Does alcohol increase your risk of cancer, even with one drink a day?
Yes, even one drink a day increases the risk of certain cancers, particularly breast and colorectal cancer. There is no safe lower threshold; drinking less or stopping reduces your risk immediately.
Alcohol causes cancer, and that is not merely an association but an established causal relationship. Worldwide, approximately 4% of all cancers are directly attributed to alcohol. These include cancers of the mouth, throat, larynx, oesophagus, liver, colon, and breast.
In women, breast cancer stands out: more than half of all alcohol-caused tumours in women involve breast cancer. Alcohol raises oestrogen levels, which partly explains this risk. This is also why even low daily amounts can matter, because colorectal cancer and breast cancer are so common in the general population that even a small increase in risk is significant at a societal level.
How does it work? Your body converts alcohol into a toxic breakdown product that directly damages DNA, blocks DNA repair, and causes chromosomal abnormalities. On top of that, alcohol causes oxidative stress and suppresses your immune system. Some people, particularly those of East Asian descent, are genetically less able to break down that toxic breakdown product, which increases their cancer risk from alcohol even further.
Heavy drinking carries the highest risk, but there is no safe lower threshold. With one drink a day the risk is smaller than with heavy drinking, but it is not zero, particularly for breast and colorectal cancer. For lung, bladder, prostate, stomach, ovarian, and uterine cancer and melanoma, the available data do not show an increased risk.
Based on multiple large epidemiological studies and mechanistic studies (PMID 34579050, 15082451, 9751943, 7772271, 17718399, 36310188, 36258033, 11391063). The causal relationship for the cancer types mentioned has been scientifically established.