Sorting out the health effects of alcohol

Robert H. Shmerling, MD

Senior Faculty Editor, Harvard Health Publishing

When it comes to your beverage of choice, alcoholic beverages are unique. For millions, they are a regular part of the dining experience. They’re often an important component of social events, celebrations, and milestones; we toast people, events, and memories with alcohol. They play a key role in many religious traditions. And, of course, the alcoholic beverage industry is a major economic force, responsible for more than $250 billion in sales annually in the US.

And all of this is true despite the well-known and well-publicized risks of drinking too much alcohol.

The negative effects of alcohol

It should be a surprise to no one that drinking too much alcohol can be bad for you — of course, the definition of “too much” can vary. More on that in a moment.

Here are some of the more common negative health consequences of excessive alcohol consumption — and good reasons to moderate your intake of alcohol:

  • liver disease, including cirrhosis and life-threatening liver failure requiring a liver transplant
  • a higher risk of high blood pressure, heart failure, and dementia
  • a higher risk of certain cancers, including those of the digestive tract (including colon cancer), breast, and liver
  • a higher risk of injury, especially from drunk driving and falls — homicides and suicides are also often alcohol-related
  • lapses in judgement — For example, people who are drunk may engage in risky sexual behavior or use other drugs
  • a higher risk of depression, anxiety, and addiction which may, in turn, affect one’s ability to establish and maintain social relationships and employment
  • alcohol poisoning — many people don’t realize that if you drink enough alcohol over a short period of time, it can be fatal
  • fetal alcohol syndrome — alcohol can damage a baby’s developing brain and cause other developmental abnormalities.

Excessive alcohol consumption can cause health problems not only for the drinker, but also for their family, friends, coworkers, and employers.

Are there benefits of alcohol?

While the list of health risks related to excessive alcohol consumption is long, there may also be health benefits associated with moderate drinking. There’s the psychological or social impact of alcohol. Having a drink while getting together with family or friends can be helpful to relieve stress and promote a sense of well-being. Alcohol has long been considered a “social lubricant” because drinking may encourage social interaction. These benefits are hard to measure.

In addition, studies suggest that moderate drinking (as discussed below) may be linked with a lower risk of:

  • heart attack
  • the most common type of stroke
  • death due to cardiovascular disease
  • diabetes

Despite these potential health benefits, most doctors don’t recommend that someone who doesn’t drink start drinking, or for a moderate drinker to drink more. That’s because these are only correlations (which does not necessarily mean causation). Many of these benefits are quite small, and it’s hard to predict who will actually benefit and who may be harmed more than helped by alcohol consumption.

How much alcohol consumption is too much?

The answer has varied over time, but a widely accepted definition of moderate alcohol consumption — as endorsed by the US Department of Health and Human Services and the US Department of Agriculture — is one drink or less per day for women or two drinks or less per day for men. The lower recommendation for women isn’t just because they are, on average, smaller than men. It turns out alcohol affects women differently. They produce less of the enzyme (called alcohol dehydrogenase, or ADH) that breaks down alcohol. In addition, women tend to have more body fat, which tends to retain alcohol.

The definitions for “a drink” in the US are the common serving sizes for beer (12 ounces), wine (5 ounces), or hard liquor (1.5 ounces).

Meanwhile, “high risk” drinking is considered:

  • four or more drinks in one day or eight or more drinks per week for women
  • five or more drinks in one day or 15 or more drinks per week for men
  • Binge drinking is defined as four or more drinks over two hours for women and five or more drinks over two hours for men.

A new study could change what’s considered moderate drinking

A new study analyzed data from nearly 600,000 people who drank at least some alcohol, and monitored their health over time. They found that regardless of gender, higher alcohol consumption was associated with a higher rate of stroke, fatal aneurysms, heart failure, and death. When compared with people who drank less than seven drinks per week:

  • Adults drinking seven to 14 drinks per week could expect, on average, a six-month shorter life expectancy as of age 40
  • Those drinking 14 to 25 drinks per week could expect a shorter life expectancy by one to two years
  • Those drinking more than 25 drinks per week could expect a shorter life expectancy by four to five years

Depending on the country, current guidelines (including those in the US) could allow levels of drinking high enough to shorten life expectancy.

Is drinking some alcohol better than not drinking it at all?

The study described above examined how much alcohol consumption might be too much. But is there a health advantage to at least some drinking? Another recent study says yes. Light drinkers (those consuming one to three drinks per week) had the lowest rates of cancer or death compared to those drinking less than 1 drink per week.

The bottom line on the health effects of alcohol

There are important limitations to research on alcohol consumption. Most rely on self-reporting, do not analyze binge drinking, do not assess alcohol consumption over a lifetime, or do not account for the fact that some study subjects may reduce their alcohol consumption due to alcohol-related health problems. Still, this new research is among the best we have linking what is commonly considered moderate drinking to negative health consequences.

These findings may lead to a revision in guidelines. Do people pay attention to these guidelines? And even more importantly: how can the social and physical benefits of light drinking be maintained while minimizing risk? Stay tuned. The next big study on alcohol could answer these questions.

Related Information: Alcohol Use and Abuse


  1. Robert Shmerling

    There may be a mixed message regarding alcohol consumption because, in fact, the effects of alcohol on health are complex – just how much is too much continues to be debated.

    But even if there was a consensus that light drinking was beneficial or “medicinal,” most doctors might not recommend alcohol to non-drinkers because it is not easy to know who will drink too much, drive while intoxicated, etc. – it is hazardous to make individual recommendations based on a population-based, observational studies that combine data from thousands of individuals.

    In addition, it’s worth acknowledging that doctors tend to worry about liability – that alone might dampen enthusiasm of recommending light drinking, regardless of what the data shows!

  2. Rachel Courtney

    I’m not a drinker, don’t like it. I’ll have a few drinks a year, at a special occasion to “fit in” and be “sociable”. Never feels that good, and I don’t sleep well that night.

    The mixed messages here are tough to sort out.

    First you write:
    “Despite these potential health benefits, most doctors don’t recommend that someone who doesn’t drink start drinking”

    WHY? Because then you write:
    “Light drinkers (those consuming one to three drinks per week) had the lowest rates of cancer or death compared to those drinking less than 1 drink per week.”

    SO maybe it has a medicinal benefit, and all should consider including it as a part of a balanced healthy diet?

  3. Mike Stanhill

    Great article and informative comments. Thanks

  4. Edie Raether, MS, CSP

    You had nothing really on the effects on the brain. Check out Daniel Amen’s work and studies on that. One of his bestsellers is Change Your Brain…Change Your Life. He does not touch the stuff! And his research asks why one would take even a moderate amt. of poison? I do have about a third of a glass with dinner, but am very moderate….just to play safe!

  5. Ramón Narvaez

    Check out this point of view. Got me thinking twice!

    Any ideas?

  6. Robert Shmerling

    While there was a linear association between cancer and alcohol consumption, I was referring to the finding of the study that assessed the outcome combining risk of cancer or death as stated by the study authors. Specifically; There was a “J-shaped association observed between average lifetime alcohol consumption and overall mortality, cardiovascular- related mortality, and combined risk of death or cancer.”

    So, from in the Kunzmann study, for these measures, never-drinkers had higher risk compared to lifetime light drinkers.

    Though the message of ‘less alcohol is better’ is easy, it may not be true.

  7. Miguel Marcos

    It is an interesting post but the study of Kunzmann et al clearly states that “Analyses of specific causes of mortality revealed (…) a linear association for cancer-related mortality”, therefore I think it is a bit misleading saying that “Light drinkers had the lowest rates of cancer or death compared to those drinking less than 1 drink per week.” Also, this same study clearly states: “This evidence should not be taken to support a protective effect of light drinking.” Alcohol, less is better. Easy message as far as we know right now.

  8. catalina laserna

    Great information! Could you provide the specific reference to the article about how age affects the effect of alcohol? thanks!

  9. Cliff gallant

    I was surprised that the article didn’t include the age related effects of alcohol. I read recently that , because the rate of metabolism has slowed down, the effects of alcohol on a 60–70 year old are twice as pronounced as the effects on a 30-40 year old. If a senior citizen is drinking two or more drinks a day their focus and energy level is dramatically affected.

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