There are many misconceptions about what factors raise the risk of breast cancer. Although wearing an underwire bra or using antiperspirant has not been proved to cause breast cancer, day-to-day choices can play a significant role in who develops the disease. Here are some positive steps you can take in the battle to prevent breast cancer.

Eat Well

Consuming a balanced diet is essential for good health, but knowing what constitutes “good eating habits” has become increasingly confusing in a world filled with fad diets. Furthermore, the research on diet and breast cancer risk has yet to establish any definite cause-and-effect relationships. Nonetheless, here are a couple of ways to improve your eating habits and potentially lower your risk.

Limit Red and Processed Meat

A meta-analysis of 17 studies found that eating processed meat (such as bacon, deli meat, and hot dogs) may raise breast cancer risk by 9 percent. Unprocessed red meat can increase the risk by 6 percent. Researchers proposed a few theories for this association:

• Estrogen given to cattle may make its way into the food supply and affect breast tissue.
• Mutagens (chemicals that cause gene mutations) are produced during the cooking process.
• Heme iron, a mineral naturally found in red meat, can increase the chances of developing breast cancer.

Eat Plenty of Fruits and Vegetables

The polyphenols and fiber in plant foods may help prevent breast cancer in a couple of ways. Polyphenols (disease-fighting nutrients) help heal damage within cells and, like fiber, can prevent potentially harmful effects of estrogen hormones and may help support a healthy metabolism.

Filling your plate with fruits and vegetables can help you switch the focus from what you “can’t have” to what you should eat more of. Eating fruits and veggies isn’t just beneficial for cancer prevention but may also help promote a healthy weight and keep common chronic diseases, like diabetes and heart disease, at bay.

Exercise Regularly

Both postmenopausal and premenopausal women can lower the chances of breast cancer by living an active lifestyle. In one study, women who engaged in the most physical activity had an up to 21 percent lower risk of breast cancer compared with those who were the most sedentary. Physical activity helps protect against cancer by leading to positive effects on estrogen levels, growth hormones, insulin regulation, and body weight. Furthermore, extended periods of sitting or lying down may contribute to cancer and other chronic diseases.

Finding exercise that you enjoy and making a conscious effort to move more often throughout the day can do a lot of good for your health and well-being. The current weekly guidelines advise adults to aim for two days a week of strength training plus 150 to 300 minutes of moderate-intensity aerobic activity (or 75 to 100 minutes of more intense exercise).

Quit Smoking

It should come as no surprise that smoking is associated with a high risk of cancer, but it’s not just lung cancer that you should be concerned about. A large study from the UK found that women with any history of smoking had a 14 percent higher risk of breast cancer than those who never smoked.

Smoking for more than 10 years increases breast cancer risk by 21 percent, and starting the habit early (before age 17) raises the risk by 24 percent. Quitting sooner rather than later provides benefits that increasingly improve health over time. For example, abstaining from cigarettes for 30 years brings the risk of breast cancer down to 10 percent.

Limit Alcohol Intake

Alcohol consumption is associated with some forms of hormone-receptor-positive breast cancer. Breast changes are also seen in young drinkers. Research shows that girls ages 9 to 15 who consume three to five alcoholic beverages per week have triple the risk of developing noncancerous lumps. For adults, having three alcoholic drinks per week increases breast cancer risk by 15 percent (compared with not drinking at all). For each additional daily drink, the risk rises another 10 percent.

Although these statistics may seem frightening, keeping the numbers in context is important. Because the chances of developing breast cancer are not very high to begin with, the increased risk associated with alcohol doesn’t make a woman that much more likely to develop the condition. Nonetheless, the link between drinking and breast cancer appears consistently in several studies.

Researchers suspect that excess calories from alcohol intake may raise breast cancer risk indirectly by causing weight gain. Alcohol also increases the body’s estrogen and folic acid levels, both of which are associated with the development of breast cancer. Instead of making alcohol an everyday habit, try to limit it to special occasions. You don’t have to eliminate alcohol, but reducing how often and how much you drink are both steps in the right direction.

Avoid Lights at Night

Several studies on people who work the night shift have shown negative health effects, including breast cancer occurrence. One potential reason for this link is overexposure to artificial light: Too much light at night can interrupt the circadian rhythm (the body’s internal clock) and lead to abnormal levels of melatonin (a hormone that helps you sleep).

If you work the night shift, consider transitioning back to day shifts by age 45 or after menopause, if possible. Understanding how your sleep schedule affects your risk of breast cancer can help you and your health care provider determine if additional preventive measures and breast cancer screenings are appropriate.

Check Your Vitamin D Levels

Scientists once believed that vitamin D’s only function was to help the body absorb more calcium. However, we now know that vitamin D is a steroid hormone that influences several processes and organs throughout the body.

When it comes to breast cancer prevention, it’s a good idea to avoid a vitamin D deficiency. In results published in Clinical Nutrition ESPEN, researchers reported a link between low vitamin D levels and a higher risk of breast cancer.

Getting more sunlight is one of the most effective ways to boost vitamin D levels. However, it’s also important to be mindful of the risk of skin cancer. Talk with your health care provider to find out if you should boost your vitamin D intake through supplements. For those who have normal levels, it’s not clear whether taking supplements would pose any added benefit or potential harm.

Use Caution With Hormone Therapy and Birth Control

Certain types of hormone replacement therapy (HRT) and hormonal birth control may increase the risk of breast cancer. However, that’s not to say they must be avoided at all costs. Some women choose to take HRT to ease menopausal symptoms and improve their quality of life despite any possibility of added risk. It’s important to discuss a medication’s potential risks and benefits with your health care provider to figure out what’s best for you.

Long-term data show that women who used combination HRT (which contains both progesterone and estrogen) were 29 percent more likely to develop breast cancer than those given a placebo. The increased risk persisted more than 10 years after they stopped using HRT. Interestingly, although earlier research linked estrogen-only HRT with an increased risk of breast cancer, this study’s findings showed that women who used this type of HRT were 23 percent less likely to receive that diagnosis.

Hormonal contraception including birth control pills and intrauterine devices can raise the risk of breast cancer, but not by much, according to the American College of Obstetricians and Gynecologists. Because hormonal birth control is highly effective against unwanted pregnancy and lowers the risk of other types of cancer (including colon, endometrial, and ovarian), it’s not necessarily helpful for all women to avoid it.

Considering alternative ways to cope with menopause symptoms or prevent pregnancy while being mindful of your combined risk factors can help you maintain your overall health.

Talk With Others Who Understand

On MyBCTeam, the social network for people with breast cancer and their loved ones, more than 57,000 members come together to ask questions, give advice, and share their stories with others who understand life with breast cancer.

Have you made any lifestyle changes in an attempt to lower your breast cancer risk or improve your breast cancer outlook? Have you discussed your risk factors with your health care provider? Share your experience in the comments below, or start a conversation by posting on your Activities page.