Patient education: Risks and benefits of alcohol (Beyond the Basics)
- Kenneth J Mukamal, MD
Kenneth J Mukamal, MD
- Associate Professor of Medicine
- Harvard Medical School
Is alcohol good for your health?
For many reasons, this is a question without simple or clear-cut answers. Drinking too much alcohol contributes to accidents and injuries and can lead to liver disease, high blood pressure, various cancers, and birth defects, among other health problems. However, moderate alcohol use may provide certain health benefits, particularly with regard to coronary heart disease. Understanding the possible risks and benefits of alcohol is essential to make an informed decision about alcohol use.
Alcohol abuse is discussed separately. (See "Patient education: Alcohol use — when is drinking a problem? (Beyond the Basics)".)
HOW MUCH IS ONE DRINK?
Alcoholic drinks come in multiple forms and contain differing amounts of pure alcohol (ethanol). In the United States, one portion of alcohol is defined as approximately 10 to 15 grams of ethanol, which can be found in:
●One 12 ounce bottle or can of beer (roughly equivalent to the 330 mL cans of beers sold in some countries)
●One 5 ounce serving of wine (about 150 mL)
●One shot (1.5 ounces) of 80-proof distilled spirits (about 50 mL)
Moderate drinking is generally defined as 3 to 9 servings of alcohol per week, depending on age, sex, and other conditions. For example, the National Institute on Alcohol Abuse and Alcoholism defines ‘low-risk’ drinking as no more than three drinks on any single day and no more than seven drinks per week for women, and no more than four drinks on any single day and no more than 14 drinks per week for a man.
Internationally, there is a broad range of what defines a “standard drink,” ranging from 8 grams in the United Kingdom to 19.75 grams in Japan .
HEALTH CONDITIONS AND ALCOHOL
Multiple studies suggest that consuming alcohol can affect the risk of developing certain health conditions.
Cardiovascular disease — Cardiovascular disease, including disorders of the heart, blood vessels, and blood circulation, is the leading cause of death in the United States. However, several studies suggest that moderate alcohol use, as compared to heavy drinking or abstaining, decreases the risk of coronary heart disease (CHD).
High blood pressure — People who consume more than two drinks per day have up to a twofold increase in the incidence of high blood pressure compared with nondrinkers. However, the effect of drinking less than two drinks per day on high blood pressure remains unclear. (See "Patient education: High blood pressure in adults (Beyond the Basics)".)
Heart attack — Drinking a moderate amount of alcohol is associated with lower risk of having a heart attack. (See "Patient education: Heart attack recovery (Beyond the Basics)".)
Atrial fibrillation — Drinking several drinks at a single occasion, even among individuals who otherwise drink safely, can induce abnormal heart rhythms, including atrial fibrillation. There may be a slightly increased risk of atrial fibrillation (the most common chronic heart rhythm disturbance) among moderate drinkers, although it is still uncertain if this may result from occasional binges among otherwise moderate drinkers or occurs even within recommended limits of alcohol use. (See "Patient education: Atrial fibrillation (Beyond the Basics)".)
Peripheral vascular disease — Peripheral vascular disease can cause pain in the calves with walking, also known as claudication. Moderate alcohol use reduces the risk of peripheral artery disease in healthy men. (See "Patient education: Peripheral artery disease and claudication (Beyond the Basics)".)
Stroke — Alcohol consumption has been shown to affect the risk of stroke in contradictory ways, depending upon the amount of alcohol consumed and the type of stroke. A stroke occurs when brain tissue dies as a result of a sudden, severe disruption of blood flow and insufficient oxygen. Strokes may be due to a blockage (ischemic stroke) or rupture and leakage (hemorrhagic stroke) of one of the blood vessels supplying the brain.
Heavy alcohol use increases the risk of both ischemic and hemorrhagic stroke. Moderate alcohol use is associated with fewer ischemic strokes; the risk appears to be lowest in people who consume one drink or less per day. In contrast, the risk of hemorrhagic stroke appears to rise even with minimal alcohol use.
Breast cancer — There is consistent evidence that breast cancer risk is higher for women consuming moderate to high levels of alcohol (three or more drinks/day) compared with abstainers. Drinking as little as one to two drinks per day also appears to increase this risk. (See "Patient education: Factors that modify breast cancer risk in women (Beyond the Basics)".)
Taking folic acid (folate) may reduce the effect of alcohol consumption on breast cancer, suggesting that women who drink alcohol may benefit from a daily multivitamin fortified with folic acid.
Cancers of the head and neck and digestive tract — Alcohol use has been linked to several types of cancer of the head and neck and digestive (gastrointestinal) tract, even at low levels of consumption. People who drink and smoke have a greater risk than would be expected from either factor alone.
Cancer arising within liver cells (hepatocellular carcinoma) has been linked to alcohol use. This may be related to liver scarring (ie, cirrhosis) that occurs in people who consume excessive amounts of alcohol since cirrhosis is a major cause of hepatocellular carcinoma. Low levels of alcohol do not clearly cause cirrhosis. (See "Patient education: Cirrhosis (Beyond the Basics)".)
However, even at low levels, drinking may increase the risk of hepatocellular cancer in people with inflammation of the liver (hepatitis) due to infection with certain viruses (ie, hepatitis C virus). People with chronic hepatitis should avoid alcohol. (See "Patient education: Hepatitis C (Beyond the Basics)".)
Cirrhosis — Low levels of alcohol do not clearly cause cirrhosis. Heavy drinking is generally required to cause cirrhosis in men in the absence of other factors.
Gallstones — Moderate alcohol use has been shown to lower the risk of gallstones. However, heavy drinking may reverse this benefit. (See "Patient education: Gallstones (Beyond the Basics)".)
Pancreatitis — Heavy drinking increases the risk of both sudden (acute) and long-term (chronic) inflammation of the pancreas (pancreatitis). (See "Patient education: Acute pancreatitis (Beyond the Basics)" and "Patient education: Chronic pancreatitis (Beyond the Basics)".)
Osteoporosis — Heavy drinking increases the risk of hip fractures because it increases the risk of both osteoporosis and falls.
Pregnancy — There is a significant risk of birth defects related to use of alcohol use during pregnancy. Heavy drinking can cause fetal alcohol syndrome, which prevents normal growth, and may cause intellectual disability (mental retardation), malformations of the skull and face, and other findings.
Moderate alcohol consumption may also be harmful, although this is a matter of some controversy. There is no known benefit of alcohol use during pregnancy. Thus, experts advise completely avoiding alcohol during pregnancy.
Perception of health and quality of life — Excessive and frequent alcohol use reduces quality of life for individuals, their families, and others around them, potentially leading to failure at work or school, interpersonal problems, and physically hazardous situations.
Accidents and trauma — Alcohol use increases the risks and severity of injury from motor vehicle accidents.
Exposure to alcohol is generally measured in blood alcohol concentration (BAC) rather than drinks per day or week. In most of the United States, the legal BAC limit for driving is 0.08 percent, which corresponds to about 4 drinks for a 200 pound man and 2.5 drinks for a 150 pound woman. However, the risk of having an accident while driving doubles at a BAC of only 0.05 percent, and driving ability is impaired with BACs as low as 0.02 percent.
Alcohol also increases the risk of injury from other sources. It has been shown to impair a pilot's ability to fly and an operator's ability to control a boat, bicycle, and snowmobile. In addition, occupational injuries, falls, drownings, burns, and hypothermia are more common in those who use alcohol, particularly in heavy drinkers.
Violence — Alcohol is involved in more than one-quarter of all rapes, at least one-half of serious assaults, and one-half to two-thirds of all homicides.
Suicide — Alcohol abuse is associated with an increased risk of suicide. Although moderate drinking does not appear to raise suicide risk, episodes of heavy drinking cause disinhibition that can increase suicide risk.
IS ALCOHOL SAFE FOR ME?
The bottom line is that it is difficult to weigh the benefits and risks of alcohol. Nevertheless, several important conclusions can be drawn:
●Beginning to drink alcohol may be inappropriate for people who have been lifelong abstainers. There is no evidence that lifelong abstainers who begin drinking in middle or older age will lower their risk of any disease.
●The diseases that may be prevented by moderate drinking (eg, coronary heart disease and ischemic stroke) are most prevalent in older adults, men, and people with CHD risk factors (eg, hypertension, hypercholesterolemia, smoking, diabetes mellitus). For these groups, moderate alcohol use may reduce their risk of these conditions.
●For young to middle-aged adults, particularly women, moderate alcohol use increases the risk of the most common causes of death, such as breast cancer and trauma. Men under age 45 years also may experience more harm than benefit from drinking. In these younger age groups, moderate alcohol use is unlikely to reduce the risk of dying.
Consuming less than one drink daily appears to be safe (that is, if not done before or while operating a car or heavy equipment), although even that level of drinking can be dangerous for some people (see next section).
Reasons to avoid alcohol — Alcohol use is not recommended for individuals who:
●Are younger than the legal drinking age (21 years in most states within the United States)
●Have a personal or strong family history of alcoholism
●Have liver or pancreatic disease related to alcohol
●Have precancerous conditions of the digestive tract
●Operate potentially dangerous equipment or machinery (including cars, boats, planes, or construction equipment)
Wine versus other alcoholic beverages — Some research suggests that wine provides the strongest protection against cardiovascular disease, possibly due to naturally occurring compounds known as flavonoids. In France, for example, death from CHD is lower than would be expected from the high rate of smoking and saturated fats in the diet; this "French paradox" has been attributed to frequent red wine consumption.
However, other studies indicate that all alcoholic beverages offer cardioprotective benefits. Whether beverage type matters for specific diseases other than CHD remains uncertain, although most evidence suggests that it does not.
A safe dose of alcohol — As mentioned above, for some people, no amount of alcohol is considered safe. (See 'Reasons to avoid alcohol' above.) However, for individuals without such conditions, the healthiest dose of alcohol appears to be in the range of 0.5 to 1 drink of alcohol daily.
Gender differences — Established recommendations for safe levels of drinking do not address an "ideal" level of alcohol consumption. However, they advise
●No more than two drinks daily for men
●No more than one drink daily for women
What is the best approach in my case? — The following guidelines may help in making an informed decision about alcohol use:
●Consult a healthcare provider to determine the specific risks and benefits of alcohol use. Multiple factors must be considered in any such "risk-benefit analysis," including age, sex, personal medical history, family history, diet, physical fitness, and certain lifestyle choices such as smoking, among others.
●Women should not drink any alcohol during pregnancy; in addition, experts advise that women should stop drinking when trying to conceive.
●Never consume alcohol before or while driving or operating any potentially dangerous equipment.
WHERE TO GET MORE INFORMATION
Your healthcare provider is the best source of information for questions and concerns related to your medical problem.
This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.
Patient level information — UpToDate offers two types of patient education materials.
The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.
Patient education: Alcohol use — when is drinking a problem? (The Basics)
Patient education: Alcohol poisoning (The Basics)
Patient education: Alcohol withdrawal (The Basics)
Patient education: Marijuana use and addiction (The Basics)
Patient education: Fetal alcohol syndrome (The Basics)
Patient education: Cocaine use disorder (The Basics)
Patient education: Alcohol and drug use in pregnancy (The Basics)
Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.
Patient education: Alcohol use — when is drinking a problem? (Beyond the Basics)
Patient education: High blood pressure in adults (Beyond the Basics)
Patient education: Heart attack recovery (Beyond the Basics)
Patient education: Peripheral artery disease and claudication (Beyond the Basics)
Patient education: Factors that modify breast cancer risk in women (Beyond the Basics)
Patient education: Cirrhosis (Beyond the Basics)
Patient education: Hepatitis C (Beyond the Basics)
Patient education: Gallstones (Beyond the Basics)
Patient education: Acute pancreatitis (Beyond the Basics)
Patient education: Chronic pancreatitis (Beyond the Basics)
Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.
Ambulatory management of alcohol withdrawal
Cardiovascular benefits and risks of moderate alcohol consumption
Clinical manifestations and diagnosis of alcoholic fatty liver disease and alcoholic cirrhosis
Hepatitis C and alcohol
Identification and management of unhealthy alcohol use in the perioperative period
Management of moderate and severe alcohol withdrawal syndromes
Overview of the chronic neurologic complications of alcohol
Overview of the risks and benefits of alcohol consumption
Pathogenesis of alcoholic liver disease
Psychosocial treatment of alcohol use disorder
Substance misuse in pregnant women
Screening for unhealthy use of alcohol and other drugs in primary care
The following organizations also provide reliable health information.
●National Library of Medicine
●National Institute on Alcohol Abuse and Alcoholism (NIAAA)
●American Academy of Family Physicians
- International Center for Alcohol Policies; International drinking guidelines, 2003. http://www.icap.org/LinkClick.aspx?fileticket=KtXj8PGibT8%3D&tabid=75 (Accessed on June 13, 2012).
- Pearson TA, Terry P. What to advise patients about drinking alcohol. The clinician's conundrum. JAMA 1994; 272:967.
- Zhang SM, Lee IM, Manson JE, et al. Alcohol consumption and breast cancer risk in the Women's Health Study. Am J Epidemiol 2007; 165:667.
- Leon DA, Saburova L, Tomkins S, et al. Hazardous alcohol drinking and premature mortality in Russia: a population based case-control study. Lancet 2007; 369:2001.
All topics are updated as new information becomes available. Our peer review process typically takes one to six weeks depending on the issue.