title: The volume of nipple aspirate fluid is not affected by 6 months of treatment with soy foods in premenopausal women.
abstract: Based on the hypothesis that soy food consumption may influence breast tissue activity, we examined its effect on the production of nipple aspirate fluid (NAF), a possible indicator of breast cancer risk. Of 310 premenopausal women screened, 112 (36%) produced at least 10 μL of NAF, the minimum for study participation. In a crossover design, we randomized 96 women to 2 groups who, in reverse order, consumed a high-soy diet with 2 soy servings/d (1 serving = 177 mL soy milk, 126 g tofu, or 23 g soy nuts) and a low-soy diet with <3 servings/wk of soy for 6 mo each separated by a 1-mo washout period. During each diet period, 3 NAF samples were obtained (baseline and 3 and 6 mo) using a FirstCyte Aspirator and 4 urine samples (baseline and 1, 3, and 6 mo) were analyzed for isoflavonoids by liquid chromatography tandem MS. Adherence to the study protocol according to 24-h dietary recalls and urinary isoflavonoid excretion was high. The drop-out rate was 15% (n = 14); 82 women completed the intervention. The 2 groups produced similar mean NAF volumes at baseline (P = 0.95) but differed in age and previous soy intake and in their response to the intervention (P = 0.03). In both groups, NAF volume decreased during the first 3 mo of the high-soy diet period and returned to baseline at 6 mo, but there was no effect of the high-soy diet on NAF volume (P = 0.50 for diet; P-interaction = 0.21 for diet with time). Contrary to an earlier report, soy foods in amounts consumed by Asians did not increase breast tissue activity as assessed by NAF volume.
authors.affiliation: University of Hawaii Cancer Center, Honolulu, HI 96813, USA. gertraud@crch.hawaii.edu
authors.forename: Gertraud
authors.initials: G
authors.lastname: Maskarinec
authors.forename: Yukiko
authors.initials: Y
authors.lastname: Morimoto
authors.forename: Shannon M
authors.initials: SM
authors.lastname: Conroy
authors.forename: Ian S
authors.initials: IS
authors.lastname: Pagano
authors.forename: Adrian A
authors.initials: AA
authors.lastname: Franke
mesh_terms: D000328:Adult; D018592:Cross-Over Studies; D005260:Female; D006801:Humans; D007529:Isoflavones / Q000652:urine; D008875:Middle Aged; D055966:Nipple Aspirate Fluid / Q000378:metabolism*; D017697:Premenopause; D045730:Soy Foods; D053719:Tandem Mass Spectrometry; D013997:Time Factors
chemical_list: D007529:Isoflavones