Modifying factors relating to moderate drinking of alcoholic beverages and cancer risk
In a commentary, Edward Giovannucci (Department of Nutrition and Epidemiology, Harvard TH Chan School of Public Health) argued that consuming high levels of alcoholic beverages are recognised as harmful, the effects of low-to-moderate drinking (up to 2 drinks/day for men and 1 for women, 14 g of alcohol/drink) remain debated. Some studies suggested health benefits such as reduced cardiovascular disease and type 2 diabetes risk. However, these benefits are contested, and growing evidence showed that even modest use of alcoholic beverages can increase the risk of certain cancers (i.e. breast cancer in women). 25% of global alcohol-related cancer cases in 2020 occurred in individuals drinking at moderate levels. In moderate drinkers, four modifying factors merit consideration:
- tobacco use,
- drinking frequency,
- whether drinking is with meals or on an empty stomach, and
- beverage type.
Smoking significantly increases the cancer risks associated with alcohol. A synergistic effect between alcohol and tobacco raises acetaldehyde levels and cancer risk, especially for upper aerodigestive tract cancers. Among non-smokers, moderate consumption of alcoholic beverages contributes relatively little to cancer risk, particularly in men. In women, there may an increased risk even without smoking (because of breast cancer). These differences underline the need to assess alcohol-related cancer risk in the context of tobacco use.
How the alcoholic beverages are consumed—regularly with meals versus infrequent binge drinking—substantially affects health outcomes. People with a “favourable” drinking pattern (regular, moderate intake with meals) show lower cancer and mortality risks compared to those with “unfavourable” patterns (e.g., binge drinking). Timing and frequency influence the body’s metabolic response and the exposure of organs to alcohol, particularly in the gastrointestinal tract.
Different types of alcoholic beverages may influence cancer risk differently. Red wine contains phenolic compounds like resveratrol that may offer protective effects against oxidative stress and metabolic dysfunction. Observational and interventional studies suggest that red wine may be less harmful—or even beneficial—in some contexts compared with liquor or beer.
The author concludes that current public health recommendations often generalise the risk of alcohol by average daily intake, without accounting for key modifiers such as smoking, drinking patterns, meal timing, and beverage type. These factors can significantly alter the relationship between alcoholic beverages and cancer risk. For truly informed guidance on low-to-moderate intake of alcoholic beverages, future research must better account for these variables and explore biologically plausible mechanisms, rather than relying on simplistic dose–response models.
