Display Settings:

Format

Send to:

Choose Destination
We are sorry, but NCBI web applications do not support your browser and may not function properly. More information
Cancer Epidemiol Biomarkers Prev. 2011 Sep;20(9):1815-21. doi: 10.1158/1055-9965.EPI-11-0363. Epub 2011 Jul 8.

Estrogen levels in nipple aspirate fluid and serum during a randomized soy trial.

Author information

  • 1University of Hawaii Cancer Center, 1236 Lauhala Street, Honolulu, HI 96813, USA. gertraud@cc.hawaii.edu

Abstract

BACKGROUND:

On the basis of hypothesized protective effect, we examined the effect of soy foods on estrogens in nipple aspirate fluid (NAF) and serum, possible indicators of breast cancer risk.

METHODS:

In a crossover design, we randomized 96 women who produced 10 μL or more NAF to a high- or low-soy diet for 6 months. During the high-soy diet, participants consumed 2 soy servings of soy milk, tofu, or soy nuts (∼50 mg of isoflavones per day); during the low-soy diet, they maintained their usual diet. Six NAF samples were obtained using a FirstCyte aspirator. Estradiol (E(2)) and estrone sulfate (E(1)S) were assessed in NAF and estrone (E(1)) in serum only, using highly sensitive radioimmunoassays. Mixed-effects regression models accounting for repeated measures and left-censoring limits were applied.

RESULTS:

Mean E(2) and E(1)S were lower during the high-soy than the low-soy diet (113 vs. 313 pg/mL and 46 vs. 68 ng/mL, respectively) without reaching significance (P = 0.07); the interaction between group and diet was not significant. There was no effect of the soy treatment on serum levels of E(2) (P = 0.76), E(1) (P = 0.86), or E(1)S (P = 0.56). Within individuals, NAF and serum levels of E(2) (r(s) = 0.37; P < 0.001) but not of E(1)S (r(s) = 0.004; P = 0.97) were correlated. E(2) and E(1)S in NAF and serum were strongly associated (r(s) = 0.78 and r(s) = 0.48; P < 0.001).

CONCLUSION:

Soy foods in amounts consumed by Asians did not significantly modify estrogen levels in NAF and serum.

IMPACT:

The trend toward lower estrogen levels in NAF during the high-soy diet counters concerns about adverse effects of soy foods on breast cancer risk.

PMID:
21742946
[PubMed - indexed for MEDLINE]
PMCID:
PMC3169755
Free PMC Article

Images from this publication.See all images (2)Free text

Figure 1
Figure 2
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk