High fiber/low fat
diet does not appear to reduce risk of Breast
Cancer recurrence more than ‘5-A-Day’ diet
Newswise — Women with early
stage breast cancer who adopted a diet very high
in vegetables, fruit and fiber and low in fat
did not have a lower risk of breast cancer
recurrence compared to women who followed a diet
of five or more servings a day of fruit and
vegetables (the “5-A-Day” diet), according to a
study in the July 18 issue of JAMA.
“Considerable evidence from
preclinical studies indicates that plant-derived
foods contain anticarcinogens. A comprehensive
review of the literature found that a diet high
in vegetables and fruit probably decreases
breast cancer risk and that a diet high in total
fat possibly increases risk. However, evidence
of an association between a diet high in
vegetables and fruit and low in total fat and
prevention of cancer progression has been mixed
in epidemiological studies,” the authors write.
John P. Pierce, Ph.D., of
the University of California, San Diego, La
Jolla, Calif., and colleagues conducted the
Women’s Healthy Eating and Living (WHEL) Study
to assess whether a dietary pattern very high in
vegetables, fruit, and fiber and low in fat
reduces the risks of recurrent and new primary
breast cancer and all-cause death among women
with previously treated early stage breast
cancer. The randomized controlled trial included
3,088 women who were previously treated for
early stage breast cancer (18 to 70 years old at
diagnosis). Women were enrolled between 1995 and
2000 and followed up through June 2006.
The intervention group (n =
1,537) was randomly assigned to receive a
telephone counseling program supplemented with
cooking classes and newsletters that promoted
daily targets of five vegetable servings plus 16
oz. of vegetable juice; three fruit servings; 30
grams of fiber; and 15 percent to 20 percent of
energy intake from fat. The comparison group (n
= 1,551) was provided with print materials
describing the “5-A-Day” dietary guidelines.
From comparable dietary
patterns at baseline, the intervention group
achieved and maintained the following
statistically significant differences vs. the
comparison group through four years: servings of
vegetables, +65 percent; fruit, +25 percent;
fiber, +30 percent, and energy intake from fat,
−13 percent. Throughout the study, women in both
groups received similar clinical care.
During the study, 518 participants had a breast
cancer event, including 256 participants (16.7
percent) in the intervention group and 262
participants (16.9 percent) in the comparison
group. There were 315 deaths reported within the
study period, with 155 (10.1 percent) in the
intervention group and 160 (10.3 percent) in the
comparison group. More than 80 percent of all
deaths were due to breast cancer. No significant
benefit in preventing breast cancer recurrence
was observed overall among population subgroups
characterized by demographic characteristics,
baseline diet, or type of initial tumor or
breast cancer treatment.
“In conclusion, during [an
average] 7.3-year follow-up, we found no
evidence that adoption of a dietary pattern very
high in vegetables, fruit, and fiber and low in
fat vs. a 5-a-day fruit and vegetable diet
prevents breast cancer recurrence or death among
women with previously treated early stage breast
cancer,” the authors write.
(JAMA. 2007;298(3):289-298.
Available pre-embargo to the media at
www.jamamedia.org)
Editor’s Note: Please see
the article for additional information,
including other authors, author contributions
and affiliations, financial disclosures, funding
and support, etc.
Editorial: Fat, Fruits,
Vegetables, and Breast Cancer Survivorship
In an accompanying
editorial, Susan M. Gapstur, Ph.D., and Seema
Khan, M.D., of the Feinberg School of Medicine,
Northwestern University, Chicago, write that
there are a number of questions that need to be
examined regarding diet and cancer risk.
“Several issues remain to
be addressed regarding the effects of dietary
interventions on breast cancer prognosis. It is
becoming increasingly clear that evaluating
dietary effects is complex and requires careful
monitoring to ensure adherence to the
intervention goals so that any hypothesized
effect can be detected. In addition, studies
assessing whether breast cancer prognosis would
be improved with interventions that focus on the
complex components of energy balance (i.e.,
physical activity and energy intake) appear
warranted. Unfortunately, available data do not
support best practice dietary recommendations to
improve long-term prognosis for early stage
breast cancer survivors.”
