The National Academies of Sciences, Engineering, and Medicine recently released a pivotal report examining the health impacts of moderate alcohol consumption. Requested by Congress, this report is intended to inform the next edition of the Dietary Guidelines for Americans (DGA), which shapes national nutrition policy and public health recommendations. This marks the first comprehensive review of alcohol and health in the DGA since 2010.
Among the experts shaping this comprehensive review is Susan Smith, PhD, a principal investigator at the UNC Nutrition Research Institute. “Although alcohol isn’t a nutrient, it contributes 3-5% of calories to a typical adult diet. While the adverse consequences of high alcohol consumption are clear, its influence at moderate intakes is less certain and potentially affects the health of many Americans,” states Smith.
Smith served on the committee tasked with evaluating the latest evidence on moderate alcohol consumption—defined as no more than one drink per day for women and no more than two drinks per day for men. One drink is equivalent to approximately 14 grams of pure alcohol (e.g., a 5-ounce glass of wine, a 12-ounce beer, or a 1.5-ounce shot of distilled spirits). The committee’s focus was on moderate consumption because the adverse health consequences of higher intakes are already well known. The report did not evaluate pregnancy-related outcomes, as women who are pregnant should not drink alcohol.
The committee’s analysis covered eight key health outcomes, including weight changes, cardiovascular disease, cognitive function, and several types of cancer. One groundbreaking aspect of this work was disentangling the influence of “never drinkers” from “former drinkers.” Former drinkers often quit due to poor health, which can skew findings to make moderate drinking appear healthier than it is.
The report’s findings included:
- Cancer Risk: Moderate alcohol consumption is associated with an increased risk of certain cancers, most notably breast cancer.
- Cardiovascular Disease: Moderate intake is associated with a lower risk of cardiovascular disease.
- Weight Changes: Moderate consumption might be associated with lower weight gain with age in women but increased weight gain in men.
- Cognitive Decline: Evidence was insufficient to evaluate any association between moderate drinking and cognitive decline.
“Moderate alcohol consumption has complex effects. People should consider their own health history and health risks in thinking about these potential effects of alcohol,” explains Smith. “A person should never start drinking in the belief it will ‘improve’ health. A surer choice is to eat healthy and exercise.”
The report also emphasized the challenges of accurately measuring alcohol consumption due to underreporting and recommended developing better methodologies. Furthermore, the findings are not definitive because the outcomes may be influenced by other lifestyle factors. Notably, individuals who consume alcohol in moderation are more likely to have higher incomes and better access to health care.
The committee identified significant gaps in current research and called for future studies to:
- Include more women and analyze sex-specific effects.
- Consider life stages such as post-menopause and childbearing years.
- Include more diverse populations to ensure findings are broadly applicable.
Smith’s expertise played a vital role in interpreting the data and refining the report’s conclusions. Her involvement underscores the UNC Nutrition Research Institute’s leadership in tackling complex public health issues. As these findings inform the upcoming Dietary Guidelines for Americans, they are expected to shape not only federal policy but also individual choices about alcohol consumption.
Susan Smith, PhD, a professor of Nutrition at the UNC Nutrition Research Institute, studies how prenatal alcohol exposure (PAE) impacts fetal development, focusing on the interplay between nutrition, genetics, and environmental factors. Her research, recognized by a prestigious MERIT award from the National Institute on Alcohol Abuse and Alcoholism (NIAAA), has uncovered molecular pathways that drive alcohol-induced developmental defects and identified maternal risk factors like iron deficiency that heighten vulnerability to PAE-related outcomes.
