The research:
Fat cells produce estrogen and other hormones that cause your cells to divide. If you are overweight or obese, you will produce more of these hormones than your body needs. This increases the chance that cells in your breasts will become cancer cells.
Your risk of breast cancer rises if you are moderately to significantly overweight. Factors that increase your risk include:
- a Body Mass Index (BMI) of 25 or more
- a high percentage of body fat
- extra weight around your waist and abdomen, rather than on your hips and thighs
- weight gain later in life.
The research shows quite clearly that after menopause, overweight women have a higher risk of breast cancer. It is true that before menopause, excess weight appears to protect against breast cancer. However, because extra weight increases your risk of many other diseases, it’s always better to maintain a healthy weight throughout your life.
What you can do:
You can use a Body Mass Index (BMI) calculator to find out whether your weight falls within the healthy range for your height. A BMI of between 18.5 and 24.9 is generally considered normal.
Eating a healthy diet and getting regular exercise are the best ways to manage your weight. There are many resources available online that offer information and support to help you achieve and maintain a healthy body weight. You can also ask for advice from your doctor.
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The research:
Regular physical activity helps to keep hormones in your body at healthy levels. This is important because when you produce high levels of some hormones such as estrogen, your risk of breast cancer can increase.
Research has shown that regular exercise reduces the risk of breast cancer. This is especially true for younger women during adolescence, as well as older women after menopause. It’s estimated that if women in BC who don’t currently exercise became physically active, we could reduce the province’s breast cancer rate by 11%.
When it comes to reducing their risk of breast cancer through physical activity, studies suggest that certain women may benefit the most. This includes women who:
- have previously given birth
- have a healthy body weight
- have no family history of breast cancer.
What you can do:
It is important to maintain regular physical activity throughout your life. Most experts agree that to effectively reduce your risk of breast cancer, you need to engage in moderate activity most days of the week. Vigorous activity is even better for your breast health.
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The research:
Drinking too much alcohol is a risk factor for many diseases, including breast cancer. While we still don’t know exactly how alcohol leads to cancer, it is thought that alcohol damages DNA in cells. DNA damage increases the risk of cancer.
There is a large amount of research showing that alcohol increases a woman’s risk for breast cancer before and after menopause. Studies also suggest that the more you drink, the greater your risk. Women who are heavy drinkers and who take hormone therapy for menopause symptoms are especially at risk for breast cancer.
It’s true that research has shown that drinking small amounts of alcohol every day may benefit your heart health. However, it’s important to recognize that when it comes to breast cancer, no amount of alcohol has been found to be “risk-free.”
What you can do:
If you don’t drink alcohol, don’t start.
If you do drink alcohol, consider reducing the amount you drink. Canada’s Low Risk Alcohol Drinking Guidelines recommend that to reduce their risk for several long-term health problems, women should limit their drinking to no more than 10 drinks a week, and no more than 2 drinks a day most days. Breast cancer experts recommend even less alcohol – less than one drink per day. Remember that when it comes to preventing breast cancer, less alcohol is always better, and no alcohol is best.
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The research:
Breastfeeding causes changes in the body’s chemical balance, which may provide protection from breast cancer. It lowers pH levels and reduces the production of estrogen, which are both linked to lower breast cancer risk. Milk production may also help to “flush out” cancer-causing substances in breast tissue.
The more time a woman breastfeeds over her lifetime, the less her risk of breast cancer. Studies have shown that compared to women who have never breastfed, women who breastfeed for a total of three years have a 10-20% reduction in breast cancer risk. If you breastfeed for less time, you won’t get as much benefit, but your risk will still be lower compared to women who have never breastfed. The research also suggests that breastfeeding is especially protective for women who have a family history of breast cancer.
What you can do:
If you are planning to have a family, educate yourself about the many health benefits of breastfeeding for baby and mother. Look into the resources that are available to help you breastfeed successfully. If you are currently breastfeeding your baby, try to continue for as long as possible – ideally for at least several months.
Learn more:
Breastfeeding and breast cancer
Breastfeeding information and support
of hormone therapy
for menopause symptoms
The research:
Research shows that combined hormone replacement therapy (HRT) increases certain health risks, and protects against others. Many studies around the world have looked at the connection between HRT and increased breast cancer risk. The results show that women who use HRT have a higher risk of breast cancer than women who have never used HRT, and that the risk increases the longer a woman uses these therapies. One study found that for women receiving combined HRT for five or more years, their breast cancer risk was 35% higher. There is even greater risk among HRT users who are also heavy alcohol drinkers.
The good news is that after women stop taking these hormone therapies, their risk of breast cancer will decrease again over time.
What you can do:
If you are considering taking hormone therapy to relieve your menopause symptoms, it’s important to understand that using combined hormone replacement therapy (HRT) increases your risk of breast cancer. Your doctor can help you weigh the different risks and benefits to decide what’s right for you. If you do decide to use this therapy, take the lowest dose possible, for the shortest possible time.
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