In general, women who maintain ideal body weight have a lower incidence of breast cancer. This effect probably operates through lowering the amount of estrogen that we know is produced by fatty tissue. Similarly, taking hormone replacement after menopause has been shown in a recent large clinical trial to increase a woman’s risk of developing breast cancer. The number of breast cancer events in this trial was small but the relationship is undeniable. Given this information, those women who already have significant risk factors for breast cancer may want to avoid even the small additional risk that hormone replacement therapy confers.
Dietary choices can also impact the incidence of cancer in general, though this relationship is less well understood. A diet rich in green leafy vegetables, which contain beta carotenes, seems to protect against a number of cancers. Similarly, soy based diets are associated with low rates of cancer overall, though there is some controversy regarding its use in preventing breast cancer as soy is a phytoestrogen and may hypothetically provide a growth factor for this type of cancer. Moderate alcohol consumption has been linked to an increased incidence of breast cancer, but this risk may be mitigated by ensuring an adequate intake of folate, a B vitamin found in whole grains. A number of other nutritional therapies aimed at cancer risk reduction are very provocative but rigorous scientific testing of these therapies has not yet been done. Fortunately, this is an area of emerging scientific interest and we will be hearing more about clinical trials involving natural therapies in the future.