||5R03CA096414-02 Interpret this number
||Fox Chase Cancer Center
||Dietary Soy/Isoflavones and Urinary Estrogen Metabolites
DESCRIPTION (provided by applicant):
Research on potential cancer-protective effects of soy and isoflavones has led
to an increase in the availability and consumption of soy products in the US.
Yet conflicting scientific evidence raises the concern that high levels of
intake might actually increase breast cancer risk. Whether current levels of
soy and soy isoflavone intake are sufficiently high to affect breast cancer
risk is unknown largely because of a lack of convenient, current, and
validated methods of assessing intake. The objectives of the proposed study
are to (1) evaluate the validity of overnight urine samples as a method of
assessing soy isoflavone intake, and (2) examine associations between
soy/isoflavone intake and urinary estrogen metabolites. Participants will be
drawn from a program at Fox Chase Cancer Center for women at high breast or
ovarian cancer risk. The study will include 50 women with either very high or
low soy intake based on questionnaire data. Participants will complete a
soyfood questionnaire and provide four 24-hour urine specimens over a one
month period, with overnight samples collected in separate containers. Urines
will be analyzed for isoflavones, primarily daidzein and genistein, and for
estrogen metabolites including 2-, 4-, and 16alpha-hydroxy estrogens. Isoflavone
levels in overnight urine samples will be evaluated for validity by examining
their correlations with isoflavone levels in 24-hour urine specimens. We will
use multiple linear regression to examine associations of soy/isoflavone
intake with urinary estrogen metabolites. The proposed research will provide useful information towards assessment of soy/isoflavone intake in a non-Asian
sample. It is also an opportunity to add to limited knowledge on
soy/isoflavone intake and its association with urinary estrogen metabolites as
markers of breast cancer risk. Findings from this research will contribute
information towards a soy supplementation trial to evaluate modification of
soy/isoflavone intake as a means of reducing risk of breast cancer, a disease
for which few preventive measures are available.
Food frequency questionnaires and overnight urines are valid indicators of daidzein and genistein intake in U.S. women relative to multiple 24-h urine samples.
, Olufade T.
, Kurzer M.S.
, Wahala K.
, Fang C.Y.
, van der Schouw Y.T.
, Daly M.B.
Nutrition and cancer, 2008; 60(5), p. 619-26.