Table of Contents
Introduction
Throughout the 10,000 or so years that humans have been drinking
fermented beverages, they’ve also been arguing about their merits and
demerits. The debate still simmers today, with a lively back-and-forth
over whether alcohol is good for you or bad for you.
It’s safe to say that alcohol is both a tonic and a poison. The
difference lies mostly in the dose. Moderate drinking seems to be good
for the heart and circulatory system, and probably protects against type
2 diabetes and gallstones. Heavy drinking is a major cause of
preventable death in most countries. In the U.S., alcohol is implicated
in about half of fatal traffic accidents. (
1)
Heavy drinking can damage the liver and heart, harm an unborn child,
increase the chances of developing breast and some other cancers,
contribute to depression and violence, and interfere with relationships.
Alcohol’s two-faced nature shouldn’t come as a surprise. The active
ingredient in alcoholic beverages, a simple molecule called ethanol,
affects the body in many different ways. It directly influences the
stomach, brain, heart, gallbladder, and liver. It affects levels of
lipids (cholesterol and triglycerides) and insulin in the blood, as well
as inflammation and coagulation. It also alters mood, concentration,
and coordination.
What’s Moderate Alcohol Intake? What’s a Drink?
Loose use of the terms “moderate” and “a drink” has fueled some of the ongoing debate about alcohol’s impact on health.

The comparatively low rate of heart disease in France despite a diet
that includes plenty of butter and cheese has become known as the French
paradox.
Some experts have suggested that red wine makes
the difference, but other research suggests that beverage choice appears
to have little effect on cardiovascular benefit.
In some studies, the term “moderate drinking” refers to less than one
drink per day, while in others it means three or four drinks per day.
Exactly what constitutes “a drink” is also fairly fluid. In fact, even
among alcohol researchers, there’s no universally accepted standard
drink definition. (
2)
In the U.S., one drink is usually considered to be 12 ounces of beer,
5 ounces of wine, or 1½ ounces of spirits (hard liquor such as gin or
whiskey). (
3) Each delivers about 12 to 14 grams of alcohol.
The definition of moderate drinking is something of a balancing act.
Moderate drinking sits at the point at which the health benefits of
alcohol clearly outweigh the risks.
The latest consensus places this point at no more than one to two
drinks per day for men, and no more than one drink per day for women.
This is the definition used by the U.S. Department of Agriculture and
the Dietary Guidelines for Americans, (
3) and is widely used in the United States.
Possible Health Benefits of Alcohol
What are some of the possible health benefits associated with moderate alcohol consumption?
Cardiovascular Disease
More than 100 prospective studies show an inverse association between
moderate drinking and risk of heart attack, ischemic (clot-caused)
stroke, peripheral vascular disease, sudden cardiac death, and death
from all cardiovascular causes. (
4) The effect is fairly consistent, corresponding to a 25 percent to 40 percent reduction in risk.
Learn more about the results of some large prospective
studies of alcohol consumption and cardiovascular disease.
The connection between moderate drinking and lower risk of
cardiovascular disease has been observed in men and women. It applies to
people who do not apparently have heart disease, and also to those at
high risk for having a heart attack or stroke or dying of cardiovascular
disease, including those with type 2 diabetes, (
5,
6) high blood pressure, (
7,
8) and existing cardiovascular disease. (
7,
8) The benefits also extend to older individuals. (
9)
The idea that moderate drinking protects against cardiovascular
disease makes sense biologically and scientifically. Moderate amounts of
alcohol raise levels of high-density lipoprotein (HDL, or “good”
cholesterol), (
10)
and higher HDL levels are associated with greater protection against
heart disease. Moderate alcohol consumption has also been linked with
beneficial changes ranging from better sensitivity to insulin to
improvements in factors that influence blood clotting, such as tissue
type plasminogen activator, fibrinogen, clotting factor VII, and von
Willebrand factor. (
10)
Such changes would tend to prevent the formation of small blood clots
that can block arteries in the heart, neck, and brain, the ultimate
cause of many heart attacks and the most common kind of stroke.
Does Alcohol Cause These Benefits?
People who drink in moderation are different from non-drinkers or
heavy drinkers in ways that could influence health and disease.
Folate, the B vitamin that helps guide the
development of an embryo’s spinal cord, has equally important jobs later
in life. One of the biggest is helping to build DNA, the molecule that
carries the code of life. In this way, folate is essential for accurate
cell division.
Alcohol blocks the absorption of folate and
inactivates folate in the blood and tissues. It’s possible that this
interaction may be how alcohol consumption increases the risk of breast,
colon, and other cancers.
Getting extra folate may cancel out this
alcohol-related increase. In the Nurses’ Health Study, for example,
among women who consumed one alcoholic drink a day or more, those who
had the highest levels of this B vitamin in their blood were 90% less
likely to develop breast cancer than those who had the lowest levels of
the B vitamin. (
28)
An earlier study suggested that getting 600 micrograms a day of folate
could counteract the effect of moderate alcohol consumption on breast
cancer risk. (
26)
Part of a national 1985 health interview survey showed that moderate
drinkers were more likely than non-drinkers or heavy drinkers to be at a
healthy weight, to get seven to eight hours of sleep a night, and to
exercise regularly. (
11)
Researchers have statistically accounted for such confounders, and they
do not come close to accounting for the relationship between alcohol
and heart disease. This, plus the clearly beneficial effects of alcohol
on cardiovascular risk factors, makes a compelling case that alcohol
itself, when used in moderation, reduces the risk of cardiovascular
disease.
The most definitive way to investigate the effect of alcohol on
cardiovascular disease would be with a large trial in which some
volunteers were randomly assigned to have one or more alcoholic drinks a
day and others had drinks that looked, tasted, and smelled like alcohol
but were actually alcohol free. Many of these trials have been
conducted for weeks, and in a few cases months, to look at changes in
the blood, but a long-term trial to test experimentally the effects of
alcohol on cardiovascular disease over many years will probably never be
done. Nevertheless, the connection between moderate drinking and
cardiovascular disease almost certainly represents a cause-and-effect
relationship.
Beyond the Heart
The benefits of moderate drinking aren’t limited to the heart. In the
Nurses’ Health Study, the Health Professionals Follow-up Study, and
other studies, gallstones (
12,
13) and type 2 diabetes (
5,
14,
15)
were less likely to occur in moderate drinkers than in non-drinkers.
The emphasis here, as elsewhere, is on moderate drinking. In a
meta-analysis of 15 original prospective cohort studies that followed
369,862 participants for an average of 12 years, no benefit was observed
for heavy drinkers who consumed more than 48 grams of alcohol (the
equivalent of four drinks) a day. (
5)
The social and psychological benefits of alcohol can’t be ignored. A
drink before a meal can improve digestion or offer a soothing respite at
the end of a stressful day; the occasional drink with friends can be a
social tonic. These physical and psychic effects may contribute to
health and well-being.
Drinking Patterns Matter
What you drink (beer or wine) doesn’t seem to be nearly as important
as how you drink. Having seven drinks on a Saturday night and then not
drinking the rest of the week isn’t at all the equivalent of having one
drink a day. The weekly total may be the same, but the health
implications aren’t. Among participants in the Health Professionals
Follow-up Study, consumption of alcohol on at least three or four days a
week was inversely associated with the risk for myocardial infarction.
The amount consumed, under 10 grams a day or more than 30 grams, didn’t
seem to matter as much as the regularity of consumption. (
16) A similar pattern was seen in Danish men. (
17)
The Dark Side of Alcohol

If all drinkers limited themselves to a single drink a day, we probably
wouldn’t need as many cardiologists, liver specialists, mental health
professionals, and substance abuse counselors. But not everyone who
likes to drink alcohol stops at just one. While most people drink in
moderation, some don’t.
On the personal level, heavy drinking can take a toll on the body. It
can cause inflammation of the liver (alcoholic hepatitis) and lead to
scarring of the liver (cirrhosis), a potentially fatal disease. Heavy
drinking can increase blood pressure and damage heart muscle
(cardiomyopathy). It has also been linked with several cancers: The
World Cancer Research Fund and American Institute for Cancer Research
indicate that there is convincing evidence linking alcohol use to cancer
of the mouth, pharynx, larynx, esophagus, breast, and colon and rectum
in men, and probable evidence that its use contributes to liver cancer
and colorectal cancer in women. (
18) The risk is multiplied for drinkers who also smoke tobacco.
Problem drinking also touches drinkers’ families, friends, and
communities. According to the National Institute on Alcohol Abuse and
Alcoholism and others:
- 18.2 million Americans meet standard criteria for alcohol abuse or alcoholism. (19)
- Alcohol plays a role in one in three cases of violent crime. (20)
- More than 16,000 people die each year in automobile accidents in which alcohol is involved. (21)
- Alcohol abuse costs more than $185 billion dollars a year. (22)
Even moderate drinking carries some risks. Alcohol can disrupt sleep.
Its ability to cloud judgment is legendary. Alcohol interacts in
potentially dangerous ways with a variety of medications, including
acetaminophen, antidepressants, anticonvulsants, painkillers, and
sedatives. It is also addictive, especially for people with a family
history of alcoholism.
Alcohol Increases Risk of Developing Breast Cancer
There is convincing evidence that alcohol consumption increases the risk of breast cancer. (
23,
24)
In a combined analysis of six large prospective studies involving more
than 320,000 women, researchers found that having two or more drinks a
day increased the chances of developing breast cancer as much as 41
percent. (
23)
This doesn’t mean that 40 percent or so of women who have two drinks a
day will get breast cancer. Instead, it is the difference between about
12.7 of every 100 women developing breast cancer during their
lifetime—the current average risk in the US—and 17 to 18 of every 100
women developing the disease. This modest increase would translate to
significantly more women with breast cancer each year.
Adequate daily intake of folate, at least 600 micrograms a day, appears to mitigate this increased risk. (
25,
26) (Read more about
folate and alcohol.)
Genes Play a Role
Twin, family, and adoption studies have firmly established that
genetics plays an important role in determining an individual’s
preferences for alcohol and his or her likelihood for developing
alcoholism. Alcoholism doesn’t follow the simple rules of inheritance
set out by Gregor Mendel. Instead, it is influenced by several genes
that interact with each other and with environmental factors. (
1)
There is also some evidence that genes influence how alcohol affects
the cardiovascular system. An enzyme called alcohol dehydrogenase helps
metabolize alcohol. One variant of this enzyme, called alcohol
dehydrogenase type 1C (ADH1C), comes in two “flavors.” One quickly
breaks down alcohol, the other does it more slowly. Moderate drinkers
who have two copies of the gene for the slow-acting enzyme are at much
lower risk for cardiovascular disease than moderate drinkers who have
two genes for the fast-acting enzyme. (
27) Those with one gene for the slow-acting enzyme and one for the faster enzyme fall in between.
It’s possible that the fast-acting enzyme breaks down alcohol before
it can have a beneficial effect on HDL and clotting factors.
Interestingly, these differences in the ADH1C gene do not influence the
risk of heart disease among people who don’t drink alcohol. This adds
strong indirect evidence that alcohol itself reduces heart disease risk.
Shifting Benefits and Risks
The benefits and risks of moderate drinking change over a lifetime.
In general, risks exceed benefits until middle age, when cardiovascular
disease begins to account for an increasingly large share of the burden
of disease and death.
- For a pregnant woman and her unborn child, a recovering alcoholic, a
person with liver disease, and people taking one or more medications
that interact with alcohol, moderate drinking offers little benefit and
substantial risks.
- For a 30-year-old man, the increased risk of alcohol-related
accidents outweighs the possible heart-related benefits of moderate
alcohol consumption.
- For a 60-year-old man, a drink a day may offer protection against
heart disease that is likely to outweigh potential harm (assuming he
isn’t prone to alcoholism).
- For a 60-year-old woman, the benefit/risk calculations are trickier.
Ten times more women die each year from heart disease (460,000) than
from breast cancer (41,000). However, studies show that women are far
more afraid of developing breast cancer than heart disease, something
that must be factored into the equation.
The Bottom Line: Balancing Risks and Benefits
Given the complexity of alcohol’s effects on the body and the
complexity of the people who drink it, blanket recommendations about
alcohol are out of the question. Because each of us has unique personal
and family histories, alcohol offers each person a different spectrum of
benefits and risks. Whether or not to drink alcohol, especially for
“medicinal purposes,” requires careful balancing of these benefits and
risks.
Your health-care provider should be able to help you do this. Your
overall health and risks for alcohol-associated conditions should factor
into the equation. If you are thin, physically active, don’t smoke, eat
a healthy diet, and have no family history of heart disease, drinking
alcohol won’t add much to decreasing your risk of cardiovascular
disease.
If you don’t drink, there’s no need to start. You can get similar
benefits with exercise (beginning to exercise if you don’t already or
boosting the intensity and duration of your activity) or healthier
eating. If you are a man with no history of alcoholism who is at
moderate to high risk for heart disease, a daily alcoholic drink could
reduce that risk. Moderate drinking might be especially beneficial if
you have low HDL that just won’t budge upward with diet and exercise.
If you are a woman with no history of alcoholism who is at moderate
to high risk for heart disease, the possible benefits of a daily drink
must be balanced against the small increase in risk of breast cancer.
If you already drink alcohol or plan to begin, keep it moderate—no
more than two drinks a day for men or one drink a day for women. And
make sure you get plenty of folate, at least 600 micrograms a day.
References
1.10th Special Report to the U.S. Congress on Alcohol and Health.
National Institute on Alcohol Abuse and Alcoholism.
2.Kloner RA, Rezkalla SH. To drink or not to drink? That is the question.
Circulation. 2007; 116:1306–17.
3.Dietary guidelines for Americans 2005.
U.S. Department of Agriculture.
4.Goldberg IJ, Mosca L, Piano MR, Fisher
EA. AHA Science Advisory: Wine and your heart: a science advisory for
healthcare professionals from the Nutrition Committee, Council on
Epidemiology and Prevention, and Council on Cardiovascular Nursing of
the American Heart Association.
Circulation. 2001; 103:472–5.
5.Koppes LL, Dekker JM, Hendriks HF, Bouter
LM, Heine RJ. Moderate alcohol consumption lowers the risk of type 2
diabetes: a meta–analysis of prospective observational studies.
Diabetes Care. 2005; 28:719–25.
6. Solomon CG, Hu FB, Stampfer MJ, et al.
Moderate alcohol consumption and risk of coronary heart disease among
women with type 2 diabetes mellitus.
Circulation. 2000; 102:494–99.
7.Mukamal KJ, Maclure M, Muller JE,
Sherwood JB, Mittleman MA. Prior alcohol consumption and mortality
following acute myocardial infarction.
JAMA. 2001; 285:1965–70.
8.Muntwyler J, Hennekens CH, Buring JE,
Gaziano JM. Mortality and light to moderate alcohol consumption after
myocardial infarction.
Lancet. 1998; 352:1882–85.
9.Mukamal KJ, Chung H, Jenny NS, et al.
Alcohol consumption and risk of coronary heart disease in older adults:
the Cardiovascular Health Study.
J Am Geriatr Soc. 2006; 54:30–7.
10.Booyse FM, Pan W, Grenett HE, et al. Mechanism by which alcohol and wine polyphenols affect coronary heart disease risk.
Ann Epidemiol. 2007; 17:S24–31.
11.Camargo CA, Jr., Stampfer MJ, Glynn
RJ, et al. Prospective study of moderate alcohol consumption and risk of
peripheral arterial disease in US male physicians.
Circulation. 1997; 95:577–80.
12.Grodstein F, Colditz GA, Hunter DJ,
Manson JE, Willett WC, Stampfer MJ. A prospective study of symptomatic
gallstones in women: relation with oral contraceptives and other risk
factors.
Obstet Gynecol. 1994; 84:207–14.
13.Leitzmann MF, Giovannucci EL, Stampfer
MJ, et al. Prospective study of alcohol consumption patterns in
relation to symptomatic gallstone disease in men.
Alcohol Clin Exp Res. 1999; 23:835–41.
14.Conigrave KM, Hu BF, Camargo CA, Jr.,
Stampfer MJ, Willett WC, Rimm EB. A prospective study of drinking
patterns in relation to risk of type 2 diabetes among men.
Diabetes. 2001; 50:2390–95.
15.Djousse L, Biggs ML, Mukamal KJ,
Siscovick DS. Alcohol consumption and type 2 diabetes among older
adults: the Cardiovascular Health Study.
Obesity. (Silver Spring) 2007; 15:1758–65.
16.Mukamal KJ, Conigrave KM, Mittleman
MA, et al. Roles of drinking pattern and type of alcohol consumed in
coronary heart disease in men.
N Engl J Med. 2003; 348:109–18.
17.Tolstrup J, Jensen MK, Tjonneland A,
Overvad K, Mukamal KJ, Gronbaek M. Prospective study of alcohol drinking
patterns and coronary heart disease in women and men.
BMJ. 2006; 332:1244–48.
18.World Cancer Research Fund,
American Institute for Cancer Research. Food, Nutrition, Physical Activity, and the Prevention of Cancer: A Global Perspective. Washington, D.C.: AICR, 2007.
19.The NSDUH Report. Alcohol Dependence or Abuse—2002, 2003, & 2004.
U.S. Substance Abuse and Mental Health Services Administration.
20.Crime characteristics, 2006. U.S.
Department of Justice.
21.Impaired driving.
Centers for Disease Control and Prevention.
22.Updating Estimates of the Economic Costs of Alcohol Abuse in the United States. National Institute on Drug Abuse,
National Institute on Alcohol Abuse and Alcoholism.
23.Smith–Warner SA, Spiegelman D, Yaun SS, et al. Alcohol and breast cancer in women: a pooled analysis of cohort studies.
JAMA. 1998; 279:535–40.
24.Hamajima N, Hirose K, Tajima K, et al.
Alcohol, tobacco, and breast cancer—collaborative reanalysis of
individual data from 53 epidemiological studies, including 58,515 women
with breast cancer and 95,067 women without the disease.
Br J Cancer. 2002; 87:1234–45.
25.Baglietto L, English DR, Gertig DM,
Hopper JL, Giles GG. Does dietary folate intake modify effect of alcohol
consumption on breast cancer risk? Prospective cohort study.
BMJ. 2005; 331:807.
26.Zhang S, Hunter DJ, Hankinson SE, et al. A prospective study of folate intake and the risk of breast cancer.
JAMA. 1999; 281:1632–37.
27.Hines LM, Stampfer MJ, Ma J, et al.
Genetic variation in alcohol dehydrogenase and the beneficial effect of
moderate alcohol consumption on myocardial infarction.
N Engl J Med. 2001; 344:549–55.
28.Zhang SM, Willett WC, Selhub J, et al. Plasma folate, vitamin B6, vitamin B12, homocysteine, and risk of breast cancer.
J Natl Cancer Inst. 2003; 95:373–80.