“The committee [The National Academies of Sciences, Engineering, and Medicine (NASEM) convened a multidisciplinary committee of individuals with expertise in alcohol exposure measurement, the relevant clinical outcomes, epidemiology, evidence synthesis, previous experience with the 2025 Dietary Guidelines for Americans, and public health] evaluated the associations between moderate alcohol consumption (defined in previous DGA versions as 1 drink or 14 g of alcohol per day for women and 2 drinks or 28 g of alcohol per day for men) and all-cause mortality, weight changes, certain types of cancer, cardiovascular disease, and neurocognition. [..]
The standard drink size of 14 g of alcohol from any beverage type is also a challenge; the sizes of a serving of both wine and beer have increased over time in many settings, as has the alcohol content, especially in beer. Other challenges for exposure measurement include variation in beverage type (wine, beer, spirits) that may be associated with other substances in the beverage as well as in differences in drinking patterns, such as drinking with meals or drinking several drinks on fewer days. Variability in food frequency questionnaires used to measure alcohol consumption further complicates exposure measurement. The evidence available to the committee did not allow meaningful evaluation of these issues regarding alcohol exposure.
An important source of potential bias involves the inclusion of former drinkers in the nondrinker comparison group, creating the potential for abstainer bias, which arises when individuals who stopped drinking due to health reasons (such as an alcohol-related or sensitive disease, including alcohol use disorder) are included with never drinkers. This combined comparison group of never drinkers and former drinkers may be less healthy than the exposed group, accounting for a benefit associated with moderate drinking. Cognizant of this important potential source of bias, the committee excluded studies that included former drinkers in the comparison group. We also excluded studies of binge drinking as being out of scope for the report. These decisions decreased the number of eligible studies for the systematic reviews but improved the rigor of the evidence base considered.
Other analytic challenges include adequate consideration of confounders and effect modifiers, such as age, sex, menopausal status, genetic ancestry, socioeconomic status (SES), and diet; future research should address these issues. For example, men metabolize alcohol more quickly than women do, so the health impacts are different, which has led to different definitions of moderate drinking. There are differences in breast cancer risk before and after menopause, and there may also be differences in alcohol consumption based on age and menopausal symptoms. There are differences in alcohol metabolism based on genetic ancestry (eg, European, East Asian) and associated differential alcohol consumption patterns. SES could confound the relationship in either direction; individuals with higher SES may have differential access to alcohol and to other health determinants, and individuals with lower SES may have additional health challenges, including higher risk of worse mental health and more substance use.
[..] Although no high-certainty conclusions could be made regarding associations between alcohol and specific outcomes, the committee made 3 conclusions with moderate certainty. Moderate certainty implies that “as more information becomes available, the magnitude or direction of the observed effect could change, and this change may be large enough to alter the conclusion.” The committee’s 3 moderate-certainty conclusions were:
- Moderate alcohol consumption is associated with a lower risk of all-cause mortality.
- Moderate alcohol consumption is associated with a lower risk of cardiovascular disease mortality.
- Moderate alcohol consumption is associated with a higher risk of (female) breast cancer.
[..] Subsequent studies and guidance following the release of the report used different methods and decision processes and are not directly comparable to the findings of the report. Perhaps the most high-profile release was the US Surgeon General’s advisory entitled Alcohol and Cancer Risk. This advisory summarized cancer risk across all intake levels, so it is not comparable with the NASEM report. However, at least for (female) breast cancer, where the recent evidence was sufficient, the report was consistent with the advisory in concluding that moderate drinking was associated with an increased risk. Note that for other cancers, the evidence evaluated in the report was insufficient, which does not mean that there is not an increased risk with moderate consumption but rather that additional research is needed. In fact, when examining the association of moderate alcohol (or any exposure) with any outcome, it is critical to remember that insufficient evidence for an association is not equivalent to evidence of no association and that there may well be additional beneficial and harmful associations between moderate alcohol consumption and health.
[..] Stepping out of the formal role on the NASEM study committee, the authors of this Perspective assert that there is insufficient evidence to support recommending any level of alcohol use to improve health. Clinicians should recognize the complex relationship between moderate alcohol consumption and health and should continue to ask patients about alcohol intake and provide guidance and support for adhering to authoritative, evidence-based recommendations regarding alcohol consumption.”
Full article, N Calogne, IJ Saldanha and KB Stone, JAMA, 2025.9.30