Recent studies have uncovered diet, fitness, and lifestyle habits that could help prevent breast cancer.

By Mirel Ketchiff
Photo: Shutterstock

There's good news: The mortality rate for breast cancer has fallen by 38 percent over the last two and a half decades, according to the American Cancer Society. This means that not only have diagnosis and treatment improved, but we're also learning more about controlling key risk factors. Here's the best, latest advice for protecting yourself.

1. HIIT it twice a week.

High-intensity workouts can cut your chances of breast cancer by up to 17 percent. "Vigorous exercise reduces body fat, which lowers estrogen levels and decreases the risk of developing an estrogen-sensitive cancer," says Carmen Calfa, M.D., a breast medical oncologist at the Sylvester Comprehensive Cancer Center at the University of Miami. "It also lowers the amount of insulin in the bloodstream-important because the hormone stimulates the survival and spread of tumor cells. And working out reduces inflammation and activates natural killer cells, two things that may protect against cancer. All it takes is 75 minutes a week of pushing yourself, Dr. Calfa says. (Try this 10-minute cardio HIIT workout.) You'll know you're in the right intensity zone if you can gasp out only a few words at a time. An alternative is 150 minutes of weekly moderate exercise.

2. Choose containers carefully.

Bisphenol A (BPA), a chemical used to make hard plastics like reusable water bottles and food containers, activates a molecule called HOTAIR, which has been linked to increased breast cancer risk, according to a study in the Journal of Steroid Biochemistry and Molecular Biology. BPA simulates the effects of the female sex hormone estrogen, which can fuel some types of breast cancer, says Subhrangsu Mandal, Ph.D., the study's author. And it's not just BPA: Bisphenol S, which is commonly used in BPA-free plastics, may also increase breast cancer risk. (That's why Kourtney Kardashian avoids plastic containers.) While the experts say there still isn't enough research to prove conclusively that BPA can lead to breast cancer, they say that it's smart to minimize your exposure to plastics as much as possible. One way to do that: Use stainless steel and glass bottles and food containers, Mandal advises.

3. Eat (the right) dairy.

Women who regularly consume yogurt have a 39 percent lower risk of breast cancer, according to new findings from Roswell Park Cancer Institute. (All the more reason to make one of these protein-packed yogurt bowls.) But those who eat more hard cheeses, including American and cheddar, have a 53 percent higher risk of breast cancer. "Yogurt might modify levels of gut bacteria that help protect against cancer development," says lead researcher Susan McCann, Ph.D., R.D.N. "Cheese, on the other hand, is high in fat, and some studies have found a connection between breast cancer and higher fat intake," she says. "Or perhaps women who eat more cheese have less healthy diets overall."

More research needs to be done before experts can make any blanket recommendations, though, says Jennifer Litton, M.D., an associate professor of breast medical oncology at the University of Texas MD Anderson Cancer Center. But it makes sense to eat yogurt and watch your cheese intake. In the study, having three or four servings of yogurt a week was linked to a drop in breast cancer risk, whereas eating more than that amount of cheese raised the odds. (Eating more fiber could help lower your breast cancer risk too.)

4. Say yes to soy.

There's been a lot of confusion about soy, and no wonder: Some studies have shown that the isoflavones it contains can increase breast cancer risk; others found that soy has no effect and may even decrease your odds of developing breast cancer. Finally, though, there is some clarity. The majority of research now indicates that soy is OK. In fact, one recent Tufts University study of women with the disease showed that soy foods are actually associated with improved chances of survival. "Soy isoflavones have anticarcinogenic properties. They inhibit cell proliferation and reduce inflammation and oxidative stress," says Fang Fang Zhang, M.D., Ph.D., the study author. Go ahead and have soy milk, tofu, and edamame.

5. Ask your doc this important question.

The density of your breasts can directly affect your breast cancer risk, but unless you query your physician, you may never find out if this is an issue for you.

Younger women naturally have denser breasts because the tissue is made up of milk glands and ducts, which are necessary for breastfeeding, says Sagar Sardesai, M.D., a breast medical oncologist at the Ohio State University Comprehensive Cancer Center who has studied the subject. Typically "as women enter perimenopause, around age 40, the breasts should become fattier and less dense," he says. But 40 percent of women continue to have dense breasts. That's a concern, because those over age 45 whose breasts are more than 75 percent dense have an increased risk of breast cancer, Dr. Sardesai says. The tissue also makes mammograms difficult to read, and tumors can become obscured.

If you're 45 or older, ask your doctor how dense your breasts are, Dr. Sardesai says. Not all states require physicians to automatically disclose this information, so it's crucial to be proactive. If you find out that your breasts are more than 75 percent dense, you may want to consider alternate breast cancer screening methods, like a breast MRI or a 3-D mammogram, both of which are better at spotting tumors in dense breast tissue than regular mammograms.