7 lifestyle factors that lower breast cancer risk
Impactful steps midlife women can take
October is Breast Cancer Awareness Month. They reminded me of this when I went to schedule my mammogram and they didn’t have an opening until April.
“Sorry it’s breast cancer awareness month.”
One in eight women will get breast cancer and the risk increases at midlife. So, what better time to discuss the daily things we can do to help reduce our risk.
1. Watch your alcohol intake, especially when on hormone therapy
In a 2018 update The World Cancer Research Fund and the American institute of Cancer Researcher reviewed 50 studies and concluded that for every 10 gram increase in alcohol, the risk of cancer in premenopausal women increased by 5%. In postmenopausal women, that jumps to 9%.
As I’ve pointed out before, women on hormone therapy may be at greater risk. In every study I’ve found to date, the risk of breast cancer is significantly higher when a woman drinks and is also on menopausal hormone therapy. This is because alcohol increases estrogen levels, which are higher in these women.
In my big review on alcohol and midlife women, I detail how this research link is not new:
MHT users drinking alcohol increased their estrogen three-fold for about five hours with no increases seen in women not taking hormones. And a review back in 1999 concluded: “Alcohol and hormone exposure together may act synergistically to create increased breast cancer risk.”
For some women, stopping drinking is the best choice, yet others may opt for moderate intake. Apps like Sunnyside can help you cut back and mindfully drink.
2. Get those B vitamins
Although not all studies show benefit, B vitamins may be particularly beneficial for protecting women who drink. According to a 2014 review, four out six trials showed benefits to consuming dietary folate in women who drink.
The NutrNet-Sante study followed 27,853 women >45 for just over 4 years. They measured diet and supplemental intake and found protective effects of vitamin B6 and thiamin.
Researchers think B vitamins' role in one carbon metabolism may play a role in their protection in those who drink. This is another reason to consider a multivitamin with B vitamins as I discuss here.
Alcohol’s effects on oxidative stress, cell proliferation, steroid hormones, and one-carbon metabolism may explain, in part, the observed associations with breast cancer risk
-Freudenheim JL, Research, 2020; 40(2): 11
3. Include a Vitamin-A rich (or two) fruit or veggie every day
Vitamin A from plant sources may help reduce risk of breast cancer. Higher carotenoid levels, especially in women at higher risk for breast cancer, reduced risk by 30-60% and premenopausal African Americans.
And if you get breast cancer, higher intakes have been shown to improve survival. See the list below for ideas.
I always aim for a rich source of vitamin A every day. When I’m feeling hungry while cooking, I chomp on baby carrots.
4. Participate in regular exercise most days
According to the Susan G. Komen website, women who exercise have a 10-20% reduced risk of getting breast cancer.
Last year Texas A&M researchers dug deeper into potential mechanisms in an animal study. Unidentified factors released during muscle contraction suppressed signaling within breast cancer cells, reducing the growth of tumors.
“The decreased risk of breast cancer with exercise comes from the idea that if you have pre-neoplastic cells and you’re exercising a lot and slowing their growth, maybe those precancerous cells can be destroyed by the body before they start taking over,” lead researcher Amanda Davis said in a press release.
More studies are being done to identify the factors released during exercise. Just add it to the long list of benefits of regular exercise.
“These data are exciting because they show that during muscle contraction, the muscle is actually releasing some factors that kill, or at least decrease the growth of, neoplastic (abnormal, often cancerous) cells.”
5. Track your vitamin D levels
Most, but not all, studies show an inverse relationship between vitamin D status and breast cancer. What may matter more than vitamin D intake is blood levels.
A 2019 study analyzed 70 studies on vitamin D blood levels (50 studies) and intake (20 studies). Their analysis revealed that for every 5 nmol/l increase in vitamin D, there was a 6% decrease in breast cancer risk.
Both premenopausal and postmenopausal women showed reduced risk. Yet there was no reduced risk for vitamin D intake.
There’s also interesting evidence that vitamin D decreases breast cancer mortality. In a 2017 review, women with vitamin D lower than 20ng/mL had a much higher risk of developing metastatic breast cancer.
Of course, more research needs to be done to determine actual target levels as I lay out in this post. But for now, check your vitamin D biomarkers. If you haven't got my free biomarker guide, subscribe below.
6. Don’t forget about iodine & selenium
Two nutrients that fall under the radar for breast health are iodine and selenium. We need iodine for normal breast development with iodine receptors present in breast tissue, enabling the uptake of iodine.
In the 2017 Journal of Cancer, Jay Rappaport from the Department of Neuroscience, Lewis Katz School of Medicine Temple University, makes the case that decreased iodine intake plays a role in the rise of younger women being diagnosed with aggressive breast cancers.
The reasoning is that studies in rats show iodine deficiency results in hyperresponsiveness to estradiol within breast tissue. Given that iodine intakes have declined, this is a problem.
Urinary iodine levels decreased from 320ug/L in 1971-1974 to 145 ug/L in 1988-1994. And people with urinary iodine <50 has increased 5.6 fold from 2.6% to 14.5% in that same time period.
But selenium may play a role here as well. A study in a 2020 study in Cancer Epidemiology, Biomarkers & Prevention showed that iodine status only matters when selenium intakes were adequate. So, these nutrients together — which is also true for thyroid health — are important to watch.
Selenium by itself may affect the survival of breast cancer. A 2021 study in Nutrients with 538 women revealed that 10-year survival was 65.1% for women in the lowest quartile for serum selenium but it was 86.7% for women in the highest quartile.
For food sources, check out my post of 7 Foods Women Over 40 Should be Eating
7. Include adequate fiber, especially soluble fiber
In 2020, researchers performed a systematic review and meta-analysis on prospective studies examining the relationship between fiber intake and breast cancer.
Both pre and postmenopausal women with high intakes of fiber had reduced risk of breast cancer. The findings were most consistent for soluble fiber. Soluble fiber also helps to lower cholesterol, another important factor for midlife women.
My goal is always to get two sticky, soluble fiber food sources a day. For example, oats as part of my breakfast and beans topped on my salad.
Although these 7 factors help to reduce the risk, early detection is key as half of women diagnosed with breast cancer have no risk factors.
So, make that appointment. It might take a while for them to fit you in!