Alcohol and breast cancer risk

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Alcohol and Breast Cancer Risk

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Drinking alcohol increases the risk of breast cancer in women and heavy drinking increases the risk in men.

The more alcohol a woman consumes the greater the risk, with no lower threshold.

Alcohol is metabolised into acetaldehyde, a cancer-causing compound. This occurs primarily in the liver but also in breast tissue.

Alcohol increases levels of circulating hormones including oestrogen, which increases breast cancer risk

Our tips to reduce your risk

Drink in moderation; as a minimum, do not exceed UK government guidelines of no more than 14 units of alcohol per week. The less you drink the less you are at risk

Know what 14 units of alcohol represents for the drinks you like to consume

Avoid binge drinking; to help with this, consider alternating between alcoholic and non-alcoholic drinks

Aim to have at least some alcohol-free days each week

Alcohol increases the risk of breast cancer

Alcohol increases the risk of breast cancer in women and heavy drinking may increase the risk in men (1). Drinking alcohol during pregnancy may increase the risk of breast cancer in daughters (2). In the UK it is estimated that 8% (around 4,400) of female breast cancer cases are linked to alcohol consumption (3, 4).

Does the type of alcoholic drink matter?

Any type of alcoholic drink increases the risk (5). All alcoholic drinks – be they beer, wine or spirits – contain ethanol, which is what causes harm. Different drinks contain different amounts of alcohol.

Type of drink	Alcohol by volume	Volume of drink	Alcohol (grams)	Alcohol (units)
Single shot of spirits	40%	25ml	8g	1 unit
Alcopop	4%	275ml	8.8g	1.1 units
Pint of beer	4%	568ml	18.4g	2.3 units
Small bottle of beer	5%	330ml	13.6g	1.7 units
Small glass of wine	12%	125ml	12g	1.5 units
Standard glass wine	13%	175ml	18.4g	2.3 units
Pint of cider	12%	125ml	12g	1.5 units

How much alcohol increases breast cancer risk?

The more women drink the more breast cancer risk increases (6). Even very light drinking (1 drink/week) increases the risk (7). Binge drinking (more than 6 units or 4 drinks in a short period) may be especially harmful (8). One study found pre-menopausal women who binge drink have twice the risk of breast cancer compared to non-binge drinkers (9). Some evidence suggests that drinking alcohol in adolescence and before a first pregnancy may increase risk more (10). For men, heavy drinking increases risk. Heavy drinking is twice the UK guidelines of 14 units/week which means 28 units or ~15 drinks/week). Light drinking may also increase male breast cancer, but more studies are needed.

Does alcohol increase the risk of all types of breast cancer?

Alcohol consumption is mainly associated with oestrogen receptor-positive (ER+) breast cancer.

Alcohol and breast density

Alcohol consumption increases breast density, which is strongly associated with increased breast cancer risk. It may also increase the risk of benign breast disease, which is itself a breast cancer risk factor (11, 12).

Alcohol and other risk factors

There may be a stronger association between alcohol and breast cancer risk among women who have hormone replacement therapy (HRT) (13). Risk is also increased for people who drink alcohol and smoke.

How does alcohol increase your risk of developing breast cancer?

Alcohol raises circulating oestrogen levels which increases breast cancer risk (14).
In the liver and breast tissue alcohol is broken down to acetaldehyde, a chemical compound that can cause cancer by damaging DNA.
Alcohol can cause weight gain, increasing the risk for post-menopausal women and men.
Alcohol may also affect the body’s immune system, how well it absorbs vitamins and nutrients; alcohol can also affect whether certain genes are switched on or off.

More research is needed into how alcohol increases breast cancer risk (15).

For more prevention tips visit our Prevention Hub

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References

1. Li, N. et al. (2019). Global burden of breast cancer and attributable risk factors in 195 countries and territories, from 1990 to 2017: results from the Global Burden of Disease Study 2017. Journal of Hematology & Oncology 12:140. https://pubmed.ncbi.nlm.nih.gov/31864424/.

2. Stevens, R. G. and Hilakivi-Clarke, L. (2001). Alcohol exposure in utero and breast cancer risk later in life. Alcohol and Alcoholism 36 (3): 276–277. https://academic.oup.com/alcalc/article/36/3/276/170149

3. Brown, K. F. et al. (2018). The fraction of cancer attributable to modifiable risk factors in England, Wales, Scotland, Northern Ireland, and the United Kingdom in 2015. British Journal of Cancer, 118(8), 1130. https://www.nature.com/articles/s41416-018-0029-6

4. This estimate is based on the number of cases of breast cancer in the UK which was 55,176 in 2017. Breast cancer statistics | Cancer Research UK (accessed 7.1.20).

5. Freudenheim, J. L. et al. (2020). Alcohol’s effects on breast cancer in women. Alcohol Research 40(2): 11. https://pubmed.ncbi.nlm.nih.gov/32582503/

6. Sun, Q. et al. (2020). Alcohol consumption by beverage type and risk of breast cancer: A dose-response meta-analysis of prospective cohort studies. Alcohol and Alcoholism 55(3): 246-253. https://pubmed.ncbi.nlm.nih.gov/32090238/

7. Shield, K. D. et al. (2016). Alcohol Use and Breast Cancer: A Critical Review. Alcoholism, Clinical and Experimental Research 40(6): 1166–1181. https://www.ncbi.nlm.nih.gov/pubmed/27130687

8. Sánchez-Bayona, R. et al. (2020). Binge Drinking and Risk of Breast Cancer: Results from the SUN (Seguimiento Universidad de Navarra) Project. Nutrients 12(3): 731. https://pubmed.ncbi.nlm.nih.gov/32164388/

9. Sánchez-Bayona, R. et al. (2020). ibid.

10. Freudenheim, J. L. et al. (2020). op cit

11. Voevodina, O. et al (2013). Association of Mediterranean diet, dietary supplements and alcohol consumption with breast density among women in South Germany: a cross-sectional study. BMC Public Health 13:203. https://pubmed.ncbi.nlm.nih.gov/23497280/

12. Freudenheim, J. L. et al. (2020). op cit

13. Freudenheim, J. L. et al. (2020). op cit

14. Lui et al. (2015). op cit.

15. World Cancer Research Fund/American Institute for Cancer Research. Continuous Update Project Expert Report 2018. Alcoholic drinks and the risk of cancer. op cit.

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