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Is Red Wine Good for Your Heart?
September 24, 2007
What is Coronary Heart Disease?
Coronary heart disease (CHD) is defined as a failure of any part or all of the heart. CHD often results from plaque build up in the arteries that provide blood to the myocardium, or heart muscle. This process of plaque build-up in the arteries is called arteriosclerosis. Many individuals show no symptoms of CHD until the build up has become so great that blood flow to the heart muscle is almost completely blocked, which can result in a heart attack (http://heartdiseases.us/).
Does drinking red wine protect against heart disease?
A number of websites and popular media advertise that individuals who drink red wine in moderation have lower rates of coronary heart disease than those who do not (http://www.mayoclinic.com/health/red-wine/HB00089). Indeed, sources announce that drinking one to two glasses of red wine lowers the risk of coronary heart disease for individuals of middle age anywhere from 20% to 50%. Several internet sources also claim that drinking red wine in moderation may prevent additional heart attacks in patients who already suffer from CHD (http://www.healthcastle.com/redwine-heart.shtml).
How does red wine prevent heart disease?
Internet sources offer several possible mechanisms by which red wine may prevent heart disease. Most websites assert that it is most likely a combination of these mechanisms that gives red wine its protective power but that it is not completely clear yet how these mechanisms work together to prevent CHD. For example, most sources assert that red wine works in the blood to raise HDL, or “good” cholesterol, and lower LDL, or “bad” cholesterol (http://www.healthcastle.com/redwine-heart.shtml). Indeed, moderate use of alcohol in the form of red wine or other alcoholic beverages is advertised as raising HDL cholesterol and also lowering blood pressure, inhibiting clots, and helping prevent arterial damage (http://www.mayoclinic.com/health/red-wine/HB00089).
In addition, red wine is thought to gain some of its protective power from the large amount of antioxidants found in red wine (http://www.healthcastle.com/redwine-heart.shtml). In general, sources point to antioxidants as having a protective effect by preventing the action of free radicals in the body. Free radicals are chemicals that damage cells through the oxidation of cell membranes. In particular, when LDL particles are attacked by free radicals, they become dangerous and help stimulate the atherosclerosis that leads to CHD and strokes. Therefore, the high concentration of antioxidants in red wine may make it particularly beneficial (http://ezinearticles.com/?The-Truth-About-Red-Wine-and-Heart-Disease&id=48582).
More specifically, red wine is the source of antioxidants called polyphenols, particularly resveratrol and flavanoids, which many websites claim may work to prevent blood clots and reduce the arterial damage caused by fat deposits. (http://www.healthcastle.com/redwine-heart.shtml). For example, resveratrol is found in grapes and exits in a higher quantity in red wine as compared to other alcoholic beverages because of the longer fermentation process. Some websites claim that resveratrol is thought to have the potential to prevent damage to blood vessels, lower levels of LDL cholesterol, and prevent blood clots (http://www.mayoclinic.com/health/red-wine/HB00089). In addition, the polyphenols called flavanoids found in red wine are advertised as preventing plaque build up in the arteries. Sources also claim that polyphenols can prevent blood clots by inhibiting the action of platelets, or the blood cells that aid in the formation of clots. One source even goes so far as the claim that the antioxidants in red wine may have a protective effect against cancer by preventing oxidation caused by free radicals, but the source asserts that this idea requires more research (http://seniorjournal.com/NEWS/Health/5-03-18WinePolyphenols.htm).
Websites also offer several bits of inconsistent information about the benefits of red wine. Some websites claim that the high amount of antioxidants in red wine as compared to other alcoholic beverages may be at least part of the reason that red wine is thought to provide more protection against CHD than other alcoholic beverages (http://www.sciencedaily.com/releases/2005/03/050325222705.htm). However, other websites deny that increased benefits from drinking red wine as compared to beer or liquor exist at all (http://www.mayoclinic.com/health/red-wine/HB00089). Furthermore, some sources point to the fact that the decreased risk for heart disease associated with red wine could be affected by other lifestyle factors such as physical activity and a nutritious diet. One thing is clear: although these proposed ideas all seem plausible, most of the websites agree that more research is needed in order to specifically pinpoint how red wine affects the cardiovascular system (http://www.americanheart.org/presenter.jhtml?identifier=4422).
Where did this idea come from?
The idea that red wine may lesson the risk of cardiovascular disease was sparked by the discovery of what is called “The French Paradox” in 1992. “The French Paradox” refers to the discovery that southern France, despite individual diets that are high in saturated fats, tends to have a much lower mortality rate from CHD than the United States and many other regions in Europe (http://www.sciencedaily.com/releases/2005/03/050325222705.htm). When researchers noticed that individuals in southern France tend to prefer red wine to beer and spirits at that they use wine to accompany meals rather than in excessive amounts, they proposed that moderate consumption of red wine could be at least partially responsible for the low rate of CHD (http://www.americanheart.org/presenter.jhtml?identifier=4422).
Should you start drinking red wine to prevent heart disease?
Most websites advertise that they agree with doctors’ attitudes that if patients who already drink in moderation continue to do so they will most likely experience the protective benefits of red wine. However, they are wary to encourage individuals who do not drink to begin drinking as a mode for decreasing the risk of CHD (http://www.mayoclinic.com/health/red-wine/HB00089). In support of this caution, websites warn readers of the multiple negative effects drinking alcohol can have. Drinking red wine and other alcoholic beverages in excess has been associated with an increase in triglycerides, weight gain, increased risk for cancer, stroke, cardiac arrhythmia, and even sudden cardiac death (http://www.healthcastle.com/redwine-heart.shtml). Since, there is no way to completely predict which individuals are susceptible to developing alcoholism, doctors worry it is dangerous to encourage drinking in patients when it could turn into dangerous and destructive patterns. Furthermore, websites remind readers to abstain from alcohol if taking aspirin and or if pregnant. Children of women who consume alcohol while pregnant are at high risk for fetal alcohol syndrome and birth defects (http://www.americanheart.org/presenter.jhtml?identifier=4422).
Furthermore, many websites point to the fact that many of the antioxidants thought to give red wine its ability to reduce the risk of CHD are also found in grapes, berries and peanuts. Therefore, it is proposed that these foods may be a less harmful substitute for alcohol (http://www.mayoclinic.com/health/red-wine/HB00089). Finally, exercising regularly and having a diet that is high in fruits and vegetables also reduce the risk of CHD without the risk factors of drinking alcohol (http://www.healthcastle.com/redwine-heart.shtml).
Ultimately, the crucial feature of any website’s claim that red wine helps to reduce the risk of CHD is the importance drinking red wine in moderation. The majority of sources defined moderation as one glass of wine a day for women and two for men (http://www.mayoclinic.com/health/red-wine/HB00089). Therefore, drinking red wine in moderation is essential in experiencing the benefits of red wine while avoiding the more dangerous effects of alcohol and reducing the risk of developing alcoholism (http://www.americanheart.org/presenter.jhtml?identifier=4422).
Where does the information on the internet come from?
The information found on the internet pertaining to the relationship between red wine and CDH comes from a variety of sources. The majority of these sources are legitimate. For example, much of the information present in this document comes from websites from the Mayoclinic and American Heart Association, both of which are organizations designed to educate the general public about health issues. The information presented by these organizations is supported by clinical and scientific findings. These educational websites use scientific terminology, present information supported by scientific studies, and offer information that is still being researched as possibility rather than fact. Websites that were not from nationally recognized organizations most often targeted specific populations. For example, one website that targeted senior citizens represented a slightly more biased view of the issue and included information that would be most pertinent to that specific age group. Another website targeted individuals who had already suffered from heart disease; this website was the only that criticized doctors unwillingness to encourage patients to use drinking wine as a preventative measure for CHD.
What does scientific literature say?
Specific studies and scientific reviews support the idea that moderate drinking of red wine lowers an individual’s risk for heart disease, but the exact methods by which this occurs are still being researched. Indeed, one review stated that when 51 epidemiological studies were combined, data suggested that the risk of CHD decreased when individuals consumed zero to two alcoholic beverages a day by approximately 20%. This review found that the benefits seemed to be most prevalent in middle-aged individuals and were present for healthy individuals as well as those with previous incidences of CHD (Szmitko & Subodh, 2005). Similarly, another review stated that at least twelve studies demonstrated consuming one to two drinks per day reduces the risk of CHD 30% to 50%. This review recognized that multiple observational studies have shown a J-shaped curve when observing the relationship alcohol and CHD: studies show that the lowest levels of mortality from CHD occur in individuals drinking one to two alcoholic beverages a day, but mortality from CHD increases rapidly for individuals drinking three or more alcoholic beverages a day. In most studies, this relationship was found to be independent of potential confounding variables such as diet or exercise, and the data was similar across gender and ethnicity (Pearson, 1996). It is crucial to remember that all of these studies are merely observational in nature. Although they support claims that red wine and alcohol reduce the risk of CDH, no specific clinical trial on this issue has been conducted.
Furthermore, scientific research has found that 1 to 2 drinks per day of any alcohol increases levels of HDL cholesterol, which can remove some of the LDL cholesterol in the blood stream (Szmitko & Subodh, 2005). One review states that analysis of recent studies suggests that at least half of alcohol’s protective effect stems from its ability to increase levels of HDL cholesterol in the blood (Pearson, 1996).
Several studies suggest that polyphenolic compounds, including the flavanoids and resveratrol found in red wine, may prevent CHD by limiting atherosclerosis. Specifically, a review in the journal of the American Heart Association states that both alcohol and polyphenols appear to prevent atherosclerosis by promoting the formation of nitric oxide, which protects against vascular injury, inhibits inflammatory cells from attaching to vessel walls, and keeps platelets from clotting. Studies in animals have found that the antioxidants in wine limit early plaque formation in the blood vessels (Szmitko & Subodh, 2005).
Other studies have shown that both the alcohol and polyphenolic compounds in red wine have anticlotting properties, although the exact methods are unknown (Szmitko & Subodh, 2005). A review of several studies suggests that alcohol may cause blood to clot less or enhance the body’s ability to break up existing clots. So far, the recent studies looking into both how wine affects clotting properties of the blood as well as how the antioxidants found in wine are beneficial have produced inconsistent evidence. Further research is necessary to conclude the mechanisms by which red wine protects from CDH (Pearson, 1996).
Research has provided mixed results as to whether drinking red wine is more beneficial than drinking other forms of alcohol. For example, when 13 studies on the subject were combined, analysis showed that red wine offered a 10% higher risk reduction than other forms of alcohol. However, other studies and reviews of studies have failed to find any difference among alcoholic beverages. Some scientists suggest that lifestyle factors of diet, exercise, and SES may influence studies of this nature (Szmitko & Subodh, 2005). In addition, researchers have often found it difficult to conduct studies in this area because one person often consumes more than type of alcohol (Pearson, 1996).
In agreement with the websites, scientific sources such as the journal of the American Heart Association agree that although considerable amounts of data exits on this subject, the evidence is not sufficient enough to encourage patients who do not drink to start drinking in order to protect themselves from atherosclerosis. This is because, despite any suggestion of positive effects, studies have also found that alcohol consumption can also contribute to a number of medical problems such as high blood pressure, liver problems, cancer, pancreatitis, neurological disorders, and addiction. Therefore, the stance of the scientific community as based on reviews of research studies seems to be that moderate drinkers can continue drinking but increasing alcohol consumption in hopes of reducing the risk of CHD is not advised (Szmitko & Subodh, 2005).
What are some specific scientific studies researching these claims?
A number of prospective studies have been done on the relationship between drinking red wine and CHD. These studies address both if and how alcohol and specifically red wine work to reduce the risk of CHD. Overall, these studies support the idea that red wine does offer a protective affect against CHD; however, the results of studies researching how red wine does this are inconsistent and therefore further research is necessary.
One study attempted to research the type of alcohol and the drinking patterns associated with a reduced risk of CHD. Researchers administered surveys every four years for twelve years to assess individuals’ consumption of beer, red wine, white wine, and liquor and documented cases of fatal and nonfatal CHD over the twelve year period. The study found that men who drank alcohol three to seven days a week had reduced risk of myocardial infarction compared to those who drank alcohol less than once a week or consumed excessive amounts. This study also found that the type of beverage used had no affect on the benefits. (Mukamal et al., 2001)
Another study focused more specifically on how flavonoids affect the risk of CHD. Subjects were given a questionnaire to assess their intakes of flavonoids in the form of tea, vegetables, fruits, and red wine in 1986 and again in 1990. This study did not find a strong association between high levels of flavonoids in a person’s diet and decreased risk for heart disease. However, the data did support the idea that flavanoids may have a protective effect in individuals who already suffer from coronary heart disease (Rimm, Katan, Ascherio, Stampfer, & Willett, 1996). The results of this study indicate that theories that flavonoids are responsible for the protective effects of red wine require more research.
Another study examined the effects of resveratrol and red wine on the activity and aggregation of platelets in the blood. In this study, the platelets were isolated from men and hypercholesterolemic rabbits, and researchers induced platelet aggregation. When the samples were treated with resveratrol, researchers found that platelet activity was significantly inhibited both in vitro with both populations and in vivo with the rabbit subjects. Therefore, researchers concluded that red wine has some anti-clotting properties and speculated that this could be part of the reason red wine offers a protective effect against CHD (Wang et al., 2002).
Similarly, another study examined the effects of wine and grape juice on platelet activity. In the study, anesthetized dogs with constricted coronary arteries in which platelet activity and clotting had occurred were injected with various amounts of red wine, grape juice, and white wine. The study’s results indicated that certain compounds in grape juice and wine aided in the inhibition of platelet activity and the resultant decrease in blood clotting (Demrow, Slane, & Folts, 1995). This study once again supports the idea that compounds in red wine have anti-clotting properties.
Finally, a review of several recent studies on the effect of resveratrol found that resveratrols effects in the body are similar to the protective effects proposed for red wine in general. Therefore, researchers are continuing to look at how specifically resveratrol may give red wine some of its protective power. Hypothesis for these mechanisms emphasize how resveratrol may inhibit LDL oxidation and suppress platelet aggregation. All of these studies on the activity of resveratrol indicate that this could be a promising explanation for the risk-reducing effects of red wine, and therefore this idea merits further study (Wu et al., 2001).
Although a large number of observational studies support the protective effect of the moderate consumption of alcohol, no clinical trials have been performed to test the relationship between alcohol consumption and CHD. It is unlikely that randomized, controlled trials to investigate this issue and could ever be conducted, and it is clear that the results of research on how exactly red wine may lower the risk of CHD are inconsistent and inconclusive. Overall, red wine does seem to offer a protective effect against CHD, but the methods by which it does this are in need of further research. Therefore scientific journals emphasize that although red wine does seem to incur some benefits, these benefits stem only from drinking in moderation and individuals should consult a doctor about using red wine as a preventative matter particularly if they problematic medical histories.
Demrow, H., Slane, P., and Folts, J. (1995). Administration of wine and grape juice inhibits in vivo platelet activity and thrombosis in stenosed canine coronary arteries. Circulation, 91(4), 1182-1188.
Mukamal, K., Conigrave, K., Mittleman, M., Camargo, C., Stampfer, M., Walter, W., et al. (2003). Roles of drinking pattern and type of alcohol consumed in coronary heart disease in men. The New England Journal of Medicine, 348(2), 109-118.
Pearson, T. (1996). Alcohol and heart disease. Circulation, 94, 3023-3025.
Rimm, E., Katan, M., Ascherio, A., Stampfer, M., & Willett, W. (1996). Relation between intake of flavonoids and risk for coronary heart disease in male professionals. Annals of Internal Medicine, 125(5), 384 – 389.
Szmitko, P. and Subodh, V. (2005). Red wine and your heart. Circulation, 111, 10-11.
Wang, Z., Huang, Y., Zou, J., Cao, K., Xu, Y., & Wu, J. (2002). Effects of red wine and wine polyphenol resveratrol in platelet aggregation in vivo and in vitro. International Journal of Molecular Medicine, 9(1), 77-79.
Wu, J., Wang, Z., Hsieh, T., Bruder, J., Zou, J., & Huang, Y. (2001). Mechanism of cardioprotection by resveratrol, a phenolic antioxidant present in red wine. International Journal of Molecular Medicine, 8(1), 3-17.
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