When a medical professional determines a breast is dense, it means that the breast has more breast tissue, glands and less fat. A high breast density is a risk factor for breast cancer and a lot of attention has been given to the topic recently. A study published in the 2011 "Breast Cancer Research and Treatment" journal followed infants for about 50 years and confirmed similar findings from previous studies, namely that breast density declines with age and increasing body mass index, and dense breasts occur more commonly pre-menopause than post-menopause. Although there is a strong link between breast density and genetics, some dietary factors might also play a role.
According to the American Cancer Society, ACS, there are no clear links between diet and breast cancer risk. Studies looking at both diet and supplements, such as vitamins, have been conflicting and have not yielded any consensus. The ACS recommends following a healthy diet to include five or more servings of fruits and vegetables, limiting red meats and substituting whole grains for refined grains.
Historical Cohort Study in Minnesota
According to results from a study of breast cancer families in Minnesota, there are a few dietary and supplement factors that have an association with breast density. Published in the 2000 issue of "Cancer Epidemiology, Biomarkers & Prevention," the study states that among premenopausal women, a decreased intake of saturated fat and increased intakes of vitamin C and E are associated with increased breast density. In postmenopausal women, there is a linear relationship between vitamin B-12 intake and breast density. Researchers call these associations in the Minnesota study small in magnitude but mention that they may have implications for breast cancer risk.
Alcohol and Hypoglycemia
There may not be a significant relationship between alcohol consumption and breast density after accounting for the known influencing variables, such as age, body composition, parity and menopausal status. Yet, in the aforementioned Minnesota historical cohort study, researchers found an inverse relationship between alcohol and breast density in both pre- and postmenopausal women. There was also a positive association between white wine and breast density and an inverse relationship between red wine and breast density.
There have been a number of inconclusive studies looking at the effect of isoflavones and breast density. One 2010 study in "Human Reproductive Update," however, was a meta-analysis of randomized controlled trials investigating isoflavone-rich foods or supplements versus a placebo, which found that intake does not affect breast density in postmenopausal women, but a small increase in density may be seen in premenopausal women. Isoflavones, such as in soy products and supplements, contain hormone-like compounds, which may have an impact on breast cancer risk.
The consensus among the medical community agrees with the ACS’ sentiments that there is no clear and consistent relationship between diet and breast density. The Breast and Cervical Cancer Control Program in Michigan claims that there is nothing women can do to decrease the density of their breasts. The Michigan government website goes on to say that breast density is genetic. A study in the "New England Journal of Medicine" in 2002, found that breast density is highly heritable. Among all twins studied, 63 percent of mammographic density was found to be accounted for by genetic factors.