Changes in Cardiovascular Risk Factors Associated with Wine Consumption in Intervention Studies in Humans

Lipid Factors 

Ethanol-mediated high-density lipoprotein (HDL) cholesterol elevation is generally considered the main mechanism explaining the benefits of moderate alcohol consumption, with Rimm et al (2) estimating that HDL explains one half of the beneficial effects. In a meta-analysis conducted by the authors (3), calculations suggested that 30 g of alcohol a day (approximately 320 mL of wine) would cause an average increase of 8.3% in HDL levels. We conducted an intervention study on 44 healthy young male volunteers who received a high-fat diet, rich in monounsaturated or polyunsaturated fatty acids and supplemented isocalorically with either a soft drink, 250 mL of white wine, 250 mL of red wine, or fruits and vegetables for 3-week periods each. We observed increases in HDL levels ranging between 4% and 18% among those who received wine, which was greater than that seen with fruits and vegetables; red wine appeared to be slightly better than white wine for this purpose.

In a recent Internet-based intervention to promote the Mediterranean diet in Scotland, increases in HDL levels were observed among those who followed it; these increases were attributed to increased consumption of vegetables, fruits, and legumes, as well as the monounsaturated fatty acid/saturated fatty acid ratio of the diets (4). Increased levels of apolipoprotein A-1 have also been observed after moderate alcohol consumption, particularly during the transient postprandial phase (5). The mechanism through which HDL exerts its beneficial effects has not been fully elucidated; experimental evidence supports reverse cholesterol transport mediated by HDL, but the results are not consistent (5). An additional explanation for the antiatherogenic effects of HDL is its potent endothelial nitric oxide synthase (eNOS)–inducing activity, which is apparently mediated by scavenger receptors class B type I (SR-BI) and would explain its premenopausal estrogen-dependent protective effects (6).

A negative consequence of alcohol consumption on plasma lipids is the increase observed in triglycerides. Although fasting triglyceride levels have been shown to increase in some experimental observations, the change is minor compared with increases in HDL, particularly when alcohol consumption is kept below 30 g/d.

Hemostasis 

The beneficial effects of wine are reflected at many levels of the hemostatic process, including primary hemostasis, fibrinolysis, coagulation, and thrombosis. Almost all the changes described are protective and, after changes in HDL, constitute the second main explanation for the lower risk of CHD associated with moderate alcohol consumption (2). The effects of alcohol on hemostasis have been reviewed recently (7). In addition to changes induced after 1 month of daily consumption of 240 mL of red wine (8), studies revealed that subjects on a high-fat diet showed increases in procoagulant fibrinogen (22%), factor VIIc (9%) and factor VIIIc (4%). Decreases in the natural anticoagulants antithrombin III (3%), protein C (11%), protein S (6%), and plasminogen activator inhibitor-1 (20%) were also observed. In contrast, subjects on a Mediterranean diet showed less of an increase in fibrinogen (4%), antithrombin III (5%), protein C (3%), and protein S (2.7%), and decreases in factor VIIIc (9%) and plasminogen activator inhibitor-1 (21%). In both diets, red wine supplementation resulted in decreased plasma fibrinogen and factor VIIc, and increased tissue plasminogen activator antigen and plasminogen activator inhibitor-1 antigen. Divergent effects were observed with wine consumption on antithrombin III. Whereas the high-fat diet groups showed a 10% decrease, there was a slight increase in the Mediterranean diet group. These results confirm those described in other studies and emphasize the important role of the diet in the modulation of the biological effects of alcohol. Clearly, there is synergy between the Mediterranean diet and wine consumption for the prevention of cardiovascular disease.

With regard to thrombosis, observations in animal models suggest that in addition to the antithrombotic effect of alcohol, wine phenolics, per se, also play an important role, which is mediated by the enzyme eNOS synthase. In human studies the available evidence supports a principal role for ethanol in the changes observed with wine administration (9). In contrast, wine phenol antioxidants apparently play a major role in the protective effects of nitric oxide, perhaps an explanation for the modulation by the Mediterranean diet of the changes in hemostasis associated with moderate alcohol consumption.

Inflammation 

There is growing evidence that inflammation plays a central role at various stages of the atherosclerotic process (10). Phenolic compounds in wine have several biological activities that make them potential therapeutic agents for cardiovascular disease, as recently reviewed by Curin and Andriantsitohaina (11). Cyclooxygenase, lipoxygenase, prostaglandin biosynthesis, monocyte adhesion and nuclear factor κB activation are among the inflammatory responses modified by phenolics. Notwithstanding this evidence, intervention studies with wine and other alcoholic beverages point to a central role of ethanol in the anti-inflammatory responses observed. A prospective randomized crossover trial compared the effects of red wine and gin (12) and concluded that both wine and gin exert anti-inflammatory effects by reducing plasma fibrinogen and interleukin 1α levels; wine had the additional effect of decreasing hs-C-reactive protein, as well as monocyte and endothelial adhesion molecules. The effects of red and white wine were compared by Williams et al (13), who found that plasma interleukin 6 was elevated after the consumption of either, a result the authors correlated with blood alcohol levels.

Beer also exerts anti-inflammatory effects, and intervention studies show a decrease in plasma C-reactive protein and fibrinogen levels (14). These results clearly suggest that alcohol is responsible for several anti-inflammatory changes observed after moderate drinking and that wine phenolics may have additional anti-inflammatory activities. Among the effects attributed to wine phenolics are the increased level of ω-3 fatty acids after wine consumption, the anti-inflammatory properties of which have been well described (15).

Endothelial Function 

Endothelial dysfunction is an early event in the development of atherosclerosis. It accompanies most of the risk factors that result in atherosclerosis development and is present along the various stages of the disease. Indeed, endothelial dysfunction seems to be an efficient marker of the composite effect of the various factors involved in predisposition to atherosclerosis, as well as a valid marker for monitoring changes in these risk factors. Nevertheless, its value as a surrogate marker for atherosclerotic cardiovascular risk has not been established firmly, probably because the methods employed for its clinical evaluation are still too cumbersome for it to be included in the extensive prospective studies needed 16, 17.

We have shown that a high-fat diet induces endothelial dysfunction and that red wine counteracts this effect (18), a phenomenon apparently specific to red wine (19). In a randomized controlled intervention study performed in healthy, normotensive, moderate-drinking men, Zilkens et al (20) did not find changes in endothelial function measured by flow-mediated brachial artery dilatation. However, we have shown that clear-cut results are observed after 4 weeks of red wine consumption in volunteers who received a high-fat diet, known to depress endothelial function, but not in those who received a Mediterranean diet (18). The flow-mediated dilatation procedure to measure endothelial function is very sensitive. In acute experiments it has been shown that smoking a single cigarette will decrease endothelial function for approximately 60 minutes, a change prevented when red wine or dealcoholized red wine is consumed while smoking (21).

In contrast to other risk factors, the correction of endothelial dysfunction after wine administration seems dependent on wine phenolics, an effect attributed to their antioxidative properties and their direct effects on eNOS. In nonacute experiments, ethanol may have a direct effect on endothelial function. In fact, studies to explore the mechanism of chronic ethanol-induced acute respiratory distress syndrome have shown that under experimental conditions long-term ethanol stimulation modulates vascular endothelial function and increases nitric oxide production by increasing eNOS protein (22).

Wine, ω-3 fatty acids, and the Mediterranean diet in general protect endothelial function. Furthermore, the pathogenesis of metabolic syndrome has been attributed to endothelial dysfunction, an attractive hypothesis in the search for the biochemical explanation of this syndrome, as well as in defining strategies to reduce it and to monitor the efficacy of corrective measures (23).

Blood Pressure 

There is substantial evidence that demonstrates a positive relationship between alcohol consumption and blood pressure. Alcohol consumption of 3 or more standard drinks per day is associated with and predictive of hypertension. Routine screening for excessive alcohol consumption should therefore have a major impact on reducing the prevalence of hypertension among the general population (24). The response to a high dose of alcohol is biphasic: first vasodilation occurs, followed by a pressor effect, a hemodynamic pattern that should be considered when blood pressure changes are not monitored continuously (25). Zilkens et al. found that both beer and red wine (in doses of approximately 40 g of alcohol per day) increase systolic blood pressure by 1.9 and 2.9 mm Hg, respectively, suggesting that red wine does not decrease blood pressure (20).

In contrast, Thadhani et al. (26) examined the association between alcohol consumption and the subsequent risk of hypertension in 70,891 women ranging from 25 to 42 years of age and found a J-shaped curve, with light drinkers demonstrating a modest decrease in risk. In addition to dose, meals may also affect the hypertensive effect of alcoholic beverages; an elevated risk for hypertension was found by Stranges et al. (27) to occur in subjects consuming alcohol without meals. In an intervention study with red wine (including 53 women drinking 11.4 to 14.2 g of ethanol per day and 42 men drinking 22.8 to 28.4 g/d), we found that after 6 weeks, systolic and diastolic pressure values did not change significantly as compared with those in a control group that did not consume wine. In another intervention study, involving elderly people, administered the same doses, wine had a slight hypotensive effect. Finally, in a third intervention study done with young male volunteers, both white wine (at a dosage of 23.3 g of alcohol per day) and fruits and vegetables showed a mild hypotensive effect, not apparent with red wine.

Overall, it appears that moderate consumption of wine, defined herein as less than 30 g of alcohol per day for males and half that dose for females, is associated either with a slight hypotensive response or with no change in blood pressure. The results from a prospective study of moderate alcohol consumption in young women suggests that the same relationship observed for wine is also present for other alcoholic beverages (26).

Anthropometric Parameters 

Waist circumference, more than body mass index, is being recognized as a marker of intra-abdominal fat content and the metabolic syndrome. Vadstrup et al (28) examined the long-term association between the amount and type of alcohol consumed and subsequent waist circumference among a sample of men and women from the Copenhagen City Heart Study (28). Their conclusions were that consumption of beer and spirits was associated with the development of high waist circumference, whereas moderate-to-high wine consumption apparently had the opposite effect. These results are in agreement with our proposition that red wine, through eNOS enhancement, should help in the control and prevention of the metabolic syndrome (23).

In a recent intervention involving 53 women drinking red wine at a dose equivalent to 11.4 to 14.2 g of ethanol per day and 42 men drinking 22.8 to 28.4 g/d, we found that compared with basal values, waist circumference decreased 1.0 cm (p < 0.0001) after 6 weeks of wine consumption; a similar decrease of 1.3 cm (p < 0.0001) was observed for volunteers who did not drink wine. The conclusion is that wine consumption, in this short-term 6-week intervention, did not increase waist circumference.

Oxidative Stress 

Intervention studies using red wine have shown that wine phenolics are, to a certain degree, absorbed and that either the original compounds or their metabolites exert antioxidant effects. Several studies have shown protection of low-density lipoprotein (LDL) cholesterol against oxidation in vitro. Tsang et al. (29) gave red wine to volunteers for 2 weeks and found a decrease in conjugated dienes and in TBARS in copper-oxidized LDL (29); they were able to detect metabolites of wine phenolics in plasma. Their conclusion, similar to that of others doing similar interventions, is that moderate consumption of red wine exerts potential protective effects related to phenolic antioxidants.

In an intervention study in which young male volunteers were given Mediterranean or occidental (high-fat) diets accompanied by 240 mL of red wine daily over a 4-week period, total phenols in plasma were elevated after wine consumption. An increase in total plasma antioxidant capacity was observed, both in those on the Mediterranean diet and in those on the occidental diet, and for those who received wine with either diet (30). A concurrent decrease in leukocyte DNA oxidation was also observed, both with the Mediterranean diet and with wine.

In another similar intervention study, we used white wine, red wine, or a supplement of fruits and vegetables that provided the same caloric count as the wine. We found that red wine exerts marked protection on DNA oxidation, a 56.5% decrease in 8-OHdG. A significant effect was also observed with diet supplementation by fruits and vegetables, a 36.4% decrease, and a smaller (12%) decrease was observed with white wine (3).

In another intervention, performed with elderly male and female volunteers, we found the same degree of protection of DNA by red wine consumption in both groups. This result is particularly interesting, as the women received one half of the dosage of wine of men (12g ethanol per day vs. 24 g ethanol per day). In an intervention study, Natella et al. (31) measured the wave of plasma lipoperoxides associated with postprandial hyperlipemia; they found that 250 mL of wine with a meal almost completely prevented the increase in plasma lipoperoxides, an effect attributed by the authors to antioxidant protection in the lumen of the intestine (31).

Homocysteine. Plasma homocysteine levels are strong independent biomarkers for CHD-related death (32). It has been reported that 40g daily of alcohol in the form of red wine or spirits, but not beer, increases homocysteine levels (33). These observations should take into consideration that there is a U-shaped relation between alcohol consumption and homocysteine concentration, with an average of less than 14 g daily being associated with lower homocysteine concentrations (34).