In:
Cancer Epidemiology, Biomarkers & Prevention, American Association for Cancer Research (AACR), Vol. 20, No. 9 ( 2011-09-01), p. 1815-1821
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 (E2) and estrone sulfate (E1S) were assessed in NAF and estrone (E1) in serum only, using highly sensitive radioimmunoassays. Mixed-effects regression models accounting for repeated measures and left-censoring limits were applied. Results: Mean E2 and E1S 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 E2 (P = 0.76), E1 (P = 0.86), or E1S (P = 0.56). Within individuals, NAF and serum levels of E2 (rs = 0.37; P & lt; 0.001) but not of E1S (rs = 0.004; P = 0.97) were correlated. E2 and E1S in NAF and serum were strongly associated (rs = 0.78 and rs = 0.48; P & lt; 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. Cancer Epidemiol Biomarkers Prev; 20(9); 1815–21. ©2011 AACR.
Type of Medium:
Online Resource
ISSN:
1055-9965
,
1538-7755
DOI:
10.1158/1055-9965.EPI-11-0363
Language:
English
Publisher:
American Association for Cancer Research (AACR)
Publication Date:
2011
detail.hit.zdb_id:
2036781-8
detail.hit.zdb_id:
1153420-5
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