Most nutrition experts would agree that a holiday cocktail or midnight toast on New Year’s Eve is not likely to affect one’s overall health — assuming the imbiber is not in a group that should avoid alcohol, such as pregnant or breast-feeding women, children, people with certain health conditions or those who are taking medications that may interact. But there is a new wave of skepticism about studies suggesting potential benefits of drinking alcohol and prompting headlines such as “11 Ways Alcohol Is Legitimately Healthy” (Greatest.com, 2012) to “8 Reasons Drinking Alcohol Is Actually Good for You” (Shape, 2015).
At the center of the debate is a J-shaped curve representing the relationship between alcohol consumption and mortality, with abstainers and heavy drinkers having higher mortality risk than light-to-moderate drinkers. In 2003, a high-profile systematic review of the health risks and potential benefits of moderate alcohol consumption supported this relationship regarding coronary heart disease and ischemic stroke. Other researchers observed similar J-shape curves with respect to risks for Type 2 diabetes, hearing impairment, hip fractures, dementia, liver cirrhosis and other conditions.
However, a steady stream of scientists has been raising questions about the quality of these studies. In particular, a 2016 meta-analysis reports many researchers did not differentiate between the kinds of “abstainers” (the group to which moderate and heavy drinkers were compared). Specifically, those who had never consumed alcohol, those who had previously consumed alcohol but since stopped, and those who did not consume alcohol every day but did so on occasion, often were lumped into the same samples.
Furthermore, critics assert that “abstainers” who are former drinkers often stop consuming alcohol because of sickness or frailty — suggesting this group may be biased toward ill health. A 2009 meta-analysis of studies in which “abstainers” referred exclusively to lifelong abstainers (and did not include former or occasional drinkers) found them to be at equal risk for all-cause and cardio mortality as “light” or “moderate” drinkers.
Other cohort study challenges include accounting for genetic predisposition, body size or shape, metabolism and lifestyle factors such as smoking, eating patterns and physical activity. On the flip side, many of the same challenges exist for cohort studies investigating causal relationships between alcohol consumption and disease, including various types of cancers. This becomes even more complicated when studying beverage-specific effects on health, since populations who drink mainly wine (or beer or another form of alcohol) likely will be impacted by other cultural influences, socioeconomic status and access to regular health care.
What everyone does seem to agree upon are the significant health risks associated with overconsumption of alcohol and binge-drinking — neither of which is unheard of during certain celebrations or holiday seasons. So for now, alcohol messaging remains largely unchanged: Enjoy a holiday libation, but do so in moderation.