Dietary soy and tea combinations for prevention of breast and prostate cancers by targeting metabolic syndrome elements in mice

Abstract

Background: The prevalence of metabolic syndrome is high and is increasing in parallel with increasing incidences of breast and prostate cancers. The combination of soy with tea was shown to have synergistic effects on preventing breast and prostate tumors, but the effects of soy and tea combinations on metabolic syndrome-related elements have not been investigated.

Objective: We aimed to determine the effects of soy and tea components, alone and in combination, on abdominal adipose mass and serum concentrations of adipokines, growth factors, and sex hormones in male and female mice.

Design: Male and female FVB/N mice were treated with soy, tea components, or both. Food intake and body weight were monitored weekly. At the end of the experiment, abdominal white adipose tissue was weighed, and serum concentrations of biomarkers were measured.

Results: Whole teas, but not the tea polyphenol extracts, significantly reduced abdominal white adipose tissue by 43-60% in female mice and by 65-70% in male mice. The combination of soy phytochemical concentrate and green tea reduced serum insulin-like growth factor-I concentrations in both male and female mice in a synergistic manner. The soy phytochemical concentrate and tea combinations reduced serum estrogen concentrations in female mice in a synergistic manner. Soy phytochemical concentrate and teas also significantly reduced serum leptin concentrations in both male and female mice and testosterone concentrations in male mice.

Conclusion: Further research is warranted to investigate whether soy and tea combinations may prevent breast or prostate cancer in a synergistic manner in part by alleviating metabolic disorders.

FIGURE 1

Effects of soy phytochemical concentrate (SPC) and tea combinations on serum concentrations of insulin, leptin, insulin-like growth factor-I (IGF-I), adiponectin, adiponectin corrected for white adipose tissue (WAT), and testosterone in male mice. C, control; BT, black tea; GT, green tea. Values are x̄ ± SEM, n = 12/group, and were analyzed by ANOVA followed by Tukey’s test. Within each panel, the value with a letter is significantly different from the control: ^aP < 0.05, ^bP < 0.005, ^cP < 0.0005.

FIGURE 2

Effects of soy phytochemical concentrate (SPC) and tea combinations on serum concentrations of insulin, leptin, insulin-like growth factor-I (IGF-I), adiponectin, adiponectin corrected for white adipose tissue (WAT), and estradiol (E2) in female mice. C, control; BT, black tea; GT, green tea. Values are x̄ ± SEM, n = 12/group, and were analyzed by ANOVA followed by Tukey’s test. Within each panel, the value with a letter is significantly different from the control: ^aP < 0.05, ^cP < 0.0005.