UCLA Study Finds a Low Fat, High-Fiber Diet Lowers Breast Cancer Risk Factors - Slows Tumor Cell Growth
followed a regime of daily exercise and the Pritikin Diet, a diet low
in fat and high in fiber-rich fruits, vegetables, and whole grains,
lowered their levels of serum estradiol, insulin and insulin-like
growth factor, all independent risk factors for development of breast
cancer, according to results of a new study by UCLA researchers.
The researchers found that the serum changes reduced the growth and induced apoptosis (cell death) of breast cancer cells in in vitro laboratory testing.
"This is the
first study to my knowledge to show that lifestyle changes can induce
apoptosis, or cell death, in breast cancer cells" said James Barnard,
Ph.D., professor of physiological science at UCLA and lead investigator
of the study.
UCLA colleagues studied 26 postmenopausal women who attended a 13-day
program of diet and exercise at the Pritikin Longevity Center & Spa
in Aventura, Florida. The researchers collected blood serum samples
from the women on day 1 ("entry" samples) and day 13 ("exit" samples)
of their Pritikin Program. In laboratories at UCLA, the women's
bloodserums were placed in three different sets of culture dishes, each
containing a different line of breast cancer cells.
the "entry" blood samples, the women's "exit" samples significantly
decreased the rate of tumor cell growth in all three types of breast
cancer. Adopting an exercise regime and a low fat, high-fiber diet
resulted in serum changes that slowed the growth of breast cancer cells
by as much as 19%.
researchers also noted a 20 to 30% increase in tumor cell death
(apoptosis) in the cell cultures using "exit" blood samples compared to
those exposed to the "entry" samples.
these results suggest that exercise combined with a Pritikin-type diet
can result in a significant reduction in the risk for breast cancer,"
commented Dr. Barnard.
exciting research because it shows that women can make changes in a
very short period of time that can have a dramatic impact on their
health - in this case, on the growth and death of breast cancer cells,"
said William McCarthy, PhD of UCLA's School of Public Health.
what might be inhibiting tumor growth as well as destroying tumor
cells, the scientists measured blood serum levels of estradiol (a form
of estrogen), insulin, and insulin-like growth factor (IGF-1). All
three have been identified as independent risk factors for the
development of breast cancer.
By the end of
the women's 13-day program at the Pritikin Longevity Center, all three
risk factors had plummeted. Estradiol levels in the women on hormone
replacement therapy fell on average 34%; among those not taking
hormones, estradiol decreased 37%. Among all 26 women, insulin levels
fell 29%, and IGF-1 levels dropped 19%.
study, funded by the University of California, Los Angeles, supports
another study by UCLA researchers, announced in May at the American
Society of Clinical Oncology's annual meeting. That study found that
among more than 2,400 women who had been treated for early stage breast
cancer, those who replaced many of the fatty foods in their diet with
healthful low-fat foods like fruits and vegetables were significantly
less likely to have their cancer return within the next five years than
those who continued to eat a typically American high-fat diet.
epidemiological data indicates that lifestyle is a major factor in the
development of breast cancer," commented Dr. Barnard. "Several large
population studies have found that countries with the lowest intake of
dietary fats have the lowest incidences of breast cancer, as well as
colon and prostate cancer."
women raised in affluent cultures like the United States, full of
high-fat fare like French fries and cheeseburgers, suffer the highest
rates of breast cancer in the world - an 80% increase compared to
cultures like Okinawa, Japan, where dietary fat intake is low, about
20% of total calories, and intake of fresh, fiber-filled foods like
fruits and vegetables is high.
found, too, that when women from low-breast-cancer-risk countries like
Japan and China leave their traditional diets and migrate to countries
like the U.S., their rates of breast cancer rise to the same high
levels of their Western neighbors, and within just two generations.
"And as Asian
countries like Japan are now becoming more Westernized, their breast
cancer rates are going up substantially," noted Dr. Barnard.
telling people for years that if they want to avoid most of the health
problems we have in this country, they should go on a low-fat,
high-fiber diet like Pritikin and do about an hour of aerobic exercise
every day," said Barnard, who has published more than 100 studies over
the past three decades on the relationship between healthful lifestyles
and disease prevention.
is the most common cancer in U.S. women, and the second leading cause
of cancer deaths in American women today (after lung cancer). The
American Cancer Society estimates that in 2005, approximately 211,240
women in the United States will be diagnosed with invasive breast
For more information on UCLA’s department of physiological science, visit www.physci.ucla.edu/. For more information on UCLA’s School of Public Health, visit www.ph.ucla.edu/. For more information on the Pritikin Longevity Center & Spa, visit www.pritikin.com/.