Реферат: Does The Consumption Of Red Wine Lower
The Risk Of Heart Disease? Essay, Research Paper
Does the consumption of red wine lower the risk of heart disease?
The incidence of coronary heart disease (CHD) mortality in France is the lowest among industrial countries, despite the high incidence of several risk factors. In comparison to Americans, the French consume 3.8 times as much butter and 2.8 times as much lard, they have higher cholesterol and blood pressure levels, they smoke on a comparable level to Americans, and they don’t exercise quite as often. Despite these appalling health statistics, the French have a 2.5 fold less risk of dying as a result of heart disease. What can begin to explain this? This phenomenon, known as the “French Paradox,” was believed to be due to a vegetable and fruit rich Mediterranean diet. However, through various studies, researchers worldwide have come to agree that the French tradition of consuming red wine is at the root of explaining why the French enjoy a reduced risk of heart disease.
? So, does the consumption of red wine really reduce the risk of heart disease? There has been a consistent body of epidemiologic data that has alluded to the reduced incidence of mortality and morbidity from coronary heart disease (CHD) among those who consume alcohol in moderation in comparison with those who abstain. This protection has been attributed to the ethanol present in those beverages classified as “alcoholic.” But gaining further momentum is the evidence that polyphenols also display additional benefits, which at least in vitro and in cell culture experiments act as potent inhibitors of platelet aggregation and biological oxidation reactions associated with the generation of freed radicals. Polyphenols belong to the family of phytochemicals that are found in plants and contribute to a reduced risk of heart disease and cancer in people who consume them regularly.
Polyphenols are a relatively new phenomenon and have not conclusively made their case yet, but there is no disputing the reality that the advocacy of fruit and vegetables as essential components of a healthy diet is based upon their intrinsic content of theses same polyphenols. A major advantage of wine over fruit is that the dietary polyphenols are soluble and bioavailable in wine, which is the degree to which the amount of an ingested nutrient is absorbed and is available to the body. This is an advantage over solid vegetables and fruits, which contain their phenolic components in polymeric, insoluble or tightly bound, and compartmentalized forms that render them unavailable for absorption.
Since very little is known about the extent or amount of uptake of these dietary constituents, it remains to be fully established that red wine provides a more favorable medium than fruits and vegetables. While red wine is apparently a better source of polyphenols, it was necessary to check on wine’s inherent properties through other studies. The first study examines resveratrol, a polyphenol in red wine that has been associated with reduced heart disease. The second study examines whether alcohol-free red wine has the same effects as alcoholic red wine, so as to ascertain whether red wine intrinsically has preventive properties other alcoholic beverages, fruits, and vegetable may not have. And finally, the third study examines the effects of red wine, white wine, and grape juice on in vivo platelet activity and thrombosis in stenosed canine arteries.
The resveratrol study was a metabolic trial on cultured pulmonary artery endothelial cells to ascertain whether it, resveratrol, would induce nitric oxide synthase (NOS), a process that inhibits platelet growth, adhesion, and aggregation. Platelet activity is one of the many factors that go towards causing heart attacks.
The cultured heart cells were prepared and kept homogenous through fluorescent staining for diacylated low-density lipoprotein. They were then rountinely maintained with a fetal bovine serum that kept them viable. They were then harvested and counted by a hemocytometer (blood cell counter). Control cells were treated in the same way, except they were not treated with the resveratrol.
Because NOS produces a short-lived gas, these researchers tested the effects of resveratrol by assaying changes in ecNOS, an isoform of NOS specifically and expressed in endothelial cells. They found that resveratrol induced NOS and reduced endothelial cell proliferation, or platelet adhesion to the heart cells. As a result of this experiment, it is shown that the polyphenol resveratrol did alleviate platelet growth in the heart and effectively reduced the risk of clotting in the cultured heart cells.
ALCOHOL-FREE RED WINE
This Italian metabolic study endeavored to answer the question of whether it is the ethanol in wine or the polyphenols that are responsible for wine’s protective properties. To do this, these researchers used ten healthy non-smokers who did not use supplements or vitamins. These subjects asked to fast 12 hours prior to the trial. They were then given 113 mL of alcohol-free red wine. Blood samples were then taken at 30, 50, and 120 minutes after ingesting the wine. This process was then repeated one-week later using tap water and white wine.
To test their theory, the researchers studied whether the plasma antioxidant capacity increased and measured this as total radical-trapping antioxidant parameter (TRAP). This process would determine whether such an effect (TRAP) is associated with the presence of phenolic compounds in plasma. As they had predicted, the polyphenol content of the red wine was 20 times more active than it was in the white. So they expected to see significant results in the red wine trial. They found that the time trend of plasma TRAP levels after the ingestion of alcohol-free wine. TRAP values gradually rose in subjects who drank red wine, reaching its peak 50 minutes after ingestion and falling back to baseline after 2 hours. The TRAP did not change when the subjects drank water or the alcohol-free white wine. This study proves that not only the ethanol in red wine can protect against CHD, but that the concentration of polyphenols can also boost the protective properties of red wine. In essence, red wine has a dual protective ability against CHD, while fruit, vegetables, and other alcoholic beverages seem to have only one.
IN VIVO PLATELET ACTIVITY
This last metabolic study was conducted on mongrel dogs. Researchers here wished to reaffirm the protective capacity of ethanol in the platelet inhibition in atherosclerosis and CHD. 47 anesthetized dogs were prepared with an in vivo (Folts coronary thrombosis model) of mechanically stenosed coronary arteries and intimal damage. What this did was simulate the stenosed, or constricted, arteries of the heart as a result of atherosclerosis. Thombosis, or clotting of the hearts passages, would then be simulated through the stenosed coronary artery and cause cyclic flow reductions (CFRs) in coronary blood flow. These researchers wished to measure how the wine affected these detrimental CFRs.
15 dogs were then given an intravenous infusion of red wine diluted in saline (2mL of red wine per 200mL of saline). 7 dogs were given the same proportions of white wine, and 5 dogs were given grape juice. The CFRs in the red wine group were completely eliminated within 5 minutes. The CFRs were abolished for one hour. The grape juice had a similar effect, stopping the CFRs in 10 minutes, and the white wine had little to no affect.
Researchers here concluded that while ethanol possesses properties to inhibit platelet growth and disbursement, something more was to account of the properties of grape juice and red wine. They came to the conclusion that the polyphenols were most likely to account for this.
DOES RED WINE PREVENT HEART DISEASE?
The studies presented here clearly present metabolic proof that red wine does indeed have certain intrinsic properties that help to prevent heart disease. This proof certainly backs up previous epidemiological studies that also suggested an association between reduced heart disease risk and the moderate consumption of red wine. While it is clear that polyphenol may be the active agent in this protection, more study is needed to further ascertain other benefits.
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