A Novel Tomato-Soy Juice Induces a Dose-Response Increase in Urinary and Plasma Phytochemical Biomarkers in Men with Prostate Cancer. Issue 1 (24th November 2018)

• Record Type: Journal Article
• Authors: Grainger, Elizabeth M; Moran, Nancy E; Francis, David M; Schwartz, Steven J; Wan, Lei; Thomas-Ahner, Jennifer; Kopec, Rachel E; Riedl, Ken M; Young, Gregory S; Abaza, Ronney; Bahnson, Robert R; Clinton, Steven K
• Is Part Of: Journal of nutrition. Volume 149:Issue 1(2019)
• Page Start: 26
• Page End: 35
• Publication Date: 2018-11-24
• Subjects: carotenoids -- lycopene -- isoflavones -- tomato -- soy -- prostate cancer; Nutrition -- Periodicals; Diet -- Periodicals; 613.205
• DOI: 10.1093/jn/nxy232
• Languages: English
• ISSNs: 0022-3166

Abstract

ABSTRACT: Background: Tomato and soy intake is associated with reduced prostate cancer risk or severity in epidemiologic and experimental studies. Objective: On the basis of the principle that multiple bioactives in tomato and soy may act on diverse anticancer pathways, we developed and characterized a tomato-soy juice for clinical trials. In this phase 2 dose-escalating study, we examined plasma, prostate, and urine biomarkers of carotenoid and isoflavone exposure. Methods: Men scheduled for prostatectomy were recruited to consume 0, 1, or 2 cans of tomato-soy juice/d before surgery (mean ± SD duration: 24 ± 4.6 d). The juice provided 20.6 mg lycopene and 66 mg isoflavone aglycone equivalents/177-mL can. Plasma carotenoids and urinary isoflavone metabolites were quantified by HPLC–photometric diode array and prostate carotenoids and isoflavones by HPLC–tandem mass spectrometry. Results: We documented significant dose-response increases ( P < 0.05) in plasma concentrations of tomato carotenoids. Plasma concentrations were 1.86-, 1.69-, 1.73-, and 1.69-fold higher for lycopene, β-carotene, phytoene, and phytofluene, respectively, for the 1-can/d group and 2.34-, 3.43-, 2.54-, and 2.29-fold higher, respectively, for the 2-cans/d group compared with 0 cans/d. Urinary isoflavones daidzein, genistein, and glycitein increased in a dose-dependent manner. Prostate carotenoid and isoflavone concentrations were not dose-dependent in this short intervention; yet, correlations between plasma carotenoid and urinary isoflavones with respective prostate concentrations were documented ( R 2 = 0.78 for lycopene, P < 0.001; R 2 = 0.59 for dihydrodaidzein, P < 0.001). Secondary clustering analyses showed urinary isoflavone metabolite phenotypes. To our knowledge, this is the first demonstration of the phytoene and phytofluene in prostate tissue after a dietary intervention. Secondary analysis showed that the 2-cans/d group experienced a nonsignificant decrease in prostate-specific antigen slope compared with 0 cans/d ( P = 0.078). Conclusion: These findings provide the foundation for evaluating a well-characterized tomato-soy juice in human clinical trials to define the impact on human prostate carcinogenesis. This trial is registered at clinicaltrials.gov as NCT01009736.