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Alcohol's Effect On the Heart: A Summary of Recent Research Findings
Abundant research has been conducted recently on the subject of alcohol and its
protective role in heart disease. Most of the research focuses on exactly how much alcohol
consumption is considered protective, and the point at which its consumption becomes
harmful rather than beneficial. Another important question is whether some types of
alcohol, such as red wine, provide more benefit than others. Should people with heart
disease drink alcohol, and if so, how much? What about people who are at risk of
developing heart disease? We have summarized below various research findings on these
topics to help provide some answers to these questions. (See Summary
Overview and HeartInfo Editorial Comments
below.)
One recent study was led by researchers from Boston's Brigham and Women's Hospital and
Harvard Medical School and was conducted over a 10.7 year period. The study included over
22,000 men in the Physicians Health Study ranging in age from 40 to 84. Results of the
study, published in January in the Archives of Internal Medicine, revealed that
men who drink moderately (two to six alcoholic drinks per week) are healthier overall than
heavy drinkers (two or more drinks per day) and light drinkers (less than one drink per
week). Of the 1,206 deaths, 394 were from cardiovascular causes, 488 from cancer, and 324
from other causes. The researchers, led by Dr. Carlos A. Camargo Jr. found that compared
with light drinkers, the risk of dying from all causes was 28% lower in men who drank two
to four drinks per week, 21% lower in men who drank five or six drinks per week and 51%
higher for men who were considered heavy drinkers.
The decreased risk of death among moderate drinkers was mostly attributed to a 34% to 53%
reduction in the risk of dying from cardiovascular disease. Researchers also found that
heavy drinking caused no significant increase in heart disease deaths. However, heavy
drinkers faced a doubling of risk with respect to cancer death.
The researchers in this study noted that the subjects in the study who were heavy drinkers
seemed to share several qualities: they "tended to be older, smoke more, and be more
likely to have hypertension" than any other group. The researchers further noted that
since the study included men only, its findings are only applicable to men for the
following reason: it is difficult to make direct comparisons between the sexes given the
complication of factoring in the risk of breast cancer for women.
In another study conducted by the Northern Manhattan Stroke Study and reported by the
American Heart Association on February 7, 1997, researchers examined alcohol consumption
in the 12 months preceding a stroke in 423 patients and compared them to alcohol
consumption over a 12 month period for 793 people who did not have a stroke. They matched
the groups for age, race and sex and also adjusted the results for other stroke risk
factors.
In this study, researchers found that occasional drinkers (defined as drinking less than
one drink per month) had a 62% lower risk of stroke than non-drinkers. People who drank up
to two drinks a day reduced their stroke risk by 45% compared to non-drinkers. However,
consumption of more than five drinks a day tripled the risk of stroke. The researchers
also found that heavy drinkers who cut back their drinking habits enjoyed the same
benefits as lighter drinkers proving that changing habits can have an impact in reducing
stroke risk.
The American Heart Association (AHA) issued a science advisory in their December 1, 1996
issue of the journal Circulation advising that the health benefits of alcohol are
limited to one to two drinks a day. Dr. Thomas A. Pearson, head of AHA's nutrition
committee, further warns that heavy drinking can cause a variety of health problems
including high blood pressure and stroke, heart muscle disorders, many kinds of cancer,
liver and pancreas disease, along with accidents, homicide and suicide. He advises that
people whose medical and social problems are exacerbated by drinking should abstain
completely.
As an indication of the paradox of the alcohol debate, Dr. Pearson notes that
alcohol-related diseases account for 100,000 deaths in the U.S. annually. However, if
current drinkers stopped drinking, heart disease related deaths he estimates would
increase by 80,000 each year in the U.S.
There have been further debates regarding whether certain types of alcohol are better than
others. According to two studies reported by Reuters on March 22, 1996, the protective
effects of alcohol on coronary heart disease (CHD) are not contingent upon the kind of
alcohol consumed. Researchers believe that all types of alcohol reduce the risk of CHD at
least in part by reducing serum levels of LDL (bad) cholesterol. Alcohol raises the HDL
(good) cholesterol as well, which could play some role in protecting against heart
disease.
However, conflicting research has indicated that the antioxidants in red wine may be more
protective than other types of alcohol in preventing atherosclerosis. In a study conducted
in Sao Paulo, Brazil and presented at the 18th Congress of the European Society of
Cardiology in Birmingham, rabbits were fed a high cholesterol diet and either given red
wine, red wine without the alcohol, or no wine at all. After three months, the aorta (the
largest artery) was examined for fatty plaques . Researchers found that in the rabbits not
given any alcohol, 60% of their aortas were covered with fatty plaques; this declined to
50% in the rabbits fed the non-alcoholic red wine; and to 40% in the rabbits given red
wine. However, the researchers could not explain these results as all of the rabbits had
20 times the normal amounts of LDL (bad) cholesterol and total cholesterol in their blood
after eating the high fat diet. Their HDL (good) cholesterol levels were unaffected.
The researchers speculate that flavonoids, present both in fruits and vegetables and
red wine, "act as antioxidants and may prevent the oxidation of LDL cholesterol, a
step that facilitates plaque formation". Of course, this study did not compare red
wine to other forms of alcohol, so the question remains unanswered. Furthermore, all
animal studies must be interpreted with great caution regarding extrapolation to humans
and clinical recommendations. The concept that red wine has protective properties not
found in other types of alcohol is attractive but remains unproven. The data suggest, in
contrast, that all forms of alcohol are equally protective.
In summary, the issue of alcohol and heart disease is far from
settled. Nevertheless, some generalizations can be safely made: 1) drinking alcohol in
moderation (fewer than two drinks a day) may decrease risk of heart disease; 2) this
effect appears to be true for all types of alcohol and not limited to red wine; 3) if you
currently do not drink, it is not advisable that you start--alcohol should not be used as
a medication; 4) Discuss your drinking habits with your doctor.
HeartInfo Editorial Comment:
"Should I drink red wine (or other alcohol) for my heart?" Some form of this
question is asked of physicians very frequently, and is answered in many different ways.
Our favorite answer is: "Do you like to drink red wine (or other alcohol)?" If
the answer is yes and if you do not have medical and/or social problems that are
exacerbated by alcohol, a few drinks per week would seem a reasonable indulgence that may
happen to have a positive benefit. On the other hand, if the answer is no, it is not
advised that you begin drinking purely for medicinal value. There are too many other
proven ways to reduce risk of heart disease.
SOURCES:
American Heart Association Press Release February 7, 1997; American Medical Association's
Archives of Internal Medicine, January 13, 1997; Reuters January 13, 1997, Reuters
December 9, 1996; Circulation, December 1, 1996; Reuters August 30, 1996; Reuters
March 22, 1996.
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