A 2011 study published in the Journal of the American Medical Association reveals that even moderate alcohol consumption can lead to an increased risk of breast cancer.
With so much information out there about the cardiovascular benefits of drinking moderate amounts of red wine, it’s easy to see how this might bring confusion to the table.
To help clarify what this study really reveals, let’s break it down:
The Nurse’s Health Study
The study is based on information collected from 105,986 women as part of the Nurse’s Health Study, a cohort of female registered nurses aged 30 to 55 years who biennially respond to questionnaires including items on risk factors for cancer and cardiovascular disease.
Researchers from Harvard Medical School affiliated with Brigham and Women’s Hospital followed up on the data, beginning with an early adult alcohol assessment and eight subsequent alcohol assessments to evaluate the association of breast cancer with alcohol consumption. The study is likely the longest of its kind, covering a period of nearly 30 years from 1980 to 2008.
During the follow-up period, 7,690 participants were diagnosed with invasive breast cancer.
Based on the analysis, when compared with their non-drinking counterparts, women who reported drinking 3-5 servings of alcohol per week were 15% more likely to develop breast cancer. That number shot up to 28% in those who consumed 10-14 servings of alcohol per week, with an astonishing 51% increased risk in women drinking 15 or more servings per week.
The study stresses that the results do not apply to women who “binged” occasionally (consumed four or more drinks at one time) but rarely drank otherwise. Instead, it identifies cumulative average alcohol consumption over long periods of time as the most relevant measure of any increase in breast cancer risk.
One probable mechanism identified for this alcohol-breast cancer connection involves alcohol’s effects on circulating estrogen levels, which have been shown in other large studies to have a stronger association with certain types of breast cancers. Other studies also support a positive association between alcohol consumption and plasma sex hormone levels, which can affect estrogen-related breast cancer categories.
Ultimately, lead author Dr. Wendy Chen and her fellow researchers conclude that while there is “an increased risk [of breast cancer] at low levels of [alcohol] use,” the risk is actually “quite small.” In addition, they state that their results show “the importance of considering lifetime exposure when evaluating the effect of alcohol, and probably other dietary factors, on the carcinogenesis process.”
This research certainly is compelling because the women were followed for a long period of time. Nevertheless, other research has indicated the health benefits of moderate drinking which include a reduction in the risk of coronary heart disease by 30-35% and a reduction in the risk of stroke and dementia. Moderate drinking increases HDL or “good” cholesterol and prevents platelets from sticking together which reduces blood clots and lowers the risk of congestive heart failure.
The study shows an association between alcohol and breast cancer, but it is not proof that alcohol consumption causes cancer. It is likely just one of many contributing factors that affect the development of cancer.
The Bottom Line
As with most things in life, moderation is key. The difficulty with alcohol lies in defining what “moderation” means for you. It’s surprising how little “one serving” of alcohol really is: 1.5 oz. of spirits; 12 oz. of beer; or 5 oz. of wine.
At the end of the day, the best way to improve your health and your quality of life is to focus on making those dietary & lifestyle changes that have proven health benefits. This includes moving towards a mostly plant-based diet that is rich in nutrients like Omega-3s and fiber, with reasonable indulgences mixed in. Red wine anyone?