"Exercise decreases the amount of fatty tissue in your breasts, which can increase breast density—but exercise is also associated with a decreased risk in breast cancer, so don’t quit your workout. Nearly half of all women have dense breasts, or breasts that have more connective tissue than fat. They’re more common in younger women and those taking hormones, like birth control or menopausal hormone therapy.
Dense tissue (which show up as white on a mammogram—same as cancer) can give you a slightly higher risk of breast cancer and also make it tricky for doctors to spot tumors. Unfortunately, a clinical breast exam (the screening tool for women under 40) won’t tell you if you have dense breasts. A mammogram, which we recommend after age 40 for women of average breast cancer risk, is the only way to find out.
If you're told you have dense breasts, sometimes a doctor will recommend a 3-D mammogram (which takes images of the breast at multiple angles) or a breast ultrasound for a more detailed view so we can better analyze the tissue."
-Therese Bevers, M.D., director of MD Anderson’s Cancer Prevention Center
"Vigorous activity like running, hiking uphill, or jumping rope reduces your risk of breast cancer that develops before menopause, while both moderate (walking briskly, gardening, a slow bike ride) and vigorous activity reduce your risk post-menopause.
We don’t know for certain how or why, but we have some ideas: for one, women who work out gain less weight as they age than those who don’t exercise, and weight gain is associated with an increased risk. We also know that exposure to estrogen over a woman’s lifetime increases her risk of breast cancer, and exercise has been shown to decrease estrogen levels. Working out also affects your insulin levels and the immune system, which can help lower your risk of the disease."
-Karen Basen-Engquist, Ph.D., director of the Center for Energy Balance in Cancer Prevention and Survivorship at The MD Anderson Cancer Center
"There aren’t any superhero foods that we know for sure can help fight existing breast cancer or prevent it from happening in the first place, but there’s some evidence that eating your veggies—particularly non-starchy ones like leafy greens and red or orange ones—might reduce your risk.
There is one thing we consume that definitely increases risk, and that’s alcohol. For every 10 grams of alcohol consumed per day, the risk of breast cancer before menopause increases by about five percent (your risk of post-menopausal breast cancer increases by nine percent). Ten grams of alcohol is equal to a 100 ml shot, or around 3.4 oz of wine. (That's much smaller than most restaurant serving sizes.)"
This interview has been edited and condensed for publication.