Alcohol
Also called: drinking, alcoholic drinks.
Last reviewed 2026-09-16. How this works.
Limiting or avoiding it Grade B
Good human evidence, with a limit worth knowing.
Alcohol is a known cause of seven cancers, and drinking less lowers the risk of some of them.
An established human carcinogen for seven cancers, and cutting down lowers the risk.
The claim
This one is not a claim made by advocates. It is the finding, and it is the strongest food entry in the chapter in the direction nobody wants to hear.
What it does
Alcohol is broken down to acetaldehyde, which damages DNA. The Working Group describes strong mechanistic evidence for reversible pathways involving acetaldehyde metabolism, genotoxicity, and immune and inflammatory processes. Reversible is the important word: the pathways recover.1
The evidence
Alcoholic beverages are classified as carcinogenic to humans, with sufficient evidence of causality for cancers of the oral cavity, pharynx, larynx, oesophagus, liver, colorectum and female breast.2
A later Working Group asked the more useful question, which is whether stopping helps. It concluded there is sufficient evidence that reduction or cessation reduces the incidence of cancers of the oral cavity and the oesophagus, limited evidence for larynx, colorectum and breast, and inadequate evidence for pharynx and liver.1
That graded answer is worth reading carefully. It does not say stopping undoes everything. It says the evidence is sufficient for two sites, limited for three and inadequate for two, which is a more honest shape than a single headline.1
The studies this rests on
-
IARC Working Group on reduction or cessation of alcohol consumption1
An agency evaluation of a literature, not a study, summarising observational studies, measured a clinical outcome.
sufficient evidence that reduction or cessation reduces incidence of oral cavity and oesophageal cancers.
What is absent
No randomised trial has assigned people to drink less and counted cancers. The evidence is observational and mechanistic, assessed by working groups, which for this question is as good as it is ever likely to get.
Scope: alcohol reduction with a cancer endpoint.
Established by trial scope, checked 2026-09-16. Result: both sources in this record are agency working-group assessments of observational and mechanistic evidence.12
What to ask
Given my diagnosis and my treatment, is there anything you would say about alcohol?
The dish-to-person gap
Alcohol is eaten as food rather than taken as a measured compound, and the register holds no human pharmacokinetic measurement for it.
When to call your team — no warning signs are recorded
If you have changed how you eat because of something you have read, or are thinking about it, the people treating you can only weigh that if they know about it. That is true when nothing has been written down here, and it is most true then.
The register records no warning signs for this entry. That is not a statement that nothing can go wrong.
Interactions
The register holds no measured interaction between alcohol and a cancer treatment class. Many cancer treatments do put a load on the liver, which is a reason to raise it with the team rather than a finding recorded here.
Nobody having looked is not the same as nothing being there. That is what this line says and all it says.
The whole interaction list, and how to turn it into a pharmacy review request.
Find a trial instead
This is an ordinary food rather than an intervention with recruiting trials attached.
References
IARC Handbooks of Cancer Prevention Volume 20A, Reduction or Cessation of Alcohol Consumption, 2024, summarised as a Special Report in the New England Journal of Medicine.
How this was reached: transcribed from chapter note, via docs/CHAPTER-NOTES.json, chapter 10 note 1.
International Agency for Research on Cancer classification of alcoholic beverages as carcinogenic to humans, Group 1.
No persistent identifier recorded.
How this was reached: transcribed from chapter note, via docs/CHAPTER-NOTES.json, chapter 10 note 8.