THURSDAY, Dec. 8 (HealthDay News) -- Increased consumption of
carbohydrate-rich foods, especially starches, may boost the risk of
breast cancer recurrence, new research finds.
Researcher Jennifer Emond, a public health doctoral student at
the University of California, San Diego, looked at changes in the
amount of carbohydrates, particularly starchy foods such as
potatoes, that breast cancer survivors ate over a one-year period.
Then she tracked the number of recurrences.
"Women who increased their carbohydrates and particularly their starch intake had a greater risk of recurrence than the women who decreased [it]," she said.
A link between a high-carb diet and a higher breast cancer risk
has been reported before, but this new study focused particularly
on starchy carbs, said Emond. She was scheduled to present the
findings this week at the 2011 San Antonio Breast Cancer
Carbohydrates provide needed nutrients and energy, but some
carbs are healthier than others. Refined carbohydrates, such as
white breads and white pasta, contain more starch than whole
grains. "We didn't pinpoint the exact foods," Emond said.
Emond looked at a subset of women who participated in the
Women's Healthy Eating and Living Dietary Intervention Trial, which
evaluated the effects of a plant-based diet for breast cancer
She divided the roughly 2,650 women into four groups, based on
lowest to highest carbohydrate intake. She found that cancer
recurred in 9.7 percent of those who decreased starch consumption
the most compared with 14.2 percent of those with the biggest
increase in starch consumption.
The women reported their carb intake at the start of the study
and a year later. Carbohydrate intake was about 233 grams a day at
the study's start. Those whose cancer recurred had an average
increase in carbohydrates of 2.3 grams a day. Those who did not see
a recurrence had an average decrease of 2.7 grams of starch a
Changes in starch consumption were behind nearly half the
carbohydrate intake change, she found. Those whose cancer did not
return decreased starch intake by 8.7 grams a day, while those with
a recurrence decreased starch by only 4.1 grams a day, she
According to the U.S. Department of Agriculture, one slice of
bread has 12.5 grams of carbohydrate, of which 10 grams are starch.
A cup of pasta has 43 grams of carbs, 36 of which are starch.
Emond said she cannot explain the link between starch and breast
cancer recurrence with certainty. However, starchy foods boost
insulin levels, and elevated insulin levels have been linked with
higher breast cancer risk, she said. The insulin may stimulate the
growth of tumor cells, she explained.
The increased risk with higher starch intake held even when
weight changes were taken into account, Emond said. Obesity and
breast cancer have long been linked.
Marji McCullough, strategic director of nutritional epidemiology
for the American Cancer Society, said the findings are noteworthy.
"This is an important area of research because women who have been
diagnosed with breast cancer want to know how to lower their risk
of recurrence," she said.
But it's too soon to advise making any dietary changes,
McCullough said. "Dietary recommendations change when several
studies show the same thing," she said.
The effect of diet on breast cancer recurrence risk is much less
clear than the data on the importance of maintaining a healthy body
weight, she said.
"The American Cancer Society recommends that breast cancer survivors strive to achieve and maintain a healthy weight through a mostly plant-based, varied diet and regular physical activity," McCullough said.
Emond agreed it's too soon to make new diet recommendations.
However, she suggested women follow the 2010 Dietary Guidelines for
Americans, which recommend limiting foods with added sugars that
contribute to starch intake, she said.
In a second study involving diet and breast cancer, researchers
found that following a low-carbohydrate diet just two days a week
produced more significant weight loss than a standard low-calorie
diet followed daily. People following the intermittent diet for
four months lost an average of 9 pounds while the other dieters
lost an average of 5 pounds, the British researchers found.
The two-day-a-week low-carb plan was also better than the daily
diet at lowering blood levels of insulin, the researchers said.
McCullough called that finding ''intriguing."
Because this research was presented at a medical meeting, the
data and conclusions should be viewed as preliminary until
published in a peer-reviewed journal.
To learn more about diet and breast cancer risk, visit the
American Cancer Society.
Please be aware that this information is provided to supplement the care provided by your physician. It is neither intended nor implied to be a substitute for professional medical advice. CALL YOUR HEALTHCARE PROVIDER IMMEDIATELY IF YOU THINK YOU MAY HAVE A MEDICAL EMERGENCY. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with any questions you may have regarding a medical condition.
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