Urinary Sex Steroid Excretion Levels During a Soy Intervention Among Young Girls: A Pilot Study

Abstract

Soy intake early in life may protect against breast cancer later in life, possibly by altering sex hormone metabolism. We evaluated the feasibility of assessing urinary sex steroid excretion among 20 young girls aged 8-14 yr in an 8-wk trial. The girls consumed one daily soy serving, collected weekly overnight urine samples, and reported Tanner stages for breast and pubic hair development. Sex steroid excretion was measured in duplicate by gas chromatography-mass spectrometry and adjusted for urinary creatinine. The respective coefficients of variation for estrone, estradiol, estriol, testosterone, pregnanediol were 11.4%, 10.4%, 8.4%, 12.8%, and 4.6%. The statistical analysis included t-tests, Spearman's correlations, and analysis of variance. Seventeen girls completed the study and showed good compliance with the intervention strategy. We observed nonsignificant increases in total androgens (0.11 microg/mg creatinine) and total estrogens (0.001 microg/mg creatinine) and a nonsignificant decrease in pregnanediol (-0.03 microg/mg creatinine) during the study period. Higher Tanner stages for pubic hair development were associated with ninefold higher estrogen, fourfold higher androgen, and twofold higher pregnanediol excretions (P=0.01, P<0.001, and P=0.047, respectively). Similar differences were observed after stratification by breast development and menarcheal status. The association of sex steroid levels with pubertal development supports the validity of the sex steroid measurements.

Urinary Isoflavones Are Increased in Adults, But Decreased in Children, Consuming Soy When on Oral Antibiotic Therapy

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Vitamin D association with estradiol and progesterone in young women

“…Breast cancer is hormonally related and likely to be influenced by both estrogens and progestogens [14]. Both menstrual cycle characteristics and sex hormones have been used as outcomes to evaluate the potential roles of physical activity and phytoestrogens during adolescence [15,16]. We suggest that vitamin D may also influence female hormones in young cycling women.…”

Phytoestrogenic isoflavonoids in epidemiologic and clinical research

“…[103] This is in excellent agreement with our previous reports on healthy infants, [102] school-aged children, [104] and (pre)pubertal girls. [105] These findings suggest a higher systemic IFL exposure in children versus adults at the same body weight (BW) adjusted soy dose. When considering that growing children eat much more per kg BW, the exposure in children is probably up to twofold higher relative to adults.…”