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Published on: June 7, 2020
Effects of soybean glyceollins and estradiol in postmenopausal female monkeys
Charles E Wood1, Thomas B Clarkson, Susan E Appt
1Department of Pathology/Section on Comparative Medicine, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA. chwood@wfubmc.edu
Abstract:
Glyceollins are a novel class of soybean phytoalexins with potential cancer-protective antiestrogenic effects. The purpose of this study was to evaluate the estrogen-antagonist effects of glyceollin-enriched soy protein on biomarkers for breast cancer risk. Thirty female postmenopausal cynomolgus macaques were randomized to one of three dietary treatments for 3 wk: 1) estradiol (E2, 1 mg/day) + casein/lactalbumin (control); 2) E2 + soy protein isolate (SPI) containing 194 mg/day isoflavonoids; and 3) E2 + glyceollin-enriched soy protein (GLY) containing 189 mg/day isoflavonoids + 134 mg/day glyceollins. Doses are expressed in calorically scaled human equivalents. Mean serum glyceollin concentrations at 4 h postfeeding were 134.2 +/- 34.6 nmol/L in the GLY group and negligible in the SPI group (P = 0.0007). Breast proliferation was significantly increased in the control group (+237%, P = 0.01) but not in the SPI group (+198%, P = 0.08) or GLY group (+36%, P = 0.18). Gene expression of trefoil factor 1 and progesterone receptor, two markers of estrogen receptor activity in breast epithelium, were also significantly higher in the control (P < 0.05 for both) but not in the GLY group. These preliminary findings suggest that soybean glyceollins are natural compounds with potential estrogen-modulating properties in the breast.
Insights
Soybean glyceollins show potential estrogen-modulating effects. This study found glyceollin-enriched soy protein reduced breast proliferation and estrogen receptor activity markers in macaques, suggesting cancer-protective properties.
Area of Science:
- Phytoestrogens and Nutrigenomics
- Cancer Prevention Research
- Endocrinology
Background:
- Glyceollins, novel soybean phytoalexins, exhibit potential antiestrogenic and cancer-protective effects.
- Understanding the impact of soy compounds on breast cancer risk biomarkers is crucial.
Purpose of the Study:
- To evaluate the estrogen-antagonist effects of glyceollin-enriched soy protein on breast cancer risk biomarkers.
- To compare the effects of glyceollin-enriched soy protein versus standard soy protein isolate.
Main Methods:
- Thirty postmenopausal cynomolgus macaques were assigned to diets with estradiol plus control, soy protein isolate (SPI), or glyceollin-enriched soy protein (GLY).
- Serum glyceollin concentrations, breast proliferation, and gene expression of trefoil factor 1 and progesterone receptor were measured.
Main Results:
- Significant breast proliferation was observed in the control group but not in the SPI or GLY groups.
- Gene expression of estrogen receptor activity markers (trefoil factor 1, progesterone receptor) increased in the control group but not in the GLY group.
- Serum glyceollin concentrations were significantly higher in the GLY group compared to the SPI group.
Conclusions:
- Soybean glyceollins possess estrogen-modulating properties in breast tissue.
- Glyceollin-enriched soy protein may offer a protective effect against estrogen-driven breast changes.
- These findings support further investigation into glyceollins for breast cancer risk reduction.
