You are currently viewing Expert analysis: Alcohol and cancer

Expert analysis: Alcohol and cancer

  • Post category:Blog

Guest blog by Dr Breeda Neville

Alcohol and cancer

Cancer is now the leading cause of death in Ireland. It is responsible for almost 1/3 of all deaths each year1. We have known for almost 40 years that alcohol causes cancer. It was first classified as a Group 1 carcinogen by the World Health Organization’s (WHO) International Agency for Research on Cancer (IARC) in 19882. This means that there is conclusive evidence that alcohol causes cancer and places it in the same category as tobacco, asbestos and radiation3.  

Is there a safe amount of alcohol to drink when it comes to cancer risk?

In 2023, the WHO declared that there is no safe level of alcohol consumption4. Drinking any beverage containing alcohol regardless of its type, price or quality increases your risk of developing cancer. Cancer risk begins with the first drop of alcohol that you drink and increases the more you drink. In the European Union (EU) in 2017 23,000 (almost 1 in 7) of all alcohol-attributable cancers were caused by ‘light’ and ‘moderate’ drinking (defined as less than 2 standard drinks per day)5. Almost half of these (~11,000) were female breast cancers. More than a third of the cancer cases resulting from light to moderate drinking were associated with a light drinking level of less than 1 standard drink per day5.

What types of cancer does alcohol cause?

We know that alcohol causes at least 7 types of cancer: mouth, throat (pharynx), voice box (larynx), oesophageal, breast (female), liver, and bowel cancers6. Breast and bowel cancers are two of the most commonly diagnosed cancers in Ireland7. While mouth, throat, voice box, oesophageal and liver cancers are less common, they generally have poor prognoses and overall survival rates are lower than for many other cancers7.

It is estimated that in Ireland in 2020, approximately 1,000 cases of cancer were attributable to, or caused by, alcohol consumption8. This included approximately 260 breast cancers and 320 bowel cancers8.

How does alcohol cause cancer?

Alcohol increases cancer risk in a number of ways. When you drink alcohol, your body metabolises it or breaks it down, converting it from ethanol to a toxic chemical called acetaldehyde9. Acetaldehyde can damage the DNA (genetic material) in your cells and interferes with the body’s ability to repair DNA damage6. The metabolism of alcohol also generates reactive oxygen species (ROS), which are highly reactive molecules that can damage DNA, proteins, and cell membranes through a process called oxidative stress. This oxidative stress increases the risk of mutations that can lead to cancer6.

Alcohol also interferes with the body’s ability to absorb important nutrients which may protect you from cancer. For example, it impairs the body’s ability to absorb folate which is a vitamin that plays a key role in making new DNA and in repairing damaged DNA9. Alcohol can alter the levels of certain hormones. It can increase the level of oestrogen in the body, particularly in women, increasing the risk of breast cancer9.

Alcohol also makes it easier for other harmful chemicals which can cause cancer, such as those found in tobacco smoke, to enter cells, particularly those of the mouth, throat and oesophagus. It does this by increasing the permeability of cells, or making them leakier and by acting as a solvent dissolving these harmful chemicals and making them easier for cells to absorb6. People who use both tobacco and alcohol have a 5-fold increase of developing cancers of the mouth (oral cavity), throat (pharynx), voice box (larynx), and food pipe (oesophagus) compared to people who use either alone6. For heavy users of alcohol and tobacco the risk is up to 30 times higher6.

Alcohol is extremely high in calories. It contains 7 calories per gram. Only pure fat has more calories, at 9 calories per gram. Other ingredients such as sugar, wheat and barley also contribute to the calorie content of alcoholic drinks10. These extra calories can lead to weight gain and according to the World Cancer Research Fund (WCRF) living with overweight or obesity increases your risk of developing at least 13 types of cancer11.

The importance of raising awareness of the link between alcohol and cancer

Despite the significant cancer risk associated with alcohol consumption, public awareness remains alarmingly low. The 2022 National Survey on Cancer Awareness and Attitudes which was carried out by the Health Service Executive’s (HSE) National Cancer Control Programme found that only 42%, or less than half, of people living in Ireland spontaneously identified alcohol as a risk factor for cancer12. Among those who were aware of the link between alcohol and cancer, almost half (46%) incorrectly believed that alcohol can only cause cancer if you drink a large amount over a long period of time12.

Worryingly, more recent research carried out by the HSE found that levels of awareness have fallen further since the 2022 study with only 38%, or less than 4 in 10, people now being aware that drinking alcohol can cause cancer13. To put this in context, the same research showed that 76%, or more than 7 in 10, people are aware that smoking causes cancer13. This is in spite of the fact that alcohol and tobacco are both Group 1 carcinogens6.

The public has a right to know that drinking alcohol, even at low levels, increases your risk of developing cancer. It is vital that they are armed with this information so that they can make informed decisions about their health.

  • Dr Breeda Neville BSc LRCP & SI MB BCh NUI MSc MPH MICGP MFPHMI is Consultant in Public Health Medicine, HSE National Cancer Control Programme
  1. Central Statistics Office. Vital Statistics Yearly Summary 2024 [Internet]. Cork: CSO; 2025 [cited 2025 Jul 17]. Available from: https://www.cso.ie/en/releasesandpublications/ep/p-vsys/vitalstatisticsyearlysummary2024/
  2. International Agency for Research on Cancer. Alcohol drinking. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volume 44. Lyon: IARC; 1988. Available from: https://publications.iarc.fr/60
  3. International Agency for Research on Cancer. Agents Classified by the IARC Monographs, Volumes 1–139 [Internet]. Lyon: IARC; 2024 [cited 2025 Jul 17]. Available from: https://monographs.iarc.who.int/agents-classified-by-the-iarc/
  4. World Health Organization Regional Office for Europe. No level of alcohol consumption is safe for our health [Internet]. Copenhagen: WHO; 2023 Jan 4 [cited 2025 Jul 17]. Available from: https://www.who.int/europe/news/item/04-01-2023-no-level-of-alcohol-consumption-is-safe-for-our-health
  5. Scheidt-Nave C, Rehm J, Shield KD, Manthey J, Rylett M, Hasan OSM, et al. Contribution of alcohol consumption to cancer incidence in eight European countries. Lancet Oncol. 2021;22(7):1071–1080. doi:10.1016/S1470-2045(21)00279-5
  6. International Agency for Research on Cancer. IARC Monographs on the Evaluation of Carcinogenic Risks to Humans. Volume 100E: Personal Habits and Indoor Combustions [Internet]. Lyon: IARC; 2012 [cited 2025 Jul 17]. Available from: https://publications.iarc.fr/Book-And-Report-Series/Iarc-Monographs-On-The-Identification-Of-Carcinogenic-Hazards-To-Humans/Personal-Habits-And-Indoor-Combustions-2012
  7. National Cancer Registry Ireland. Cancer in Ireland 1994-2022: Annual Statistical Report 2024 [Internet]. Cork: NCRI; 2024 [cited 2025 Jul 17]. Available from: https://www.ncri.ie/en/reports-publications/reports/cancer-in-ireland-1994-2022-annual-statistical-report-of-the-national
  8. Rumgay H, Shield K, Charvat H, Ferrari P, Sornpaisarn B, Obot I, et al. Global burden of cancer in 2020 attributable to alcohol consumption: a population-based study. Lancet Oncol. 2021;22(8):1071-1080. doi:10.1016/S1470-2045(21)00279-5.
  9. National Cancer Institute. Alcohol and Cancer Risk Fact Sheet [Internet]. Bethesda: NCI; 2024 [cited 2025 Jul 17]. Available from: https://www.cancer.gov/about-cancer/causes-prevention/risk/alcohol/alcohol-fact-sheet
  10. World Cancer Research Fund International. Alcohol and Cancer Prevention [Internet]. London: WCRF International; [cited 2025 Jul 17]. Available from: https://www.wcrf.org/diet-activity-and-cancer/cancer-prevention-recommendations/alcohol/
  11. World Cancer Research Fund/American Institute for Cancer Research. Diet, Nutrition, Physical Activity and Cancer: a Global Perspective. Continuous Update Project Expert Report 2018 [Internet]. London: WCRF; 2018 [cited 2025 Jul 17]. Available from: https://www.wcrf.org/dietandcancer
  12. National Cancer Control Programme. National Survey on Cancer Awareness and Attitudes 2022 [Internet]. Dublin: Health Service Executive; 2022 [cited 2025 Jul 17]. Available from: https://www.hse.ie/eng/services/list/5/cancer/pubs/national-survey-on-cancer-awareness-and-attitudes-2022.pdf
  13. Health Service Executive. HSE aims to improve public knowledge that alcohol is a carcinogen that causes at least 7 types of cancer [Internet]. Dublin: HSE; 2025 Jul 8 [cited 2025 Jul 17]. Available from: https://about.hse.ie/news/hse-aims-to-improve-public-knowledge-that-alcohol-is-a-carcinogen-that-causes-at-least-7-types-of-cancer/

    facebookShare on Facebook
    TwitterPost on X