Moderate Alcohol Consumption: Good, Bad or No Big Deal?

So much has been written regarding the effect of moderate alcohol consumption on overall health and cognitive function. Most of the research was culled from various large epidemiological studies such as the Framingham data on health risk. There are, however, numerous variables and confounding factors involved when studying a behavior as common as alcohol consumption.

What is moderate alcohol consumption?

For healthy adults, moderate alcohol use means up to one drink a day for women of all ages and for men older than age 65—and no more than two drinks a day for men age 65 and younger.

Examples of one drink include:

  • Beer: 12 fluid ounces (355 milliliters)
  • Wine: 5 fluid ounces (148 milliliters)
  • Distilled spirits (80 proof): 1.5 fluid ounces (44 milliliters)

In 2016, the Mayo Clinic consumer website reported the potential benefits of moderate alcohol use:

  • Alcohol may reduce your risk of ischemic stroke (when the arteries to your brain become narrowed or blocked, causing severely reduced blood flow)
  • Alcohol may reduce your risk of diabetes

In a recent well-powered and well-designed study by Topiwala et al (2017), researchers looked at the brains of over 500 adults to assess structural brain changes including atrophy of the hippocampus, white matter microstructure and grey matter density. Functional measures included cognitive decline and cross sectional cognitive performance at the time of brain scanning procedures. Ask the Expert

The results were eye opening. Study participants with higher alcohol consumption during the 30-year follow-up revealed a dose dependent association with hippocampal atrophy. The hippocampus is critical to sorting, storing and retrieving information. Consumption of over 30 units of alcohol per week was associated with the highest risk when compared to those who abstain from alcohol (OR 5.8, 95% confidence interval 1.8 to 18.6; P≤0.001), even those drinking moderately (14-21 units/week) were three times as likely to have right sided hippocampal atrophy 3.4, 1.4 to 8.1; P=0.007).

Contrary to public opinion over the past decade, the research demonstrated no protective effect of light drinking (1-<7 units/week) over abstinence. In addition, higher alcohol use produced differences in corpus callosum microstructure and increased decline in lexical fluency and no association was found in cognitive performance or longitudinal changes in language fluency or recall.

In contrast to numerous reports, moderate alcohol consumption is associated with hippocampal atrophy and other neural pathologies. These findings support the most recent increase in public health education regarding alcohol use in the U.K. while casting some doubt on the current alcohol use recommendations in the U.S.

Although the question of health benefit and disease protection has been the subject of great debate and some controversy in the U.S., the adverse effects of alcohol use for specific persons or persons with certain pathophysiology have been established.

For example, alcohol should be avoided:

  • During pregnancy or when trying to become pregnant
  • When a diagnosis with alcohol or drug use disorder has been established, or when one has a family history of addictive disease
  • By those with liver or pancreatic disease
  • By those with heart failure or have a weakened heart
  • By those taking a prescription or over-the-counter medications that are contraindicated with alcohol
  • By those who have had a hemorrhagic stroke

Why Does This Matter?

Harvard’s Dr. Eric Rimm and others have reported that a number of studies have shown moderate alcohol consumption to have some health benefits and protective factors such as increased cardiovascular health and longevity. These data, plus the so-called French paradox, have contributed to the notion that moderate alcohol drinking was, at worse benign, and perhaps an effective anti-aging, performance enhancing substance when used moderately. However, the excellent research and analysis by Topiwala and colleagues suggest otherwise and should be taken seriously as the prevalence of alcohol use, alcohol use disorder and mortality among U.S. citizens and especially among our seniors is increasing.

1. Topiwala A, et al. Moderate alcohol consumption as risk factor for adverse brain outcomes and cognitive decline: longitudinal cohort study. BMJ. 2017 Jun 6;357:j2353. doi: 10.1136/bmj.j2353