Is moderate drinking really safe? New research raises doubts

To better understand how different drinking patterns influence cancer risk, the research team conducted a large systematic review of existing evidence. They analysed 62 studies involving sample sizes ranging from just 80 participants to nearly 100 million people, focusing on US adults. The review examined excessive, moderate, and low levels of alcohol use while also accounting for co-existing conditions such as obesity and chronic liver disease, which are known to heighten cancer risk.

The analysis revealed consistent links between alcohol use and cancers of the breast, colorectal region, liver, mouth, larynx, oesophagus and stomach. Both drinking frequency and total intake played significant roles. Alcohol use was also associated with worse outcomes for people already living with conditions such as alcoholic liver disease, including more advanced liver cancer and lower survival rates.

“Across 50 studies in our review, higher alcohol consumption consistently raised cancer risk, with risk increasing as intake grows,” Lea Sacca, an assistant professor of population health and senior author of the study, was quoted as saying by the News Medical website. “Heavy, daily or binge drinking is strongly linked to multiple cancers, highlighting the importance of moderation and following cancer prevention guidelines.”

Unequal risks across populations

One of the review’s most striking findings was that alcohol-related cancer risk is not evenly distributed. Higher levels of drinking were linked to particularly elevated risk among African Americans, people with certain genetic predispositions, and individuals with obesity or diabetes. Age, race, education, and income also shaped exposure and vulnerability.

In some lower-socioeconomic groups and racial or ethnic communities, the burden of alcohol-related cancer was disproportionate even when overall alcohol consumption was similar to, or lower than, that seen in other populations. These patterns point to broader structural and health-related factors that can magnify alcohol’s effects.

By contrast, individuals who followed American Cancer Society recommendations on alcohol use and adopted other healthy lifestyle behaviours tended to have lower cancer risk and reduced mortality. The findings suggest that alcohol should not be viewed in isolation but as part of an interconnected set of habits and health conditions.

Does the type of drink matter?

The review also explored whether different alcoholic beverages carry different risks. In several studies, beer and white wine were associated with a higher risk for certain cancers, while liquor was not consistently linked to the same outcomes. The reasons for these differences remain unclear and may reflect patterns of consumption rather than the drinks themselves.

Clear gender differences also emerged. Among men, frequent drinking was more strongly associated with increased cancer risk. Among women, episodic heavy drinking, such as consuming large amounts in a short period, was especially concerning. Smoking further amplified alcohol-related cancer risk, although its impact varied depending on sex and the level of alcohol use.

Other factors shown to intensify risk included ultraviolet exposure, which was linked to melanoma in less sun-exposed areas, and family history of cancer. Across the studies, additional contributors ranged from very high or very low body mass index and low physical activity levels to poor diet, hormone use, and certain infections, including hepatitis B and C, HPV, HIV, and H. pylori.

How alcohol affects the body

The biological mechanisms behind these associations are well documented. Alcohol is metabolised into acetaldehyde, a toxic compound that can damage DNA. It can also disrupt hormone levels, trigger oxidative stress, weaken immune responses and increase the body’s absorption of other carcinogens.

“Biologically, alcohol can damage DNA through acetaldehyde, alter hormone levels, trigger oxidative stress, suppress the immune system, and increase carcinogen absorption,” Lewis S. Nelson, co-author of the study and dean of health affairs at the college, was quoted as saying by News Medical. “These effects are compounded by pre-existing health conditions, lifestyle choices, and genetic predispositions, all of which can accelerate cancer development.”

Rethinking prevention and policy

Based on their findings, the researchers argue that reducing alcohol-related cancer risk requires more than blanket advice to “drink less”. They call for targeted public health messaging, stronger alcohol-related policies, and focused interventions aimed at groups facing the highest risk.

“Our findings underscore that alcohol-related cancer risk is not driven by alcohol alone, but by a complex interplay of biological, behavioural, and social factors,” Maria Carmenza Mejia, a co-author and professor of population health, was quoted as saying by the website. “Recognising how these forces intersect, shaping exposure, vulnerability and long-term health outcomes is essential for building a more accurate understanding of cancer risk.”

As festive gatherings approach, the research, published in the journal Cancer Epidemiology, serves as a timely reminder that even moderate drinking is not risk-free. While alcohol remains a common part of social life, evidence suggests that informed choices and broader support for healthier environments may play an important role in lowering cancer risk over the long term.