Why Alcohol Is A Bigger Cancer Risk Than Most Of Us Realize

Alcohol consumption plays a significant role in many different cultures and societies around the world. It's often associated with celebrations, happy occasions, socializing, and weekend relaxation. In 2012, a World Health Organization (WHO) survey estimated that 38.1% of people globally aged 15 years or older drink regularly, and the average consumption of pure alcohol among drinkers was 38.6 g per day (that's equivalent to 3.2 drinks).¹

In the US, a 2018 national health survey by the Centers for Disease Control and Prevention found that 66.3% of adults 18 years old and older consumed alcohol in the past year. Within the total sample, 45.7% were light weekly drinkers (3 or fewer drinks a week), 15.5% were moderate weekly drinkers (4-14 drinks weekly for men and 4-7 drinks weekly for women), and 5.1% were heavy weekly drinkers (14 or more drinks weekly for men and more than 7 weekly drinks for women).²

It's clear that most people wouldn't think twice about having several alcoholic beverages each week, as it falls within the range of what most public health bodies recommend as "drinking in moderation." Proponents of drinking will even reason that it's good for well-being, citing scientific studies that show a drink or two a day may benefit heart health and reduce risks of premature death.³ ⁴ ⁵ ⁶

However, a growing amount of recent research suggests that alcohol might be more harmful than we thought, especially in terms of its links to cancer risk. 

Even light to moderate drinking is associated with increased cancer risk

According to The International Agency for Research on Cancer (IARC), which was set up by the WHO, it’s estimated that a minimum of 1 in 25 cases of global cancer is a result of alcohol consumption. In 2020 alone, over 740,000 new cancer cases worldwide were linked to alcohol use, with esophageal and colorectal cancers being the most common types.⁷ ⁸

In the US, a survey published in Cancer Epidemiology found that alcohol consumption was linked to over 75,000 new cancer cases and almost 19,000 deaths each year between 2013-2016.⁹ Another 2013 meta-analysis of US data suggests that 3.2-3.7% of cancer deaths in the US are alcohol-related.¹⁰

What's worrying is that even a seemingly innocuous drink or two a day (or what many consider to be “in moderation”) can still increase your chances of developing cancer. 

For reference, The National Institute on Alcohol Abuse and Alcoholism defines a standard alcoholic drink as any drink that contains 14 grams (0.6 ounces) of pure alcohol. This can generally be found in 12 ounces of beer, 5 ounces of wine, or 8-9 ounces of malt liquor.¹¹

The 2013 US analysis found that drinking 20 grams of alcohol a day (the equivalent of about 1.5 drinks) accounted for 26% to 35% of cancer deaths caused by alcohol drinking. 

The more recent global IARC study in 2020 found that consuming more than 60 g of alcohol daily accounted for 46.7% of cancer cases (346,400) attributed to alcohol consumption. Those that drank between 20 to 60 g of alcohol per day accounted for 39.4% of cases (291,800).

Surprisingly, consuming a "moderate" 20 g of alcohol a day still contributed to 13.9% of these cancer cases (103,100). 

The link between alcohol and different types of cancer

Alcohol use also has particularly strong links with certain types of cancer.¹² ¹³ ¹⁰ ¹⁴ ¹⁵ ¹⁶ ¹⁷ ¹⁸

Head and neck cancers

Alcohol consumption has been found to be responsible for 49.8% of oral cavity or pharyngeal (throat) cancers along with 30.1% of laryngeal (voice box) cancers. 

The risk of developing certain head and neck cancers is 1.4-1.8 times higher for moderate drinkers than non-drinkers, and this risk increases to 2.6-5 times more for heavy drinkers. 

Upper airway and esophageal cancer deaths related to alcohol use are also more common among men (53% to 71%).

Esophageal cancer

Any amount of drinking has been linked to an increased risk of developing esophageal squamous cell carcinoma (a type of esophageal cancer). Light drinkers have 1.3 times the risk of having this cancer, heavy drinking is linked to almost 5 times the risk. 

Liver cancer

Heavy alcohol use has been associated with liver damage and liver cancer. However, even relatively smaller amounts (25 g of alcohol per day) have been associated with an increased risk of liver cancer.

Breast cancer

Alcohol-attributable breast cancer is a big concern for females. Between 56% and 66% of cancer deaths caused by alcohol use in U.S. females come from breast cancer. Every added 10 g of alcohol consumed also increases breast cancer risk by 7%. 

Colon and rectal cancer

Heavy drinking (more than 50 g of alcohol a day) is linked to a 1.44-fold increase in colorectal cancer risk compared to no or occasional alcohol consumption. But even a 15 g (about 1 standard drink) increase in alcohol intake daily is enough to impact your risk too. 

There is also growing evidence that alcohol use can cause other cancers like melanoma, prostate, and pancreatic cancer as well. 

Studies have also demonstrated that it may increase one's risk of getting second primary cancer. This is when a person develops another cancer unrelated to their previous cancer. One such meta-analysis looked at patients with cancer of the upper aerodigestive tract (UADT) — which includes the lips, mouth, tongue, and throat.

Researchers found that every 10 g of alcohol consumed daily before the initial UADT cancer diagnosis increases the risk of a second primary UADT cancer by 1.09 times.

How does alcohol compare to cigarettes in terms of cancer risk?

To put alcohol's cancer risk into perspective, a group of researchers conducted an analysis in 2019 comparing it to cigarettes — a carcinogen that the public seems to have more awareness about. They found that moderate drinking (about a bottle of wine a week) has the same cancer risk as smoking 10 cigarettes a week for females and five cigarettes for males. 

Their calculations also revealed that if 1,000 non-smoking women and 1,000 non-smoking men were to each drink a bottle of wine each week, an extra 14 women and 10 men within the group would develop cancer.  

The findings highlight that alcohol is a public health issue that's just as important as smoking and the cancer risks of alcohol need to be given more attention.¹⁹ ²⁰

There's no real benefit to drinking alcohol

What about those frequently touted studies suggesting that drinking (particularly red wine) is beneficial to heart health? More specifically, it's been suggested that the plant compound called resveratrol in red wine is what causes it to have antioxidant and anti-inflammatory properties.  

It turns out that to even get a therapeutic level of 1g of resveratrol a day, one would have to consume over 500 liters of red wine.²¹

Furthermore, there are too many other factors at play that could influence the results linking red wine with good health. 

As Dr. Robert Kloner, Director of Cardiovascular Research at Huntington Medical Research Institutes and Professor of Medicine at the University of Southern California has said in an interview with the American Heart Association, "It might be that wine drinkers are more likely to have a healthier lifestyle and a healthier diet such as the Mediterranean diet, which is known to be cardioprotective."²² ²³

A 2016 meta-analysis also revealed that many of the 87 previous studies looking at the relationship between alcohol and life expectancy had flaws in the research design. After adjusting for these design factors, the researchers concluded that light drinking offers no health benefits compared to total abstinence or occasional drinking.²⁴

The bottom line is that the dangers of alcohol far outweigh any potential benefits. If you're keen on getting more resveratrol from your diet, you can explore alternative sources like peanuts or dark chocolate.

How does alcohol raise cancer risk?

Researchers are still investigating how exactly alcohol use causes cancer, but here are some of the most likely biological processes:

Ethanol is the type of alcohol present in alcoholic drinks. When consumed, this chemical gets broken down by the liver into acetaldehyde which is carcinogenic (cancer-causing). It causes damage to DNA and prevents it from being repaired. As DNA is the biological “instruction manual” for normal cell function, its damage causes the abnormal division of cells —  which is the hallmark of cancer.²⁵ ²⁶

Alcohol can also indirectly influence abnormal cell division by making hormone levels imbalanced. One theory is that alcohol increases estrogen levels which causes cells to divide more rapidly. The more that cells divide, the more chances there are for the process to be disrupted and result in cancer.²⁷

Consuming alcohol can also lead to the production of reactive oxygen species — an unstable compound that damages DNA, protein, and fats through oxidation. It may also impair the body's ability to take up certain nutrients (like vitamins A, C, D, and E) and this has also been linked to increased cancer risk.¹³

Does cancer risk decrease when a person stops drinking alcohol?

The good news is that alcohol-related cancer risk does decrease after a person stops drinking — but this risk reduction does take some time.

Many of the studies that have looked at the effect of quitting alcohol on cancer risk have specifically addressed head and neck cancers. One meta-analysis found that drinking cessation is related to a 2% average reduction each year in the risk of developing laryngeal (voice box) and pharyngeal (throat) cancers. Stopping alcohol consumption over 5 years is linked to a 15% reduction in the risk of developing laryngeal and pharyngeal cancers due to alcohol.

However, bringing a regular alcohol drinker's risk of laryngeal and pharyngeal cancers down to the level of a non-drinker takes a considerable amount of time. The researchers estimate that it would take 36 years for laryngeal cancer and 39 years for pharyngeal cancer.²⁸

Public health needs to redefine "drinking in moderation"

These results highlight how limiting alcohol consumption should be done as soon as possible to reduce cancer risk. Some experts have even suggested that current definitions of "drinking in moderation" be re-evaluated with the current evidence that even light to moderate consumption can add to cancer risk.

For example, the UK government made significant changes to the recommended drinking limits in 2016 and clearly explained that there are no "safe" limits to alcohol consumption when it comes to cancer — every drink adds risk. It now has one of the lowest limits in the world at 14 units per week for both males and females (1 unit is 8 g of alcohol or half a small glass of wine).²⁹ ³⁰ ³¹ ³²

Increased awareness needed about the link between alcohol and cancer

Public health institutions also urgently need to change the narrative around alcohol limits, because most of the general public isn't even aware of alcohol's cancer risk.

In a recent survey, researchers found that of 3,900 US adults sampled, only about a third were aware that alcohol can increase the risk of developing cancer. When they were questioned about specific drinks, only 20% said wine can increase cancer risk and it was 25% for beer.³³

Similarly, only 10% of people in a UK survey said that cancer is a possible effect of consuming too much alcohol.³⁴

In 2017, researchers identified the alcohol industry as a culprit in perpetuating the public’s lack of awareness about the alcohol-cancer link. They performed qualitative analyses of a variety of educational content from responsible drinking organizations set up by the alcohol industry. The results demonstrated that there was frequent misrepresentation and downplaying of the health effects of alcohol consumption — especially when it comes to light drinking.³⁵ ³⁶

Public health bodies need to do more to address this lack of awareness in communities about the carcinogenic effects of alcohol. Preliminary surveys have already found that such knowledge could empower consumers to make wiser choices about alcohol use. They are more likely to support government use of warning labels on alcohol products and pricing policies.

One Canadian survey also found that 69% of respondents said they would drink less if they knew alcohol can increase cancer risk.³⁷ ³⁸

In light of the most recent research, public perception that there is a “safe” level of drinking needs to change — every alcoholic drink consumed carries a cancer risk. This is why the American Institute for Cancer Research states that drinking no alcohol (abstaining) is the best strategy for preventing cancer. But if you do drink, the institute recommends limits of 2 drinks a day for men and 1 drink a day for women.

Sources:

1. Cancer incidence and mortality attributable to alcohol consumption (2016)

2. Heavy drinking among U.S. adults, 2018 | Centers for Disease Control and Prevention

3. Moderate alcohol consumption and coronary heart disease: a review (2001)

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5. Social and cultural aspects of drinking | Social Issues Research Centre

6. Dietary guidelines for alcohol | Centers for Disease Control and Prevention

7. Data sources & methods | International Agency for Research on Cancer

8. Global burden of cancer in 2020 attributable to alcohol consumption: a population-based study (2021)

9. Proportion of cancer cases and deaths attributable to alcohol consumption by US state, 2013-2016 (2021)

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11. What Is a standard drink? | NIH: National Institute on Alcohol Abuse and Alcoholism

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13. Alcohol and cancer risk | NIH: National Cancer Institute

14. Alcohol, tobacco and breast cancer – collaborative reanalysis of individual data from 53 epidemiological studies, including 58 515 women with breast cancer and 95 067 women without the disease (2002)

15. The link between alcohol and bowel cancer | Alcohol and Drug Foundation

16. Lifetime and baseline alcohol intake and risk of colon and rectal cancers in the European Prospective Investigation into Cancer and Nutrition (EPIC) (2007)

17. Alcohol consumption, drinking patterns and cancer incidence in an Australian cohort of 226,162 participants aged 45 years and over (2020)

18. Alcohol drinking and second primary cancer risk in patients with upper aerodigestive tract cancers: A systematic review and meta-analysis of observational studies (2013)

19. A comparison of gender-linked population cancer risks between alcohol and tobacco: how many cigarettes are there in a bottle of wine? (2019)

20. When it comes to cancer, how does alcohol compare to smoking? | The Institute of Cancer Research

21. Resveratrol: How much wine do you have to drink to stay healthy? (2016)

22. Drinking red wine for heart health? Read this before you toast | Heart Attack and Stroke Symptoms

23. Every alcoholic drink increases your risk of cancer | Alcohol and Drug Foundation

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25. 3 Weird things about acetaldehyde | Centers for Disease Control and Prevention

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29. Alcohol limits cut to reduce health risks | BBC

30. How do the UK's new alcohol guidelines compare with the rest of the world's? | The Guardian

31. What if alcohol were harmful, even in moderation? (2017)

32. Chapter 12: Alcohol | GOV.UK

33. Most Americans still unaware that alcohol is a cause of cancer | American Institute for Cancer Research

34. An investigation of public knowledge of the link between alcohol and cancer | Cancer Research UK

35. Drinks industry downplaying alcohol-cancer link – report | The Guardian

36. How alcohol industry organisations mislead the public about alcohol and cancer (2017)

37. Awareness of alcohol as a carcinogen and support for alcohol control policies (2022)

38. Improving knowledge that alcohol can cause cancer is associated with consumer support for alcohol policies: Findings from a real-world alcohol labelling study (2020)

Dawn Teh is a health writer and former psychologist who enjoys exploring topics about the mind, body, and understanding what helps humans thrive.