parallel with two treatment groups was considered unnecessary because both within-subject and seasonal variations in the LDL lag phase have been reported to be small in unsupplemented subjects (19)(20). Furthermore, in a pilot study, we found that the LDL lag phase was not changed when measured weekly over 4 weeks in subjects not receiving any treatment (21).

Subjects were instructed to take the supplements with food. Except for their alcohol intake, they were asked to maintain a typical but consistent dietary pattern during the course of the study. Preliminary data from the pilot study showed that the irregular consumption of alcohol, especially red wine, can affect the LDL lag phase. Subjects were therefore advised to refrain from drinking red and white wine during the study period and to limit their alcohol intake to not more than 1 unit/day. They were given food diaries to specifically record the consumption of the following foods: fruits (berries, apples, cherries, and blackcurrants), vegetables (onions, leeks, broccoli, lettuce, cabbage, tomatoes, and beans), chocolates, beverages (fruit juices, milk, tea, coffee, and cocoa) and alcohol intake. They were asked to quantify fruits and vegetables by number or portion and average size (e.g., two small apples or one large serving of beans, onions in a portion of beef stew, and so forth); beverages by glass, carton, cup, or mug (e.g., one medium glass of pure orange juice or one one-half pint carton of milk); and alcohol by bar (i.e., serving) measures (e.g., one-half pint of lager or one gin). The dietary records enabled a qualitative assessment of the amount of flavonoid-rich foods consumed during the study.

All supplements were supplied by The Howard Foundation, Cambridge and packed by Cambridge Manufacturing. The preparation of red wine extract was the same as described previously (9). The flavonoid composition of the wine extract was determined by ETS Laboratories; it contained, per gram of powder, flavonols (5 mg, including 3.5 mg of quercetin), proanthocyanidins (202 mg), phenolic acids (2 mg), monomeric catechins (18 mg), resveratrol (3.3 mg), and anthocyanins (65 mg). This dose per day was equivalent to ∼375 mL of red wine. The quercetin-supplemented group received 30 mg of quercetin/day. The supplement amount was chosen for two reasons. Epidemiological data have shown that an intake of >20 mg of quercetin/day is protective against the risk of cardiovascular disease (22)(23). Dietary quercetin is a mixture of glycosides and aglycone forms. The glycoside form from onions is known to be absorbed to a greater extent (50% more) than the aglycone (24). Because we were using the aglycone form (only one available commercially), we hypothesized that a dose >20 mg should be used. The red wine extract used in the present study contained 1.7 mg of glycoside and 1.8 mg of aglycone form of the quercetin. A 30-mg dose of aglycone quercetin therefore provided a sixfold higher dose than the wine extract (see Discussion).

Blood sampling

Fasting blood samples (10-h overnight fast) were obtained from the subjects in recumbent position using Vacutainer Tubes containing either lithium heparinate or EDTA (1.5 g/L), or no anticoagulant. The blood was collected at four time points: baseline (week 0); after the placebo supplement (week 2); after treatment with either quercetin or red wine extract (week 4); and after a 5-week washout period (week 9). A washout period of 5 weeks was used to ensure that all effects of the treatment were removed and that the baseline values were re-established.

The EDTA blood was used for the full blood count measurements. Blood from plain tubes was used to prepare serum for the liver function tests and for the measurement of a plasma lipid profile (triglycerides, total cholesterol, and LDL- and HDL-cholesterol) done at the Causeway Health and Social Services Trust Laboratory, Coleraine, Northern Ireland. Lithium heparinate blood was used for the isolation of LDL and for analysis of plasma vitamins A, C, and E and carotenoids. The plasma was prepared after centrifugation at 1000g for 10 min at 10 °C, aspirated into a universal centrifuge tube, and centrifuged for an additional 45 min at 1000g to remove the remaining cell debris. Plasma was separated within 1 h after collection of the blood.

After centrifugation, one part of plasma (0.5 mL) was immediately stabilized with 2 parts of meta-phosphoric acid (Prolabo), mixed, and snap frozen in liquid nitrogen before storage at −80 °C. Plasma aliquots of 0.5 mL were frozen at −80 °C for the analysis of fat-soluble vitamins and carotenoids at a later stage. Plasma vitamin E and carotenoid analysis was completed within 6 months, and plasma vitamin C within 10 months of the completion of the study.

Preparation of ldl

The LDL was isolated from the fresh lithium heparinate blood by density ultracentrifugation using a modified method of Chung et al. (25). Briefly, the density of plasma was adjusted by adding 0.32 g KBr/mL of plasma. The density-adjusted plasma (3.5 mL) was layered below EDTA containing a 1 g/L KBr solution (density = 1.006; pH 7.4) in Optiseal polyallomer tubes (Beckman) and centrifuged for 2.5 h under reduced pressure in a Beckman XL-70 centrifuge at 30 000g rpm at 7 °C using a NVT65 rotor. The LDL fraction was removed by puncturing the tube wall with a hypodermic needle attached to a syringe. A fraction of LDL (0.5 mL) was dialyzed immediately, and the remaining LDL was stored under nitrogen at 4 °C. Gel electrophoresis of LDL using Paragon lipoprotein gels (Beckman) showed that the LDL was free from contamination with plasma proteins and HDL.

dialysis and oxidation of LDL

LDL samples (0.5 mL) were transferred to Visking dialysis tubes [size 1; diameter, 6.3 mm (8/32 inches); Medicell International Limited] and dialyzed in deoxygenated phosphate-buffered saline (0.01 mol/L Na2HPO4, 0.16 mol/L NaCl, and 0.3 mmol/L chloramphenicol, pH 7.4) both in the absence and presence of 10 μmol/L EDTA (sodium salt). Duplicate samples were dialyzed in buffers containing either 10 μmol/L or 2 μmol/L EDTA at 4 °C for the first hour. After 1 h, those samples from the buffer containing 2 μmol/L EDTA were transferred to a buffer containing no EDTA. Samples in both flasks were dialyzed an additional 15 h at 4 °C under nitrogen.

After dialysis, the cholesterol content of the dialyzed LDL was determined using a CHOD-PAP kit from Boehringer. The kinetics of the LDL oxidation were followed by continuously monitoring the formation of conjugated dienes at 234 nm after the addition of copper as described by Puhl et al. (26). The concentrations of LDL and copper in the final reaction mixture of EDTA-free PBS buffer were 0.25 g/L total LDL (equivalent to 0.1 μmol/L LDL) and 11.7 μmol/L copper. A control, LDL prepared from pooled plasma stored in sucrose (final concentration, 6 g/L) at −80 °C, was used with every oxidation. The interassay imprecision of the lag phase (the resistance of LDL to oxidation) measurements was calculated from the lag phase measurements of control LDL and gave a CV of 4%. The intraassay CV for eight measurements on pooled dialyzed LDL was <3%.

Apolipoprotein b analysis

The apolipoprotein B (apoB) content of LDL was measured on fresh samples using Sigma diagnostic kits. The analysis was done on a COBAS Fara centrifugal analyzer by measuring the absorbance at 340 nm. The concentration of apoB was determined from a calibration curve obtained using multilevel calibrators. Two control serum samples provided with the kit were used with each run. For the first 4 weeks of the study, the mean apoB concentration was 566 ± 3.3 mg/L (CV = 0.58%) for control 1 and 1060 ± 13.0 mg/L (CV = 1.2%) for control 2. A new apoB kit was used after the washout period; with this kit, the values obtained for controls 1 and 2 were 656 and 987 mg/L, respectively. The overall CV of the assay using different kits was ∼5%.

Vitamin C (ascorbic acid) analysis

The ascorbic acid concentrations in meta-phosphoric acid extracts of plasma were determined on stored samples by the method described by Heiliger (27). Briefly, samples were thawed on a roller-mix, mixed well by inversion, and centrifuged on a microcentrifuge at 7000g for 5 min. Clear extract (20 μL) was separated on a 100 × 4.6 mm cartridge column (Phase-Sep) containing 3-μm ODS-2 Spherisorb particles. The sample was pumped at 1.0 mL/min through the column, with a pH 5.5 mobile phase containing 0.1 mol/L sodium acetate, 1 mmol/L octylamine (Fluka Chemicals), 200 mg/L disodium EDTA, and 100 mg of DL-homocysteine. An output to a chromatographic data handling system (Maxima 820, Waters; Millipore) allowed manual peak integration. The concentration of ascorbic acid was quantified based on a response factor calculated by direct injection of 40 μmol/L ascorbic acid calibrator in 100 g/L meta-phosphoric acid. Pooled plasma extract and 40 μmol/L ascorbic acid extract stored at −80 °C were run with every batch as control samples. The interassay CV was 5%, and the intraassay CV was 3%.

Vitamin E and carotenoid analysis

The plasma and LDL concentrations of vitamin E (α- and γ-tocopherol), retinol, and carotenoids were determined as described previously (28). Briefly, 0.1 mL of aqueous sodium dodecyl sulfate and 0.2 mL of an ethanolic solution of internal standard (40 mg/L tocopherol acetate) were added to 0.1 mL of sample; 1 mL of heptane containing 0.5 g/L butylated hydroxytoluene was added to the resulting mixture, and the solution was mixed vigorously for 3 min on a vortex-type mixer. The samples were centrifuged at 800g for 10 min at 10 °C. The heptane layer (0.7 mL) was removed, evaporated to dryness under a stream of nitrogen at 37 °C, and reconstituted in 0.1 mL of reconstitution mobile phase (mobile phase plus 90 mg/L butylated hydroxytoluene). A 50-μL sample was separated on a 3-μm Spherisorb ODS-2 column (10 cm × 4 mm) with mobile phase (acetonitrile-methanol-dichloromethane, 500:500:128 by volume, plus 0.01 g/L butylated hydroxytoluene) pumped at 1 mL/min. The tocopherols, retinol, and carotenoids were detected simultaneously at 292, 325, and 450 nm, respectively. The data were collected and integrated using Maxima software (Waters). The carotenoid, retinol, and tocopherol concentrations were calculated using authentic standards as described previously (28). Pooled control plasma was run with every batch of samples to calculate interassay imprecision. The interassay imprecision (CV) was <5% for the tocopherols and retinol and <10% for carotenoids.

Statistical analysis

Statistical analysis was performed by using Statistical Package for Social Sciences, Ver. 6 (SPSS Inc). The data were skewed both before and after transformation to logarithms. Therefore, the nonparametric Wilcoxon paired-rank test was used for statistical analysis. P <0.05 was considered significant.

Results

Effect of supplementation on the lag phase

A qualitative examination of food diaries completed during the placebo and supplementation periods indicated that dietary habits with respect to flavonoid-rich foods did not change during the study period. However, the LDL lag phase was significantly increased in both the red wine extract- and quercetin-supplemented groups compared with the placebo (P <0.01, Wilcoxon paired-rank test; Table 1⇓ ) and washout (P <0.02) time points.

View this table:
  • View inline
  • View popup
Table 1.

Changes in plasma lipids and apoB from subjects during the study period.

Because there was no difference in the lag phase measured on dialyzed LDL prepared in non-EDTA- and EDTA (10 μmol/L)-containing buffers, an average of two measurements was taken. Results shown in Table 1⇑ are subject means using the average of two lag phase measurements. The Mann–Whitney test showed that the change in the lag phase observed after supplementation was not significantly different between the red wine extract and quercetin groups.

Lag phase measurements at baseline, after placebo treatment, and after the 5-week washout period were not different.

Changes in plasma lipids and ldl apoB concentrations during the study

Table 1⇑ shows that both red wine extract and quercetin treatment had no effect on plasma triglycerides and cholesterol (total, LDL, and HDL). There was no change in the total:HDL and LDL:HDL cholesterol ratios. The LDL apoB was decreased compared with baseline in the red wine extract-supplemented group and remained low throughout the study, including after the washout period. The LDL-cholesterol:apoB ratio was not changed in either group.

The results in Table 2⇓ show the hematological and hepatic biochemistry in the volunteers. The results remained constant throughout the study except the small changes in red blood cell count and serum γ-glutamyltransferase concentrations.

View this table:
  • View inline
  • View popup
Table 2.

Changes in blood biochemistry and liver enzymes of subjects over the study period.

Effect of supplementation on plasma micronutrients

Plasma ascorbic acid, tocopherol (α- and γ-), and retinol concentrations before and after supplementation are shown in Table 3⇓ . There was no significant change in any of the variables between time points. Likewise, there were no significant changes in the plasma and LDL (data not shown) carotenoids after red wine extract and quercetin supplementation (Figs. 1⇓ and 2). Both groups showed a trend in reduction of plasma retinol, tocopherol, and hydroxy-carotenoid concentrations following the placebo period, and this decrease was more apparent in alcohol drinkers. To investigate whether alcohol drinking habits had a significant effect on plasma micronutrients, a few extra subjects (two drinkers, four occasional drinkers, and two nondrinkers) were asked to take placebo supplements for 2 weeks, and alcohol drinkers were asked to limit their alcohol intake to not more than 1 unit/day. The results are shown in Table 4⇓ . After the placebo period, there were significant decreases in plasma retinol (P = 0.03, Wilcoxon rank test,) and lutein (P = 0.01) concentrations in the regular drinkers (n = 10). In occasional drinkers (n = 10), only retinol (P = 0.02) was significantly lower; there was no change in plasma micronutrients in nondrinkers (n = 9).

View this table:
  • View inline
  • View popup
Table 3.

Effect of red wine extract and quercetin supplementation on plasma micronutrient concentrations of the subjects over the study period.1

Figure 1.
  • Download figure
  • Open in new tab
Figure 1.

Changes in plasma carotenoids in the red wine extract-supplemented group (n = 11).

There were no significant changes in plasma carotenoids at any time point (not significant, Wilcoxon rank test). Bars, SD.

Figure 2.
  • Download figure
  • Open in new tab
Figure 2.

Changes in plasma carotenoids in quercetin-supplemented group (n = 10).

For each carotenoid, columns not sharing the same letter are significantly different at P <0.05 (Wilcoxon rank test). Bars, SD.

View this table:
  • View inline
  • View popup
Table 4.

Changes in fat-soluble micronutrients in drinkers and nondrinkers following the 2-week placebo treatment.1

Discussion

The day-to-day variation of the LDL lag phase has been reported to be low in unsupplemented volunteers (19)(20)(21). In the present study, each subject acted as his own control. Three measurements were done at time points when subjects were not receiving any treatment, i.e., baseline, placebo, and after a 5-week washout period, and there were no significant differences in the lag phase at these three time points (Table 1⇑ ). Several in vitro studies have shown an antioxidant effect of red wine and fractionated phenolic compounds on LDL oxidation (5)(11)(29)(30). The results of the present study show that supplementation of human subjects with alcohol-free red wine extract can inhibit oxidation of LDL ex vivo. Our results differed from two previously published reports. In one report, red wine extract (1 g/day, similar to the present study) inhibited LDL oxidation only in the samples dialyzed in the absence of EDTA in the dialysis buffer (9). The authors suggested that there was an inhibiting effect of EDTA in the copper-diene assay when polyphenols were examined. In our study, LDL oxidation was inhibited by the wine extract irrespective of the presence of EDTA in the buffer. The previous study (9) used a different dialysis technique: they used cassettes for the dialysis, and the dialysis buffer was not degassed or flushed with nitrogen. In our study, instead of cassettes, dialysis tubing was used and samples were dialyzed in a buffer flushed with nitrogen. It is possible that the different dialysis conditions may have contributed to the discrepancies between the two studies, but at present there is no other obvious explanation. In the second study, supplementation with alcohol-free red wine increased the antioxidant capacity of plasma but had no effect on LDL oxidation (31). The study protocol was similar to ours except that the polyphenol content of the wine extract was different. There were similar amounts of flavonols and anthocyanins, but the catechin and proanthocyanin concentrations were one-half of those used in our study. Both catechins and proanthocyanin have been reported to show antioxidant properties in vitro (32)(33), and the differences in their concentrations may have contributed to the differences in the findings from our study with those of Carbonneau et al. (31).

Quercetin, a major flavonol in red wine, when given on its own also inhibited LDL oxidation. The red wine extract and quercetin supplements had the same effect on the lag phase. The red wine extract contained 1.7 mg of quercetin as glycoside and 1.8 mg as aglycone. It has been reported that only 24% of the aglycone is absorbed from onions (24). Provided the same is true for pure supplements, then ∼7.2 mg of quercetin from the pure supplements and 1.2 mg from the red wine extract would have been absorbed. The lag phase was raised by 23% in the red wine extract-supplemented group and 27% in the quercetin-supplemented group. The red wine extract, however, also contained other phenolic components, such as resveratol, procyanidins, anthocyanins, and catechins (see Materials and Methods for detailed composition), all of which have been reported to show antioxidant properties (17)(18)(32)(33)(34). The results of the present study, therefore, suggest that quercetin may not be the only protective component of the red wine.

Both red wine extract and quercetin supplementation failed to have an effect on plasma lipid concentrations. This, however, could be attributable to the fact that most subjects in the present study were normolipidemic. Previous studies have shown that flavonoids, in particular quercetin, can lower lipid concentrations in hyperlipidemic rats (35). Preliminary studies in our laboratory have suggested that red wine extract can lower plasma cholesterol, particularly LDL-cholesterol, but only in hyperlipidemic subjects (>6.5 mmol/L cholesterol). However, these observations require further confirmation through carefully planned studies.

In contrast to a previous report (31), we did not find any increase in plasma or LDL (data not shown) α-tocopherol and carotenoid concentrations after quercetin or wine extract supplementation. Indeed, there was evidence of a decrease in these analytes, particularly in those who regularly drank alcohol before the study and reduced their alcohol intake to <1 unit/day. In those previously consuming alcohol, there was a significant reduction in plasma lutein and retinol concentrations. It is interesting to note that in a recent Scottish Health Survey (36), people who drank alcohol had significantly higher retinol concentrations than nondrinkers, supporting the observation that alcohol consumption may influence plasma tocopherol, lutein, and retinol. Only polar nutrients were affected by alcohol consumption. The effect of alcohol might be related to increased absorption of these nutrients through a solvating effect of alcohol. However, this would be most surprising in the case of retinol because plasma concentrations are homeostatically controlled (37), unless alcohol affects the synthesis or transport of retinol-binding protein, thereby influencing plasma retinol concentrations indirectly.

In summary, the consumption of alcohol-free red wine can increase the antioxidant capacity of LDL but has no effect on plasma vitamin A, C, and E and carotenoid concentrations. It is, however, noteworthy that because alcohol withdrawal was found to have a significant effect on some of the plasma fat-soluble vitamins, future studies in which subjects are asked to refrain from alcohol consumption during the course of the study should take into account possible effects of alcohol withdrawal on plasma vitamin concentrations.

Acknowledgments

This study was funded by The Howard Foundation, Cambridge, UK. We would like to thank the Causeway Laboratories, Coleraine, UK, for undertaking the lipid analysis, and Lilia Burns for taking blood samples for the present study.

  • © 2000 The American Association for Clinical Chemistry

References

  1. ↵
    Steinberg D, Parthasarthy S, Carew TE, Khoo JC, Witzum JL. Beyond cholesterol: modification of LDL that increases its atherogenecity. New Engl J Med 1989;320:915-924.
    OpenUrlCrossRefPubMed Order article via Infotrieve
  2. ↵
    Diehl AK, Fuller JH, Mattock MB, Salter AM, El-Gohari R, Keen H. The relationship of high-density lipoprotein subfractions to alcohol consumption, other lifestyle factors and coronary heart disease. Atherosclerosis 1988;69:145-153.
    OpenUrlCrossRefPubMed Order article via Infotrieve
  3. ↵
    Gaziano YM, Buring JE, Breslow JL, Goldhaber SZ, Rosner B, van den Burgh M. Moderate alcohol intake increased levels of high density lipoprotein and its subfractions and decreased risk of myocardial infarction. N Engl J Med 1993;329:1829-1833.
    OpenUrlCrossRefPubMed Order article via Infotrieve
  4. ↵
    De Whalley CV, Rankin SM, Hoult JRS, Jessup W, Leake DS. Flavonoids inhibit the oxidative modification of low-density lipoproteins by macrophages. Biochem Pharmacol 1990;39:1743-1745.
    OpenUrlCrossRefPubMed Order article via Infotrieve
  5. ↵
    Frankel EN, Kanner J, German JB, Parks E, Kinsella JE. Inhibition of oxidation of human low-density lipoprotein by phenolic substances in red wine. Lancet 1993;341:454-457.
    OpenUrlCrossRefPubMed Order article via Infotrieve
  6. ↵
    Fuhrman B, Lavy A, Aviram M. Consumption of red wine with meals reduces the susceptibility of human plasma and low-density lipoprotein to lipid-peroxidation. Am J Clin Nutr 1995;61:549-554.
    OpenUrlAbstract/FREE Full Text
  7. ↵
    Kondo K, Matsumoto A, Kurata H, Tanakashi H, Koda H, Amachi T, Itakura H. Inhibition of oxidation of low-density lipoprotein with red wine. Lancet 1994;344:1152.
    OpenUrlPubMed Order article via Infotrieve
  8. ↵
    DeRijke YB, Demacker PNM, Assen NA, Sloots LM, Katan MB, Stalenhoef AFH. Red wine consumption does not affect oxidizability of low-density lipoproteins in volunteers. Am J Clin Nutr 1996;63:329-334.
    OpenUrlAbstract/FREE Full Text
  9. ↵
    Nigdikar SV, Williams NR, Griffin BA, Howard AN. Consumption of red wine reduces the susceptibility of low-density lipoproteins to oxidation in vivo. Am J Clin Nutr 1996;68:258-265.
    OpenUrlAbstract/FREE Full Text
  10. ↵
    Miyagi Y, Miwa K, Inoue H. Inhibition of human low-density lipoprotein oxidation by flavonoids in red wine and grape juice. Am J Cardiol 1997;80:1627-1631.
    OpenUrlCrossRefPubMed Order article via Infotrieve
  11. ↵
    AbuAmsha R, Croft KD, Puddy IB, Proudfoot JM, Beilin LJ. Phenolic content of various beverages determines the extent of inhibition of human serum and low-density-lipoprotein oxidation in-vitro. Identification and mechanism of action of some cinnamic acid-derivatives from red wine. Clin Sci 1996;91:449-458.
    OpenUrlPubMed Order article via Infotrieve
  12. ↵
    Roggero JP, Archier P, Coen S. Chromatography of phenolics in wine. ACS Symposium Series 1997;661:6-11.
    OpenUrl
  13. ↵
    Goldberg DM, Tsang E, Karumanchiri A, Soleas GJ. Quercetin and p-coumaric acid concentrations in commercial wines. Am J Enol Vitic 1998;49:142-151.
    OpenUrlAbstract/FREE Full Text
  14. ↵
    Sato M, Ramarathan N, Suzuki Y, Ohkubo T, Takeuchi M, Ochi H. Varietal differences in the phenolic content and superoxide radical scavenging potential of wines from different sources. J Agric Food Chem 1996;44:37-41.
    OpenUrlCrossRef
  15. ↵
    Waterhouse AL, Teissedre PL. Levels of phenolics in California varietal wines. ACS Symposium Series 1997;661:12-23.
    OpenUrl
  16. ↵
    Ioku K, Tsushida T, Takai Y, Nakatani N, Terao J. Antioxidative activity of quercetin and quercetin monoglucosides in solution and phospholipid-bilayers. Biochim Biophys Acta 1995;1234:99-104.
    OpenUrlPubMed Order article via Infotrieve
  17. ↵
    Rice-Evans CA, Miller NJ, Papanga G. Antioxidant properties of phenolic compounds. Trends Plant Sci 1997;2:152-159.
    OpenUrlCrossRef
  18. ↵
    Zou JG, Huang YZ, Chen Q, Wei EH, Hsieh TC, Wu JM. Resveratrol inhibits copper ion-induced and azo compound-initiated oxidative modification of human low density lipoproteins. Biochem Mol Biol Int 1999;47:1089-1096.
    OpenUrlPubMed Order article via Infotrieve
  19. ↵
    Abbey M, Belling GB, Noakes M, Hirata F, Nestel PJ. Oxidation of low-density lipoproteins-Intraindividual variability and the effect of dietary linoleate supplementation. Am J Clin Nutr 1993;57:391-398.
    OpenUrlAbstract/FREE Full Text
  20. ↵
    van de Vijver LP, van Duyvenvoorde W, Buytenhek R, van der Laarsee A, Kardinaal AFM, van der Berg H, et al. Seasonal variation in low-density lipoprotein oxidation and antioxidant status. Free Radic Res 1997;27:89-96.
    OpenUrlPubMed Order article via Infotrieve
  21. ↵
    Chopra M, Kavanagh S, Fitzsimons P, Thurnham DI. Variations in the serum cholesterol, ferric reducing ability of plasma and LDL lagphase in untreated human subjects [Abstract]. Proc Nutr Soc 2000;59:21a.
    OpenUrl
  22. ↵
    Hertog MGL, Kromhout D, Aravanis C, Blackburn H, Buzina R, Fidanza F, et al. Flavonoid intake and long term risk of coronary heart disease and cancer in the seven country study. Arch Intern Med 1995;155:381-386.
    OpenUrlCrossRefPubMed Order article via Infotrieve
  23. ↵
    Knekt P, Jarvinen R, Reunanen A, Maatela J. Flavonoid intake and coronary mortality in Finland: a cohort study. Br Med J 1997;312:478-481.
    OpenUrlAbstract/FREE Full Text
  24. ↵
    Hollman PCH, De Veris JH, Van Leeuwen SD, Mengelers MJB, Katan MB. Absorption of dietary quercetin glycosides and quercetin in healthy ileostomy volunteers. Am J Clin Nutr 1995;62:1276-1282.
    OpenUrlAbstract/FREE Full Text
  25. ↵
    Chung BH, Segrest JP, Ray MJ, Brunzell JD, Hokanson JE, Krauss RM, et al. Single vertical spin density gradient ultracentrifugation. Methods Enzymol 1986;128:181-209.
    OpenUrlCrossRefPubMed Order article via Infotrieve
  26. ↵
    Puhl H, Waeg G, Esterbauer H. Methods to determine oxidation of low density lipoproteins. Methods Enzymol 1994;233:441-456.
    OpenUrlPubMed Order article via Infotrieve
  27. ↵
    Heiliger F. Measurement of plasma ascorbate. Curr Sep 1980;2:368-372.
    OpenUrl
  28. ↵
    Thurnham DI, Smith E, Flora PS. Concurrent liquid chromatography assays of retinol, α-tocopherol, β-carotene, lycopene and β-cryptoxanthin in plasma with tocopherol acetate as internal standard. Clin Chem 1988;34:377-381.
    OpenUrlAbstract/FREE Full Text
  29. ↵
    Kerry NL, Abbey M. Red wine and fractionated phenolic compounds prepared from red wine inhibit low density lipoprotein oxidation in vitro. Atherosclerosis 1997;135:93-102.
    OpenUrlCrossRefPubMed Order article via Infotrieve
  30. ↵
    Gardner PT, McPhail DB, Crozier A, Duthie GG. Electron spin resonance (ESR) spectroscopic assessment of the contribution of quercetin and other flavonols to the antioxidant capacity of red wine. J Sci Food Agric 1999;79:1011-1014.
    OpenUrlCrossRef
  31. ↵
    Carbonneau MA, Leger CL, Monnier L, Bonnet C, Michel F, Fouret G, et al. Supplementation with wine phenolic compounds increases the antioxidant capacity of plasma and vitamin E of low-density lipoprotein without changing the lipoprotein Cu2+ oxidisability. Possible explanation by phenolic location. Eur J Clin Nutr 1997;51:682-690.
    OpenUrlCrossRefPubMed Order article via Infotrieve
  32. ↵
    Kondo K, Kurihara M, Miyata N, Suzuki T, Toyoda M. Mechanistic studies of catechins as antioxidants against radical oxidation. Arch Biochem Biophys 1999;362:79-86.
    OpenUrlCrossRefPubMed Order article via Infotrieve
  33. ↵
    Bagchi D, Garg A, Krohn RL, Bagchi M, Tran MX, Stohs SJ. Oxygen free radical scavenging abilities of vitamin C and E and a grape seed proanthocyanidin extract in vitro. Res Commun Mol Pathol Pharmacol 1998;95:179-189.
    OpenUrl
  34. ↵
    Ghiselli A, Nardini M, Baldi A, Scaccini C. Antioxidant activity of different phenolic fractions separated from an Italian red wine. J Agric Food Chem 1998;46:361-367.
    OpenUrlCrossRefPubMed Order article via Infotrieve
  35. ↵
    Yugarani T, Tan BKH, Teh M, Das NP. Effects of polyphenolic natural products on the lipid profiles of rats fed high fat diets. Lipids 1992;27:181-186.
    OpenUrlCrossRefPubMed Order article via Infotrieve
  36. ↵
    Bost L, Dong W, Primatesta P. Blood analytes. Dong W Erens B eds. Scottish Health Survey, 1995 1995;Vol. 1:333-353 Her Majesty’s Stationary Office Edinburgh, UK. .
  37. ↵
    Willett WC, Stampfer MJ, Underwood BA, Taylor JO, Hennechens CH. Vitamin A, E, carotene. Effect of supplementation on their plasma levels. Am J Clin Nutr 1983;38:559-566.
    OpenUrlAbstract/FREE Full Text
View Abstract
PreviousNext
Back to top

In this issue

Clinical Chemistry: 46 (8)
Vol. 46, Issue 8
August 2000
  • Table of Contents
  • Index by author
Print
Share
Nonalcoholic Red Wine Extract and Quercetin Inhibit LDL Oxidation without Affecting Plasma Antioxidant Vitamin and Carotenoid Concentrations
Mridula Chopra, Patricia E.E. Fitzsimons, John J. Strain, David I. Thurnham, Alan N. Howard
Clinical Chemistry Aug 2000, 46 (8) 1162-1170;
del.icio.us logo Digg logo Reddit logo Twitter logo CiteULike logo Facebook logo Google logo Mendeley logo
Article Alerts
Sign In to Email Alerts with your Email Address
Citation Tools
Nonalcoholic Red Wine Extract and Quercetin Inhibit LDL Oxidation without Affecting Plasma Antioxidant Vitamin and Carotenoid Concentrations
Mridula Chopra, Patricia E.E. Fitzsimons, John J. Strain, David I. Thurnham, Alan N. Howard
Clinical Chemistry Aug 2000, 46 (8) 1162-1170;

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero

  • Tweet Widget
  • Facebook Like
  • Google Plus One

Jump to section

  • Article
    • Abstract
    • Materials and Methods
    • Results
    • Discussion
    • Acknowledgments
    • References
  • Figures & Data
  • Info & Metrics
  • PDF

Related Articles

Cited By...

More in this TOC Section

  • Coffee Consumption and Circulating B-Vitamins in Healthy Middle-Aged Men and Women
  • Influence of Pancreatic Status and Sex on Polyunsaturated Fatty Acid Profiles in Cystic Fibrosis
  • Decreased Serum Retinol Is Associated with Increased Mortality in Renal Transplant Recipients
Show more Nutrition

Similar Articles

Subjects

  • SUBJECT AREAS
    • Nutrition

Options

  • Home
  • About
  • Articles
  • Information for Authors
  • Resources
  • Abstracts
  • Submit
  • Contact
  • RSS

Other Publications

  • The Journal of Applied Laboratory Medicine
Footer logo

© 2019 American Association for Clinical Chemistry

Powered by HighWire