Author: Charles Frank

New genetic study confirms that alcohol is a direct cause of cancer Nuffield Department of Population Health

As with most questions related to a specific individual’s cancer treatment, it is best for patients to check with their health care team about whether it is safe to drink alcohol during or immediately following chemotherapy treatment. The doctors and nurses administering the treatment will be able to give specific advice about whether it is safe to consume alcohol while undergoing specific cancer treatments. The plant secondary compound resveratrol, found in grapes used to make red wine and some other plants, has been investigated for many possible health effects, including cancer prevention.

Another enzyme, called aldehyde dehydrogenase 2 (ALDH2), metabolizes toxic acetaldehyde to nontoxic substances. Some people, particularly those of East Asian descent, carry a variant of the gene for ALDH2 that encodes a defective form of the enzyme. In people who produce the defective enzyme, acetaldehyde builds up when they drink alcohol. But most Americans aren’t aware of this link, thanks to seemingly contradictory research and mixed messaging from public health experts. A study published in 2023 found widespread mistaken beliefs that the risk varies by beverage type, with the lowest cancer risk assigned to wine. Another study published in 2021 showed that nearly 70% of people did not even know that alcohol was a cancer risk factor.

1. The study also found that people who believed drinking alcohol increased the risk of heart disease were more aware of the alcohol–cancer risk than those who were unsure or believed drinking lowered the effect on heart risk.
2. “We need to better understand these root causes and how best to address them,” she said.
3. Studies have shown that “high-risk behaviors are higher in [AYA] survivors,” Dr. DuVall said.
4. Because these alleles are allocated at birth and are independent of other lifestyle factors (such as smoking), they can be used as a proxy for alcohol intake, to assess how alcohol consumption affects disease risks.

More research is needed to understand some of the disparities seen in this study, such as with age, Dr. LoConte said. Alcoholic beverages may also contain a variety of carcinogenic contaminants that are introduced during fermentation and production, such as nitrosamines, asbestos fibers, phenols, and hydrocarbons. Studies have shown that “high-risk behaviors are higher in [AYA] survivors,” Dr. DuVall said. That said, Dr. DuVall continued, high alcohol use in AYAs who have or had cancer is not necessarily surprising.

Awareness varies by beverage type

But the All of Us study, Dr. Cao and her colleagues explained, offered a unique opportunity to take a robust look at people in these groups in the United States. For people with early-stage lung cancer, quitting also delays the cancer’s return. The results, the study team argued, should be a wake-up call for all those involved in cancer care.

Some studies show that drinking three or more alcoholic drinks per day increases the risk of stomach and pancreatic cancers. There is also evidence that drinking alcohol increases the risk for prostate cancer. All alcoholic drinks, including red and white wine, beer, and liquor, are linked with cancer. For people being treated for cancer, regularly consuming a few beers or cocktails also has other potentially harmful consequences, including making their treatments less effective.

Evidence from Western countries already strongly indicates that alcohol is a direct cause of cancer in the head, neck, oesophagus, liver, colon and breast. But it has been difficult to establish whether alcohol directly causes cancer, or if it is linked to possible confounding factors (such as smoking and diet) that could generate biased results. It was also unclear whether alcohol is linked to other types of cancer, including lung and stomach cancers. Worldwide, alcohol may cause around 3 million deaths each year, including over 400,000 from cancer.

More cancers could be prevented, she says, if people fully understood the risks of alcohol. Understanding these risks would lead to more fully informed decisions about alcohol use among individuals and families, including cancer survivors and those with a family cancer history. The public is largely unaware of the link between alcohol consumption and increased cancer risk. Using the data from All of Us does come with some limitations, they acknowledged, including that cancer diagnoses were self-reported and couldn’t be verified in every case. And because of the study’s nature, it can also create certain “biases” in the data that may affect its accuracy or how relevant it is to the larger population of people with cancer and long-term survivors. Overall, about 12,000 people in this group reported that they drink alcohol, and nearly 40% reported engaging in hazardous drinking—that is, repeated excessive alcohol use.

These increased risks are seen only among people who carry the ALDH2 variant and drink alcohol—they are not observed in people who carry the variant but do not drink alcohol. The study confirmed that most American adults aren’t aware of the link between alcohol consumption and cancer. It also found that, even among those who are aware, there’s a belief that it varies by the type of alcohol. For example, more participants were aware of the cancer risks from hard liquor and beer than about the risk from wine, with some participants believing wine lowers your cancer risk.

Why Aren’t People Aware of the Cancer Risk From Drinking?

To conduct the study, the researchers used data from more than 15,000 people with a history of cancer who were participating in the National Institutes of Health All of Us Research Program. The first mutation is a loss-of-function mutation in the gene for the enzyme aldehyde dehydrogenase 2 (ALDH2). A person’s risk of alcohol-related cancers is influenced by their genes, specifically the genes that encode enzymes involved in metabolizing (breaking down) alcohol (27). New data from a large-scale genetic study led by Oxford Population Health confirms that alcohol directly causes cancer. Launched in 2018, All of Us captures information on participants’ lifestyle and other behaviors and personal background via comprehensive surveys. Participants can also allow access to their electronic health records (with all identifying information removed), providing important insights on treatments received and other relevant health information.

With alcohol consumption rising, particularly in rapidly developing countries such as China, there is an urgent need to understand how alcohol affects disease risks in different populations. The researchers cited the change in public perceptions and tighter regulations for tobacco, which show the importance of public health campaigns and physicians explaining risks to their patients. Dr. Klein noted, “[In] less than half a century, we’ve seen major changes in the way people think about tobacco.”

Public health campaigns about the cancer risk posed by alcohol in England and Australia have been effective at raising awareness with their target audiences. Noelle LoConte, M.D., an oncologist at the University of Wisconsin-Madison who studies alcohol and cancer risk, said that these findings confirm what doctors have long observed. Dr. LoConte said that she has direct conversations with her patients about drinking and other behaviors that could affect their treatment. And often she directs some of that discussion to family members and loved ones who are with the patient, essentially recruiting them to help manage the patient’s drinking. At the moment, however, proven ways to help people with cancer limit drinking during or after completing treatment are extremely limited, Dr. DuVall said.

Study Probes Awareness of Alcohol’s Link to Cancer

However, researchers have found no association between moderate consumption of red wine and the risk of developing prostate cancer (32) or colorectal cancer (33). There is a strong scientific consensus that alcohol drinking can cause several types of cancer (1, 2). In its Report on Carcinogens, the National Toxicology Program of the US Department of Health and Human Services lists consumption of alcoholic beverages as a known human carcinogen. According to the federal government’s Dietary Guidelines for Americans, 2020–2025, individuals who do not drink alcohol should not start drinking for any reason. The Dietary Guidelines also recommends that people who drink alcohol do so in moderation by limiting consumption to 2 drinks or less in a day for men and 1 drink or less in a day for women. Heavy alcohol drinking is defined as having 4 or more drinks on any day or 8 or more drinks per week for women and 5 or more drinks on any day or 15 or more drinks per week for men.

“We need to better understand these root causes and how best to address them,” she said. But results from a new study suggest that this information may not be reaching people who fall into either of these two categories. Community strategies can help communities create environments that reduce excessive alcohol use.

What is alcohol?

“The high prevalence of cancer survivors engaged in hazardous drinking highlights the need for immediate interventions,” they wrote. When you drink alcohol, your body breaks it down into a chemical called acetaldehyde. DNA is the cell’s “instruction manual” that controls a cell’s normal growth and function. When DNA is damaged, a cell can begin growing out of control and create a cancer tumor. If you’re taking prescription medicine, including cancer treatment, ask your doctor if it’s safe to drink alcohol. Because these alleles are allocated at birth and are independent of other lifestyle factors (such as smoking), they can be used as a proxy for alcohol intake, to assess how alcohol consumption affects disease risks.