Health risks and benefits of alcohol

    7:06 AM, Dec 31, 2012   |    comments
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    LITTLE ROCK, Ark. (KTHV) -- Is alcohol good for your health? For many reasons, this is a question without simple or clear-cut answers.

    Humans have used alcohol safely and enjoyably for thousands of years, and it continues to occupy an important place in many religious ceremonies and social celebrations. In addition, moderate alcohol use can provide certain health benefits, particularly with regard to coronary heart disease.

    However, alcohol consumption is also associated with serious risks. Drinking too much alcohol contributes to accidents and injuries and can lead to liver disease, certain types of stroke, high blood pressure, various cancers, and birth defects, among other health problems. Thus, 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 information: 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)

    In general, studies that evaluate the health effects of alcohol designate different drinking patterns (eg, heavy, moderate, or light drinking) based upon the number of drinks consumed per day or week. Moderate drinking is generally defined as 3 to 9 servings of alcohol per week.

    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 [1].

    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) and the most common type of stroke (ischemic stroke) by 25 to 40 percent.

    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 information: 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.

    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.

    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. 

    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.

    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.

    Cirrhosis - Low levels of alcohol do not clearly cause cirrhosis. Heavy drinking (at least five drinks daily) is generally required to cause cirrhosis in men.

    Gallstones - Moderate alcohol use has been shown to lower the risk of gallstones. However, heavy drinking may reverse this benefit. 

    Pancreatitis - Heavy drinking increases the risk of both sudden (acute) and long-term (chronic) inflammation of the pancreas (pancreatitis).

    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. 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. However, moderate drinking does not appear to raise 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 abstainers who begin drinking 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 substantially reduce the risk of dying. 
    - 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) 
    - Are pregnant? 
    - Have a personal or strong family history of alcoholism?
    - Have a personal or strong family history of breast cancer? 
    - Have had hemorrhagic stroke?
    - Have liver or pancreatic disease? 
    - 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.

    An "ideal 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. 
    - If drinking alcohol is appropriate, follow recommended guidelines concerning moderate drinking, ie, limiting intake to no more than one drink daily for women or two drinks daily for men. 
    - 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. 
    - Speak with your child's doctor about preventing alcohol use and abuse in children and teenagers. Unfortunately, Americans are commonly introduced to alcohol during adolescence, around the same time that they are introduced to automobiles; this can be a deadly combination.

    Adults should model responsible drinking for children and adolescents by either abstaining from alcohol or drinking in moderation. Clearly, children exposed to alcohol abuse in their parents are more likely to become alcoholic themselves.

    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.

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