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While many of the factors that influence whether you're at risk for breast
cancer are outside your control, experts say there are things you can do to
improve the odds. Just as diet, weight, and exercise have a big influence on
your overall health, they may make a difference in your breast cancer risks as
well.
"There are a lot of factors that contribute to breast cancer risk that you have
no control over: what age you started your period, what age you had children,
what age you began menopause, and family history of breast cancer," says
Colleen Doyle, MS, a registered dietitian and nutrition and physical activity
director for the American Cancer Society. (Having your first child after age 30
or never having children puts you at higher risk; so do getting your first
period before age 12, starting menopause after age 50, or having family members
who got the disease.)
"You can't do anything about these risk factors,'' says Doyle, "but you can do
something about your diet and weight, and you can do something about your level
of physical activity."
A Weighty Matter
Research has consistently shown a link between obesity and breast cancer in
postmenopausal women, experts say. Consider a study of more then 62,000 women,
published in Cancer Epidemiology, Biomarkers & Prevention.
"For women who gained 21-30 pounds throughout their adult lifetime, meaning
since the age of 18, they were at a 40% increased risk for breast cancer,
post-menopause," says Heather Spencer Feigelson, PhD, MPH, co-author of the
study. "Women who gained 70 pounds in adult life were at twice the risk,
compared to women who stayed within five pounds of their weight." (None of the
women in the study were taking hormone replacement therapy.)
Why the increased risk with the increase in weight?
The more fat a woman has, the more estrogen she will produce, explains Spencer
Feigelson, who is also a senior epidemiologist with the American Cancer
Society. After menopause, the more estrogen a woman's body produces, the higher
her risk of breast cancer. So having lots of body fat increases estrogen
levels, and therefore, breast cancer risk.
The Nutrition Connection
Aside from keeping calories at a reasonable level to avoid weight gain, what can
you eat to help ward off breast cancer?
As complex as nutrition is, it boils down to simple rules that have a ripple
effect across your entire body, explains Susan Moores, RD, a spokeswoman for
the American Dietetic Association.
"Everything that I tell you now is very much the same as that you would hear for
any other health condition," Moores says. "If you are doing some or all of
these things, it might lower your risk for breast cancer, but it can also do
great things for your heart, osteoporosis, and other cancers."
As for specific foods, "there is interesting research around the possible
beneficial impact of omega-3 fatty acids, which are found in fish," says
Moores. Fish high in omega-3 fatty acids include coldwater fish such as salmon,
tuna, herring, mackerel, sturgeon, and anchovies. Walnuts and flaxseed are
plant-based sources of omega-3.
Preliminary studies have also indicated that "vitamin D and calcium ...
particularly in low-fat dairy food, could reduce tissue changes in the breast,"
Moores says. And women who have changes in breast tissue are thought to be at a
greater risk for breast cancer.
Again, says Moores, vitamin D and calcium go beyond breast cancer -- they also
help prevent osteoporosis.
"Talk about a population that needs both of these, for more reason than one,"
says Moores. "Ninety to 95% of girls and women aren't getting enough calcium.
And for women over 19, just about 80% are not getting enough vitamin D. So
these are sorely lacking in many women's diets."
And then there are fruits and vegetables. "The more the better," says Moores.
"Especially those really colorful fruits and veggies. ... Pull in as much color
as possible and get those lycopenes [found in red produce like tomatoes] and
beta-carotenes [found in orange produce like carrots]."
As much as we love those morning cups of coffee, they might not be helpful when
it comes to improving the odds.
"Too much caffeine isn't linked directly with breast cancer, but it is linked
with a change in breast tissue," says Moores. "Women that have changes in
breast tissue are at a greater risk for breast cancer. Now, that's a huge leap,
but it does seem that in high amounts, 4-5-plus caffeinated beverages a day,
breast tissue could be altered, and that possibly could increase your risk for
breast cancer."
Your evening cocktails could also increase your risk.
"Women who have too much alcohol are at a higher risk for breast cancer," Moores
tells WebMD.
A 2003 study in the Journal of the National Cancer Institute showed
that women aged 49 to 54 may be most at risk from alcohol. Researchers found
that one to two drinks a day in these women increased levels of the hormone
leptin by 24%. Leptin has been linked to an increased breast cancer risk.
The American Cancer Society recommends that women have no more than one
alcoholic drink a day -- one drink being a five ounce glass of wine, one 12
ounce beer, or one ounce of liquor.
Exercise, of Course
As with most issues related to your health, exercise plays a role in breast
cancer risks. And it's not just because working out helps keep your weight
down.
"There is convincing evidence that increasing physical activity reduces risk of
breast cancer, not only because of weight control but also by helping to reduce
circulating hormones that are associated with breast cancer -- primarily
estrogen and insulin," says Doyle.
But to get these benefits, you'll need to do more than take a stroll in the
park. The exercise you should aim for is aggressive.
"The overall recommendation for physical activity is at least 30 minutes, five
or more days a week," says Doyle. "For breast cancer, it's even more vigorous
-- 45 minutes of moderate or vigorous exercise five or more days a week."
A Healthy Lifestyle
Of course, even if you do all of these things, there's no guarantee you won't
get breast cancer. The good news, says Doyle, is that making healthy lifestyle
changes will benefit you in countless other ways.
"The message we are trying to get across is that, hey, the things we are saying
for breast cancer will help with diabetes, heart disease, and other conditions,
as well: Eat a healthy, well-balanced diet, maintain a healthy weight, and
exercise regularly."
By Heather Hatfield
Reviewed By Kathleen Zelman, MPH, RD, July 25, 2007.
Originally published Oct. 4, 2004.
Medically Updated July 25, 2007.
SOURCES: Cancer Epidemiology, Biomarkers & Prevention.
February 2004. Colleen Doyle, MS, RD, nutrition and physical activity director,
American Cancer Society, Atlanta. Susan Moores, RD, spokeswoman, American
Dietetic Association, St. Paul, Minn. Heather Spencer Feigelson, PhD, MPH,
senior epidemiologist, American Cancer Society, Atlanta. WebMD Medical News:
"Alcohol May Increase Breast Cancer Risk."
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