Almost a quarter of a million women will be diagnosed with breast cancer this year. And while early detection and more effective treatments have dramatically reduced the number of those who will die from the disease, researchers are still searching for ways to prevent it altogether.
"Right now there's no sure way to prevent breast cancer, but we know healthy habits significantly decrease your risk," says Debbie Saslow, Ph.D., director of breast and gynecologic cancer at the American Cancer Society.
Here, the latest cutting-edge thinking from researchers.
1. Get enough sleep
Postmenopausal women with breast cancer who routinely sleep less than six hours a night may be twice as likely to have more aggressive breast cancers compared with those who sleep longer hours, a new study has found.
"Cancer is a disease of mistakes in our DNA. Sufficient sleep is responsible for maintaining our circadian rhythm, which regulates our body's natural DNA repair. If that process is frequently disrupted, so is DNA correction," explains lead author Cheryl Thompson, Ph.D., of Case Western Reserve University in Cleveland.
If you have difficulty getting your six-plus hours, consider enrolling in an online sleep-improvement program, such as the Cleveland Clinic's Go! to Sleep plan, which combines cognitive behavioral therapy with tools including a daily sleep log and progress charts.
2. Lose weight
While the link between obesity and breast cancer is well-known, a recent study finds that just being overweight — but not obese — can also be detrimental for those who have already been diagnosed. The study of more than 4,000 women shows that being obese raised a woman's risk of recurrence by 30 percent and her risk of death by 50 percent, despite optimal treatments such as chemotherapy and hormonal therapy. And the risk of recurrence also increased with increasing BMI, even in women in the overweight range. The results pertained to women with hormone receptor–positive breast cancer, the most common type, which accounts for about 65 percent of cases.
"Breast cancer risk is linked to increased levels of estrogen, and fat tissue produces excess amounts of it," says lead author Joseph A. Sparano, M.D., of Montefiore Medical Center in the Bronx, New York. "Fat also raises insulin levels, which can stimulate tumor growth."
3. Eat more carrots
According to the Susan G. Komen foundation, a diet rich in fruits and vegetables reduces breast cancer risk. But foods with carotenoids appear to pack the most punch. Find them in orange and red produce such as carrots, squash, tomatoes, melon, and sweet potatoes.
A 2016 study that examined over 1500 breast cancer cases from almost a dozen countries found that high levels of beta-carotene and other carotenoids were associated with lower risk of estrogen receptor tumors.
This confirms earlier, more comprehensive research that reviewed results of over 3000 participants and found it lowered chances of getting all types of breast cancers.
4. Drink alcohol sparingly
That would be no more than one drink per day, according to the American Cancer Society guidelines on nutrition and physical activity for cancer prevention. One analysis of more than 40 studies found that just two drinks a day may raise your odds by 21 percent. If you already have the disease, one recent study showed that regular alcohol consumption (half a drink or more per day) increased recurrence in postmenopausal women by 19 percent.
"A possible reason is that alcohol consumption has been shown to elevate circulating estrogen levels in postmenopausal women," says lead author Marilyn Kwan, Ph.D., a research scientist at Kaiser Permanente Northern California in Oakland. "If you're a breast cancer survivor, talk to your doctor and consider limiting your intake to no more than a half drink per day or no more than three to four drinks per week," says Kwan.
5. Get up and go!
Walk. Garden. Vacuum. The latest research shows that any physical activity protects against breast cancer. And news that tops that: It's never too late to start. A new study finds that even women who didn't start exercising until after menopause showed diminished risk.
"This is particularly encouraging given the late age of onset for the disease," says study author Lauren McCullough, of the University of North Carolina. Women who exercised at any intensity for 10 to 19 hours per week reaped the greatest benefit; they had about a 30 percent reduced risk. That breaks down to about 90 minutes a day, which seems like a lot, until you realize that all activity counts.
"Just take note of how long it takes to perform the activities you're already doing every day, and build on that," McCullough says. "If you know you spend 15 minutes doing housework and another half hour in the garden, be sure to walk your dog for 45 minutes." Just don't use exercise as an excuse to gain weight. When researchers looked at the combined effects of physical activity, weight gain and body size, they found that active women who packed on pounds — particularly after menopause — had an increased risk of developing breast cancer. The bottom line: Weight gain can quash the beneficial effects of exercise, so keep your weight in check.
Holly St. Lifer is a freelance health reporter and writer.