Ready to take action? We’ve sifted through the latest studies and talked to the leading experts so that you can know—and do—everything possible to prevent the disease.
How exercise impacts breast cancer.
Study after study has shown that exercise helps lessen the likelihood of breast cancer, but how much do you really need to lower your chances? Carlo La Vecchia, MD, of the University of Milan, who helped present the exercise-diet conclusion at the 2010 EBCC, recommends logging at least “three to four hours of moderate exercise” a week. That’s a great starting goal, says Kathleen Wesa, MD, of the Integrative Medicine Service at Memorial Sloan-Kettering Cancer Center in New York City, but “I suggest women aim for 30 to 60 minutes of moderate to vigorous activity five days per week.” Wesa defines 100 steps per minute while walking as moderate. “You want to increase your level of fitness, and if you’re sauntering, that’s not going to be effective.”
Indeed, going for a light walk or watching TV while leisurely pedaling the stationary bike may not be enough, according to a recent National Cancer Institute study of more than 110,000 postmenopausal women. Researchers tracked participants’ exercise habits for a decade to find that those who logged more than seven hours of moderate to vigorous exercise a week for the past 10 years were 16 percent less likely to be diagnosed with breast cancer than those who remained inactive or exercised less or not as vigorously.
If the word “vigorous” triggers a guttural reaction, John Potter, MD, professor of epidemiology at the University of Washington and senior advisor of Seattle’s Fred Hutchinson Cancer Research Center, says to start slowly. “Any activity is better than nothing,” says Potter, who recommends exercise-phobes begin by walking 30 minutes four days a week, then work up slowly to daily, regular intense activity lasting up to an hour. “Vigorous exercise—getting sweaty and breathing hard—is better than low-intensity exercise, but any exercise is better than setting the bar too high so that it causes failure, too much pain, or an injury,” Potter concludes.
Eat fruits and vegetables—but some more than others.
When asked which foods he deemed best for lowering the likelihood of breast cancer by that whopping one-third, La Vecchia responds that “a diet rich in fruits and vegetables, and thereby in micronutrients and food components like flavonoids, appears to be most favorable.” This—as well as the long-standing recommendation from the American Cancer Institute to eat five or more servings of fruits and vegetables daily to prevent cancer—contradicts a much-publicized 2010 study from Mount Sinai School of Medicine’s Tisch Cancer Institute that found only a weak association between high produce intake and reduced cancer risk.
So which is it? Does food matter? “Not all fruits and vegetables are created equal, and not all people respond the same way to their presence in the diet,” says John Milner, PhD, chief of the nutritional science research group for the National Cancer Institute. “But fruits and vegetables likely play an important role in breast cancer risk reduction, as well as in the risk reduction of many other diseases.” Milner says berries, cruciferous vegetables like broccoli, and bulb crops, including onions, leeks, and garlic, have the strongest data from the most studies to suggest that increased intake can help lower your likelihood. Additionally, he says, women should consider upping their intake of pomegranates: A new study from Israeli researchers discovered that pomegranate seed oil causes breast cancer cells to self-destruct in laboratory experiments. Milner and other experts believe the fruit, when consumed frequently and over time—within an appropriate caloric intake—may also help decrease a woman’s chance of getting breast cancer.
Can a Mediterranean diet fight breast cancer?
Boosting your dietary intake of fruits and vegetables is critical regardless of your everyday nutritional approach, but if you really want to do everything you can to guard against breast cancer, adopt the Mediterranean diet, say top experts. A study of more than 14,000 Greek women published in the American Journal of Clinical Nutrition in July found that postmenopausal women who adhered to a Mediterranean-style plan—or who ate primarily whole grains, nuts, legumes, olive oil, fish, and up to 10 servings daily of fruits and vegetables—were 22 percent less likely to develop breast cancer than those who didn’t follow or only partially complied to the diet.
According to Roger Clemens, PhD, spokesman for the American Society of Nutrition, which publishes the journal in which the study appeared, the Mediterranean diet helps reduce cancer risk because it combines the right types of cancer-blocking foods into one healthy approach. “Consuming no one food or food group alone prevents breast cancer,” Clemens explains. “But eating the right blend of foods really reduces your risk of the disease.”
The caveat, say researchers, is to ensure that you do really adhere to the diet. “I recommend people eat three to five servings of fruits and three to five servings of vegetables daily, along with plenty of lean protein, extra-virgin olive oil, and unprocessed whole grains,” Wesa says.
Although wine, particularly red, has received much acclaim as an important age-reversing, disease-fighting component of the Mediterranean diet, most experts advise women at risk for breast cancer to drink no more than one five-ounce glass of the heart-healthy beverage a day. “Alcohol intake is a nuanced message,” says Michelle Holmes, MD, associate professor of epidemiology at the Harvard School of Public Health. “We know that drinking alcohol increases a woman’s risk of getting and dying from breast cancer, but moderate alcohol intake can also decrease her risk of getting and dying from heart disease. The balancing point—where the benefit of decreasing heart disease is more than the downside of increasing breast cancer—occurs among women who consume a half-glass or full glass of alcohol per day.”
Know your BMI —then change it.
Exercising more and opting for fewer processed grains and sugars and more fruits and vegetables will help you maintain, if not lose, weight. But for overweight and obese women, lowering overall body mass index, or BMI—the standard measure of body fat based on height and weight—should be priority No. 1. “Being overweight or obese is a major risk factor not only for breast cancer, but for many diseases,” Wesa says. Why? The reason is threefold, Potter explains. First, obesity increases the body’s insulin levels and insulin-like growth factors (IGFs) that have a growth-promoting effect on cells—especially, perhaps on malignant and pre-malignant cells. But being overweight also boosts the body’s estrogen levels, which research shows stimulates cell growth of estrogen-sensitive breast cancer—the most common type of breast cancer among Western women. Finally, Potter says, recent studies have also proven conclusively that overweight and obese women have higher levels of inflammation, which provide an unsafe pro-cancer environment for the development of the disease in the breasts, lungs, and other organs.
According to the National Cancer Institute, any BMI over 25 increases a woman’s likelihood of incurring breast cancer significantly, while a BMI of more than 30, which is considered obese, pushes a woman’s risk of developing the disease to more than 60 percent, reports a 2006 British study of more than 6,000 women. To lower your risk, start by learning your BMI: Visit the National Institutes of Health’s website for a free online BMI Calculator. If your number is over 25, begin exercising and reducing your daily caloric intake immediately, while choosing fresh produce, lean protein, and healthy fats over processed carbohydrates, fatty meats, and sugary foods. “I won’t quibble with someone saying, ‘I’m big boned or muscular and can thereby weigh more and still be healthy,’” says Christine D. Berg, MD, chief of the early detection research group of the National Cancer Institute. The take-home? Stop making excuses and start taking steps that can help prevent your risk of breast cancer—it may just save your life.
Find toxins in your home—and eliminate them.
Diet and exercise aren’t the only factors that can increase your breast cancer risk. More and more studies examining the effects of environmental toxins suggest that everyday chemicals found in our homes and water supply may be responsible for rising rates of the disease, the incidence of which has increased by 30 percent over the past 25 years, says the American Cancer Society. Here are three ways to reduce your risk, according to Ruthann Rudel, director of research for the Silent Spring Institute, the leading nonprofit research group focused on finding links between the environment and breast cancer.
Throw out your chemical cleaners.
A 2010 study by Rudel and her colleagues published in Environmental Health found that frequent use of common chemical cleaners may increase a woman’s risk of breast cancer by as much as 50 percent. According to Rudel, many commercial cleaners contain hormone-disrupting chemicals that could effectively increase estrogen levels, shown to interfere with cell growth and development. Since scientists aren’t sure exactly which chemicals are hormonally active—and the chemicals aren’t tested before being added to commercial cleaners—Rudel says it’s best to limit use of commercial products, choosing toxin-free, simple alternatives like vinegar whenever possible.
Increase indoor air quality by decreasing consumer products. In a study published in Environmental Science & Technology in August, Silent Spring researchers discovered that concentrations of endocrine-disrupting chemicals (EDCs) are higher in our homes than in outdoor air. “Based on laboratory experiments, EDCs in high concentrations increase the risk of breast cancer,” Rudel says. EDCs, found in commercial furniture, carpets, detergents, clothing, electronics, and building products, are difficult to avoid altogether, but Rudel says you can reduce your exposure simply by buying fewer commercially produced goods (do you really need that plastic bowl or another table for the foyer?). When remodeling or moving, she adds, opt for chemical-free rugs (avoid additives like “stain-resistant”) and choose woods instead of vinyls and plastics. Also, allow new products, including newly dry-cleaned clothes, to off-gas outside before bringing them inside.
Investigate the water supply. Ongoing research from the Silent Spring Institute continues to show that our groundwater supplies can be contaminated with high levels of endogenous hormones, chemical cleaners, and certain pharmaceutical drugs—all of which can increase your chances of incurring breast cancer. Rudel suggests women contact their local water department to find out about their water source—you can also look up your water supply online by visiting the Environmental Working Group’s Tap Water Database (ewg.org/tap-water/whats-in-your-water). Or you can buy a home-testing kit or send your water to a state-certified lab to be tested (find one by calling the Safe Drinking Water Hotline at 800.426.4791 or visiting epa.gov/safewater/labs).
If your water’s chlorinated or shows concentrations of nitrate (a chemical in fertilizer and septic-tank runoff) over 1 mg/L, invest in a filter, says Rudel, adding that you must change the filter when recommended to avoid oversaturation and the release of collected toxins back into the water. Finally, don’t even think about buying bottled water unless you choose a supplier that doesn’t use endocrine-disrupting bisphenol-A in its plastic bottles or jugs.