Alcohol And The Heart-Part I
Part I of II
Alcoholism is one of the more common factors identified with cardiomyopathy. It is estimated that two-thirds of the adult population in the United States uses alcohol making it one of the most widely used addictive drugs. It is also a unique substance in that a small amount may have some benefit on cardiovascular morbidity and mortality; yet as consumption increases, it can have negative and even devastating effects on the body. The toxic effect of alcohol extends to the brain, the liver, the heart, and many other organs.
About two-thirds of the adult population report drinking alcohol and ten percent of them are heavy drinkers. Men drink more than women yet women are more sensitive to the effects of alcohol. Even though women in one study drank only sixty percent of the lifetime alcohol compared to men, they had a higher incidence of heart disease due to alcohol (1). Alcohol consumption is also more prevalent among adolescents with rates ranging from ten to thirty-five percent. It is more prevalent among young men than young women; among whites students than black students with white male adolescents having the highest rate of drinking.
Alcohol from a metabolic standpoint is absorbed in the stomach and small intestine. It is then distributed to tissues that are rich in water content and blood flow which is why the brain, heart and liver are prime targets for its effects (2).
Most American adults consider themselves moderate drinkers. Many authorities consider moderate alcohol consumption to be defined by daily indigestion of twelve to twenty-four grams of alcohol such as beer which is two twelve ounce containers, unfortified wine - two four ounce glasses or spirits which is .7 to 1.4 ounces of 86 proof whiskey or similar spirits. Those are only average values. Consideration must be given to factors such as lower or higher than average body weight and sex. In the national health interview surveys done in 1992, most American men and women reported consuming alcohol during the prior year. Approximately 7.4 percent or 14 million U.S. adults met standard diagnostic criteria for alcohol abuse or alcohol dependence according to this survey. Alcohol consumption is in direct relation to total mortality rate. The lowest mortality occurs in those who consume one or two drinks per day. Total mortality rises rapidly with increasing number of drinks of more than two per day. Some studies have shown a consistent thirty to fifty percent reduction in relative risks for coronary heart disease among moderate drinkers (4). One large study showed that both cardiovascular and overall mortality rates decline as the number of drinks increase to two per day. Above two drinks, however, not only was there no further decrease in cardiovascular mortality, but overall mortality increased with each additional daily drink consumed. The deaths can be attributed to liver disease, injuries, or alcohol related cancers (especially breast cancer in women). Other risks of excessive alcohol use include hypertension, stroke, alcoholism and cardiomyopathy.
It is interesting that the cardio protective effect of alcohol extends to patients who do not follow heart healthy practices in many other ways. The co-existence of the heart unhealthy diet and the relatively low risks for coronary heart in France has been called the French paradox (5). Some investigators have proposed that the inclusion of moderate wine consumption as part of daily life is the basis of the paradox. Others believe that the paradox does not exist and represents a misinterpretation of data.
What, may we ask, is cardio protective about alcoholic beverages? Some studies have attempted to identify distinctive components of one type of alcoholic beverage that might give it the cardio protective advantage over others. Special claims have been made for red wine in particular because of its flavanoids and other compounds. These compounds are anti-oxidants that inhibit liquid per-oxidation which is believed to convert normal LDL into a more atherogenic particle. Both the clinical and research studies of the effects of red wine and purple grape juice show improved endothelial function and reduced susceptibility of LDL to oxidation (6). The results of the claim that some components of wood aged products, such as red wine, cognac and whiskey block the synthesis of pro-inflammatory components that induce vascular relaxation by mechanisms dependent or independent of nitrous oxide. There are also clinical studies that show little or no difference among beverage types. It would appear, based on a live study of clinical and basic research data over many decades, that the major cardio protective ingredient in beer, wine and sprits is the same; namely alcohol. Therefore, when one looks for the mechanism by which beer, wine or spirits provide cardio protection, one should look at the effects of risk factors and metabolic pathways that are effected by alcohol.
Dr. Henry Pownall in a recent article described a number of diverse conditions in which alcohol is cardio protective.
First is thrombotic disease.
There is some evidence according to Dr. Pownalll, that alcohol is anti thrombotic. Alcohol consumption inhibits platelet aggregation, reduces the production of thromboxane(7), which is a stimulant of auto-aggregation of platelets. Alcohol may also inhibit blood coagulation and thrombosis by mechanisms other than reduced platelet aggregation time. One study reviewed by Dr. Pownall found a J curved relationship between alcohol consumption and plasma fibrinogen concentration. It is likely, therefore, that fibrinogen is simply not a marker for the inflammation associated with atherothrombosis but is part of the cause of the chain of events leading to the disease.
Second is Weight Control
Alcohol accounts for about 6% of total calories in the average U.S. diet. This is significant. When one considers the cumulative effect of daily alcohol consumption, 3,000 calories are added to the diet in a month which corresponds to a weight gain of about one pound. Alcohol consumption also tends to co-exist with heart unhealthy practices such as smoking and overeating. Therefore, abstinence or restricted alcohol consumption is likely to contribute to a more heart healthy lifestyle.
Third is hypertension.
It is now generally agreed that heavy drinking can cause high blood pressure and a cessation of excessive drinking can help normalize blood pressure. In addition, the consumption of excess alcohol makes the treatment of hypertension more difficult. The effect of moderate drinking on blood pressure is not as clear. One thing that has been demonstrated is that there was no effect on blood pressure by reducing alcohol intake by one-half.
Fourth is Stroke
Stroke is the leading cause of death in the United States following coronary heart disease and all cancers. Many of the physiological effects of alcohol may modify the risks of stroke including the increases in blood pressures and HDL.
Alcohol consumption has distinct relations with ischemic and hemmorhagic strokes. Rates of ischemic strokes appear to be decreased in both men and women who consume light to moderate amounts of alcohol(8). The increase in HDL, decrease in Lp(a) and reduced platelet aggregation ,are among suggested mechanisms for their benefit. This benefit appears to be limited to Caucasians, is not present in Asian populations or in African-Americans. The Northern Manhattan Stroke Study, however, did find the protective effects both in Caucasians, African-Americans and Hispanics.
According to recent data from the Physicians Health Study conducted in men, reductions in risk for total stroke and for ischemic stroke(8) occur with as little as one drink a week with no increased benefit from greater consumption up to one drink per day. Conversely, heavy drinking is well known to increase risks for both ischemic and hemmorhagic strokes. Likewise, data published in 1999 from a Finish population suggests that the dose response relation between alcohol consumption and stroke risks varies by stroke sub-type.
In terms of alcohol and atherosclerosis, personal and family medical history must be evaluated. Much has been learned over the last three decades about the identity and management of risk factors for cardiovascular disease. Many of the early studies showed a strong association between the incidence of myocardial infarction and elevations of total cholesterol. These findings led to the LRC-CPPT trial using cholestyramine as an intervention to reduce rates of first coronary events through a reduction in total cholesterol. Subsequent studies focused on the strong association between elevated LDL and atherosclerotic disease. Clinically the use of statins which are inhibitors in cholesterol biosynthesis have been shown to increase the number of LDL receptors.
The S-4 Study (Scandinavian Simvastatian Survival Study),the Cholesterol and Recurrent Events CARE) and the Woscops Long Term Intervention with Pravachol have shown that statins reduce coronary heart disease incidents in patients with and without coronary disease as well as all cause mortality heart disease in patients. In spite of the success of the statin therapy, atherosclerotic disease remains a major health problem as many non LDL factors exist. Among them, type II diabetes mellitus, low HDL, high triglyceride, and the occurrence of small dense LDL, that exhibits impaired binding to LDL receptors in some cells. These risk factors are strongly inter-related and occur as a cluster in subjects who have Insulin Resistance Syndrome (IRS)_ also known as metabolic syndrome X. IRS syndrome is also associated with hypertension, hyperinsulinism anemia, hyperglycemia and evaluations of plasma non esterified fatty acids
In Part II we will examine the metabolic effects of Alcohol as well as its cardioprotective nature.
Footnotes:
1) Marquez’ The greater risk of Alcoholic Cardiomyopathy JACC 1995;274:149-154
2) Golldstein,D,The Pharmacology of Alcohol 1983
3) Moushmoush,The long term effects of Alcohol on the CardioVascular System Arch.Int.Med. 1991;151:36-42
4) Pownall,H.J.,Alcohol and Coronary Heart Disease:2000
5) Gaziano,Moderate Alcohol Intake and Decreased Risk of Myocardial Infarction NEJM;1993:329:1829-1834
6) Friedman,LA, Heart Disease Mortality and Alcohol Consumption in Framingham AM>J>EPID>,1986;124:481-486
7) Hommel,M., Alcohol for Stroke prevention NEJM.,1999;341:1829-1834
Sacc0The Protective Effect of Moderate Alcohol consumption on ischemic stroke JAMA 1999;281:53-60
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