A report from this week’s meeting of the American Association for Cancer Research questions that. Yesterday, Dr. Jasmine Lew presented the results of a study of 184,000 women in the US looking at the relationship between alcohol consumption and breast cancer. What they found may surprise you.
Dr. Lew’s group from the National Cancer Institute found that post-menopausal women who drank an average of 1-2 drinks a day were 32% more likely to develop hormone-sensitive breast cancer. Women who averaged 3 or more drinks a day were 51% more likely than nondrinkers to develop hormone-sensitive breast cancer.
So does that mean women should stop drinking? Not so fast…
An article written by Dr. James O’Keefe in the Journal of the American College of Cardiology last year reviewed the literature on health effects of alcohol. They reported on associations between alcohol consumption and a variety of conditions, including myocardial infarction (heart attack) in middle aged men, stroke, and the risk of type II diabetes. Their report shows that small amounts of daily alcohol consumption improves many health outcomes, while large intake makes them worse (see graph).
In a related study published in The American Journal of Clinical Nutrition in 2007, Dr. Pamela Mink and her colleagues reported results from the Iowa Women’s Health Study. Study participants were 34,489 postmenopausal women who were free of cardiovascular disease. They found an inverse relationship between dietary flavonoids and coronary heart disease, cardiovascular disease, and total mortality. Flavonoids are chemicals found in fruits, vegetables, and red wine that act as antioxidants. Because flavonoids in the diet can come from several sources, these doctors looked at the relationship between consumption of various specific foods and health outcomes, and found that red wine specifically was associated with decreased mortality from coronary heart disease and cardiovascular disease.
A major weakness of all of these studies is that they are population-based comparisons, meaning that they show a correlation between wine consumption and a particular disease process, but cannot prove a causal relationship. So we assume that because red wine is correlated with decreased heart disease, the red wine causes the drinker to have less heart disease. But maybe it’s not the wine, maybe it’s alcohol. Maybe it’s the cheese that gets eaten with the wine. Maybe it’s truffles in the sauce on the red meat that goes so well with the cabernet sauvignon. Studies like these just can’t tell.
So what’s a woman to do? There is no easy answer. Like all medical decisions, the reality is more complex than the headlines. Maybe if you have a strong family history of breast cancer but have no relatives with heart disease, abstinence from wine would be beneficial. Maybe if you had your first heart attack at 35 and don’t know anyone with breast cancer, a glass of red wine a day might not be a bad idea. For most women, however, the answer is unclear. So if you drink moderately, I’m not sure the report from the AACR meeting is a valid reason to stop. However, if breast cancer runs in your family, it certainly should prompt you to discuss your alcohol consumption with your doctor.