You can't change your family history or when you started your period (studies indicate that a first menstrual period at age 12 or earlier increases breast-cancer risk). But there are things you can do to lower your breast-cancer risk.
1. Hold your weight steady
Study after study has found that women over 40 who weigh close to the same amount that they did in their 20s are less likely to get this disease. Ideally, you should gain no more than 10 percent of your body weight (so if you weighed 120 in college, you shouldn't gain more than 12 pounds over the subsequent decades).
It appears that excess body fat not only produces its own estrogen, it also allows the hormone, which increases the risk of breast cancer, to circulate more freely in the blood.
The age at which a woman becomes overweight affects risk, as does where the fat goes. For some reason, there is less breast cancer in younger obese white women who accumulate fat on their hips and thighs. But these same women experience a rebound effect at menopause, when risk rises. In pre-menopausal black women, body mass doesn't seem to decrease or increase risk.
2. Pump up your produce
Fruits and vegetables contain powerful antioxidants that help protect against all forms of cancer. Plus, they're low in calories, so loading up on them is an easy way to keep your weight in check. Studies have found that eating five servings of produce a day reduces the odds of a breast-cancer recurrence in women—young women in particular—especially when combined with daily exercise. Consuming more than that doesn't seem to have any additional preventive effect, according to a study published in the Journal of the American Medical Association. Your best bet: eating a wide variety of brightly colored produce.
3. Cut the fat
Studies on dietary fat have been conflicting and inconclusive, but most experts say it's still wise to steer clear of saturated fat as much as possible. Global research shows that breast cancer is less common in countries where the typical diet is low in total fat and saturated fat.
4. Get plenty of calcium and vitamin D
According to a 10-year Harvard study, premenopausal women who got 1,366 milligrams of calcium and 548 IU of vitamin D daily slashed their breast-cancer risk by a third, and their odds of getting invasive breast cancer by up to 69 percent. Eat calcium-rich foods like lowfat dairy products, canned salmon, almonds, fortified orange juice, and leafy greens, or take a 1,000- to 1,200-milligram calcium supplement. Although milk contains vitamin D, most yogurt and cheese do not. To get enough, you probably need a multivitamin, or if you're taking a calcium supplement, choose one that also contains 800 to 1,000 IU of vitamin D.
5. Sprinkle flaxseed on your cereal
Flaxseed is a good source of lignans, compounds that may play a role in preventing estrogen dependent cancers by inhibiting the development of tumors or slowing their rate of growth. Other sources of lignans include sunflower seeds, peanuts, cashews, rye bread, and strawberries.
6. Keep cookouts to a minimum
A recent study from the University of North Carolina found that postmenopausal women who had consumed a lot of barbecued and smoked red meat or chicken over their lifetimes had a greater risk of developing breast cancer than those who ate less. When you grill meat, the amino acids form compounds called heterocyclic amines, which are carcinogenic. They're especially concentrated in charred meat. Plus, when the fat drips on the heat source, it forms polycyclic aromatic hydrocarbons, another cancer-causing compound that binds to the meat.
If the barbecue grill is beckoning, protect yourself by marinating the meat first or cutting it into smaller chunks. Since these cook faster than larger pieces, the likelihood that carcinogenic chemicals will form is reduced.
7. Imbibe intelligently
Many studies have found a link between alcohol and breast cancer. The risk becomes significant at about two drinks a day. More than one daily drink increases your odds of developing breast cancer by 20 percent or more. In one Norwegian study, those who had two or more drinks a day during the previous five years had an 82 percent greater chance of developing breast cancer than those who didn't drink at all. Why? Alcohol may raise estrogen levels and interfere with the body's ability to use folic acid, a B vitamin that's been linked to cancer prevention.
One interesting caveat: Studies in the United States and Australia have found that women who drink but also get adequate amounts of folate don't have a higher risk of breast cancer. So if you tend to enjoy a glass or two of wine with your dinner on a regular basis, taking a multivitamin every day may be a wise idea. Even better, chow down on good sources of folate: spinach, romaine lettuce, broccoli, orange juice and green peas.
8. Fill up on fiber
A diet that's rich in fiber (30 or more grams a day) can halve the risk of breast cancer among premenopausal women. Fiber-rich foods contain antioxidants and phytochemicals that are thought to be protective.
The more exercise is studied, the clearer it becomes that physical activity protects women. Women who exercise on a regular basis have lower levels of insulin and insulin-like growth factor. These anabolic hormones promote cell division; when cells are constantly dividing and growing, there's a danger something will get pushed down the road to becoming cancer. High levels of insulin and insulin-like growth factor seem to act as fuel, possibly helping cancer take off. Exercise also helps by lowering the circulating level of estrogens.
Exercise helps prevent the pounds from piling on as you age. And that's a good thing for your breasts, since excess body fat increases the production of the hormone estrogen, which fuels many types of breast cancer. "Carrying extra weight is a huge risk factor for the disease after menopause, so it's important to learn to control it while you're young," says Marji McCullough, Sc.D., a nutritional epidemiologist at the American Cancer Society.
Now a new study has pinpointed the amount of exercise and the intensity level you need to reap breast health benefits. Researchers from the University of Wisconsin found that women who regularly worked up a sweat for at least six hours every week were 23 percent less likely to get breast cancer than those who didn't exercise. Vigorous exercise shortens the luteal phase of the menstrual cycle (the two or so weeks before you get your period), decreasing your exposure to estrogen.
10. Breastfeed your baby
You've probably heard that waiting until your 30s to give birth increases your risk of developing breast cancer. But new research from the University of Southern California shows that you may be able to counteract some of that effect by breastfeeding. The breasts may be particularly susceptible to the effects of cancer-causing substances in the environment, such as secondhand smoke or pesticides. Pregnancy seems to alter the breast cells so they're less vulnerable to these factors, and breastfeeding may change them even more.
11. Kick butts
While breast cancer is not considered a smoking-related disease per se, research has linked smoking in younger women to a greater risk of the disease. According to a study of more than 56,000 women published in the American Journal of Epidemiology, the breast cancer-promoting effects of cigarette smoking appear to be strongest in young women who have not yet had children. For example, women who had smoked a pack a day for 10 years before they gave birth for the first time were 78 percent more likely to develop breast cancer than women who never smoked. Need some stop-smoking support? Find a free quit plan, educational materials, and referrals to local resources at smokefree.gov.
12. Prevent it with a pill
For women with a greater-than-average risk of developing breast cancer--as a result of heredity, for example, or a suspicious biopsy--one of two estrogen inhibiting drug regimens may help keep the disease at bay. Researchers from the National Cancer Institute (NCI) revealed a nearly 50 percent reduction in occurrences of the illness in women who were given tamoxifen. Meanwhile, in another a large-scale NCI study, raloxifene, a pill formerly prescribed for osteoporosis, was found to work as well as tamoxifen, but with fewer risky side effects, like blood clots and uterine cancer.
Adapted in part from the National Cancer Institute (www.cancer.gov)