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Low Fat Vs. Low Carb Diet Studied in Breast Cancer

COLUMBUS, Ohio – COLUMBUS, Ohio – It is a question women have been asking for years, but despite hundreds of studies, the answer just isn’t clear: How are diet and exercise related to the risk of breast cancer?

Doctor Electra Paskett
Electra D. Paskett, Ph.D.
Dr. Electra Paskett, associate director for population sciences at The Ohio State University Comprehensive Cancer Center, hopes a new study examining a low-fat vs. a low-carbohydrate diet may clear up some of the confusion.

Paskett, along with colleagues at Ohio State and Wake Forest University School of Medicine, will spend the next 18 months comparing the impact of each regimen on risk factors for breast cancer among premenopausal women at high risk of the disease either because they are overweight or obese.

“There is so much confusion out there,” says Paskett. “Women recognize a relationship between nutrition and health, but they are being bombarded with conflicting and misleading information from the promotion of fads and quick fix-it schemes rather than scientific fact. The bottom line is that no one has any definitive answers.”

Study participants must be at least 30 years old, and have a body mass index (BMI) between 25 and 34. (BMI can be calculated by dividing weight in kilograms by height in meters, squared. For example, a woman who is 5’6” tall and weighs 156 has a BMI of 25.)

The women will be randomized to one of two diet plans, a low-carbohydrate arm or a low-fat arm.

Researchers point out, however, that diet alone may not be enough to reduce a woman’s risk of breast cancer, especially if she is overweight. That’s why an important part of the study will be an exercise program that will be tailored to each participant’s needs.

Beth Miller, a registered dietitian who will consult with the women, says the exercise program is designed to help them lose up to two pounds per week if they follow it closely. “We don’t know which diet might be more helpful in reducing the risk of breast cancer. But we do know that just losing weight all by itself will promote health, regardless of diet,” says Miller, of the Arthur G. James Cancer Hospital and Richard J. Solove Research Institute.

Participants will be expected to exercise regularly, mostly through walking, building up to 10,000 steps per day, measured by a pedometer, five times per week.

Researchers are hoping that regular feedback about weight loss or changes in key breast cancer biomarkers will help the women stick to their programs. “Adherence is always an issue in diet studies, and anything that we can show that can help women do what’s good for them will be very useful knowledge,” says Paskett.

There is evidence that both dietary fat and high carbohydrate intake are related to increased vulnerability to breast cancer. Laboratory tests have shown that animals placed on high-fat diets develop breast tumors more frequently than those on a low-fat diet. In addition, extra body weight alone has been shown to be a risk factor for breast cancer, especially among post-menopausal women. The more fat a woman carries is directly related to how much estrogen she has available to be converted into estradiol, the biologically active form of estrogen that can promote the growth of breast cancer cells.

There has been much less attention paid to sugar and carbohydrate consumption, however, but Paskett says laboratory studies suggest they may be problematic, too.

“Some studies show that carbohydrates give cancer cells more energy and contribute to the activity of insulin growth factor (IGF), a hormone that stimulates the growth of cancerous cells.” Paskett says data indicating a positive relationship between IGF levels and breast cancer risk appears to be strongest in pre-menopausal women.

The study is funded by The Breast Cancer Research Foundation, founded by Evelyn H. Lauder.

The Ohio State University Comprehensive Cancer Center is a network of interdisciplinary research programs with over 200 investigators in 13 colleges across the OSU campus, the Arthur G. James Cancer Hospital and Richard J. Solove Research Institute and Children’s Hospital, in Columbus. OSUCCC members conduct research on the prevention, detection, diagnosis and treatment of cancer, generating over $75 million annually in external funding.

For more information about the study, call 614-293-6917.

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