It is clear that heavy drinking is harmful to health. According to the Centers for Disease Control and Prevention (CDC), excessive alcohol use causes about 79,000 deaths every year in the United States.1 Excessive alcohol use is defined as more than one drink per day (on average) for women and more than two drinks per day (on average) for men. It can lead to many serious health problems including:1,2
However, we get mixed messages about the health effects of drinking low to moderate amounts of alcohol. Is having a glass of wine with dinner a few nights a week harmful or healthful? Are the health risks and benefits the same for everyone? Looking at the scientific evidence on drinking alcohol in moderation can help you weigh the risks and benefits for yourself.
Different types of alcoholic beverages contain different amounts of alcohol. One drink is defined as 0.6 ounces of alcohol, or:
Having even just a few alcoholic drinks each week appears to modestly increase the risk of breast cancer.3-5 And, the more a woman drinks, the higher her risk of breast cancer appears to be.3-6 A pooled analysis of data from 53 studies found for each alcoholic drink consumed per day, breast cancer risk increased by about seven percent.6 Women who had two to three alcoholic drinks per day had a 20 percent higher risk of breast cancer compared to non-drinkers.6
There are several ways that alcohol may play a role in breast cancer. Alcohol contains a lot of calories (and few nutrients). Among adults in the U.S., alcohol ranks fifth in top sources of calories.2 So, many of us are getting a lot of calories from alcohol and those extra calories can lead to excess weight and weight gain. The excess weight, in turn, can increase our risk of breast cancer.7-8 Heavier women tend to have higher blood levels of estrogen and higher levels of estrogen are linked to an increased risk of breast cancer.9
However, in studies that assessed the link between alcohol and breast cancer risk, alcohol was found to increase risk independent of (by means not related to) body weight.4,5,15-17 One reason may be that, alcohol affects the way the body processes estrogen, causing estrogen levels to rise.10-11 These different effects of alcohol on estrogen in the body explain how it increases breast cancer risk.
Some, but not all, studies show getting enough folate may help reduce the breast cancer risk related to alcohol.12-17 The nutrient folate is necessary for the body to copy and repair DNA. Drinking alcohol can reduce blood levels of folate. Low levels of folate may make it more likely that DNA is incorrectly copied when cells divide. Such errors can lead cells down a pathway to become cancerous.
Folate is part of a healthy diet and is found in foods such as oranges, orange juice and green leafy vegetables. And, most multivitamins and fortified breakfast cereals contain folic acid, the synthetic or man-made form of folate.
If you drink only in moderation (less than one drink a day for women), alcohol may have some health benefits, including:2,18-23
It is important to note that excessive alcohol drinking has no health benefits; only health risks. The health benefits of alcohol are limited to those who drink only in moderation.
However, you don’t have to drink alcohol to get these health benefits. Getting regular exercise and eating a healthy diet may help maintain cognitive function as well as lower your risk of heart disease and hypertension and even death.20,24-30
As we get older, heart health becomes especially important. This is true for everyone, including breast cancer survivors. We do not yet know if drinking alcohol in moderation has health benefits for breast cancer survivors. Study results are mixed. Some studies show no increased risk of breast cancer recurrence or breast cancer mortality, while others show a slight increase in risk.31-34
No one should ever drink alcohol in excess. Drinking more than one drink per day (for women) and more than two drinks per day (for men) has no health benefits and many serious health risks, including breast cancer. However, if you drink only low to moderate amounts of alcohol, there can be some health benefits, especially for your heart. If you currently drink alcohol only in moderation, weighing these risks and benefits can help you make informed choices.
Susan Hankinson, Professor of Medicine at Harvard Medical School offers this advice. “Moderate alcohol intake is one lifestyle factor well documented to have varying health effects in women – the increase in breast cancer risk and decrease in heart disease risk are both very well confirmed. Until we learn more about the mechanism, and possible ways to limit or eliminate the small increase in breast cancer risk with alcohol use, it will be important for individual women to weigh these risks and benefits.”
Susan G. Komen for the Cure® recommends that you:
1. Know your risk
2. Get screened
3. Know what is normal for you and see your health care provider right away if you notice any of these breast changes:
4. Make healthy lifestyle choices
1. Centers for Disease Control and Prevention (CDC). Fact sheets: Alcohol use and health. http://www.cdc.gov/alcohol/fact-sheets/alcohol-use.htm, 2011.
2. U.S. Department of Agriculture and U.S. Department of Health and Human Services. Dietary Guidelines for Americans, 2010. 7th Edition, Washington, DC: U.S. Government Printing Office. http://www.dietaryguidelines.gov, 2010.
3. Allen NE, Beral V, Casabonne D, et al. for the Million Women Study Collaborators. Moderate alcohol intake and cancer incidence in women. J Natl Cancer Inst. 101(5):296-305, 2009.
4. Lew JQ, Freedman ND, Leitzmann MF, et al. Alcohol and risk of breast cancer by histologic type and hormone receptor status in postmenopausal women: the NIH-AARP Diet and Health Study. Am J Epidemiol. 170(3):308-17, 2009.
5. Kotsopoulos J, Chen WY, Gates MA, Tworoger SS, Hankinson SE, Rosner BA. Risk factors for ductal and lobular breast cancer: results from the nurses' health study. Breast Cancer Res. 12(6):R106, 2010.
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8. Vrieling A, Buck K, Kaaks R, Chang-Claude J. Adult weight gain in relation to breast cancer risk by estrogen and progesterone receptor status: a meta-analysis. Breast Cancer Res Treat. 123(3):641-9, 2010.
9. The Endogenous Hormones and Breast Cancer Collaborative Group. Endogenous sex hormones and breast cancer in postmenopausal women: reanalysis of nine prospective studies. J Natl Cancer Inst. 94(8): 606-616, 2002.
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16 Tjønneland A, Christensen J, Olsen A, et al. Alcohol intake and breast cancer risk: the European Prospective Investigation into Cancer and Nutrition (EPIC). Cancer Causes Control. 18(4):361-73, 2007.
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20. Forman JP, Stampfer MJ, Curhan GC. Diet and lifestyle risk factors associated with incident hypertension in women. JAMA. 302(4):401-11, 2009.
21. Behrens G, Leitzmann MF, Sandin S, et al. The association between alcohol consumption and mortality: the Swedish women's lifestyle and health study. Eur J Epidemiol. 2011 Jan 26. [Epub ahead of print].
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28. Devore EE, Kang JH, Stampfer MJ, Grodstein F. Total antioxidant capacity of diet in relation to cognitive function and decline. Am J Clin Nutr. 92(5):1157-64, 2010.
29. Etgen T, Sander D, Huntgeburth U, Poppert H, Förstl H, Bickel H. Physical activity and incident cognitive impairment in elderly persons: the INVADE study. Arch Intern Med. 170(2):186-93, 2010.
30. Chang M, Jonsson PV, Snaedal J, et al. The effect of midlife physical activity on cognitive function among older adults: AGES--Reykjavik Study. J Gerontol A Biol Sci Med Sci. 65(12):1369-74, 2010.
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33. Hellmann SS, Thygesen LC, Tolstrup JS, Grønbaek M. Modifiable risk factors and survival in women diagnosed with primary breast cancer: results from a prospective cohort study. Eur J Cancer Prev. 19(5):366-73, 2010.
34. Kwan ML, Kushi LH, Weltzien E, et al. Alcohol consumption and breast cancer recurrence and survival among women with early-stage breast cancer: the life after cancer epidemiology study. J Clin Oncol. 28(29):4410-6, 2010.
"I'll do whatever it takes to keep fighting." - Kathleen