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Effects of tomato and soy on serum adipokine concentrations in postmenopausal women at increased breast cancer risk: a cross-over dietary intervention trial.

February 12, 2014

Division of Population Sciences (A.A.L., J.L.K., C.R.D., E.D.P.), and Divisions of Biostatistics (J.P., M.L.P.) and Epidemiology (E.D.P.), College of Public Health, and Division of Cancer Prevention and Control (E.D.P.), College of Medicine, Ohio State University Comprehensive Cancer Center, The Ohio State University Columbus, Ohio 43210; Department of Epidemiology (A.A.L.), School of Public Health, Rutgers University, Piscataway, New Jersey 08854; Rutgers Cancer Institute of New Jersey (A.A.L.), New Brunswick, New Jersey 08903; and Department of Public Health Sciences (M.Z.V.), Wake Forest School of Medicine, Winston-Salem, North Carolina 27157.

Llanos AA1, Peng J, Pennell ML, Krok JL, Vitolins MZ, Degraffinreid CR, Paskett ED.




Breast cancer risk among postmenopausal women increases as body mass index increases. Practical preventive methods to reduce risk of breast cancer are lacking. Few studies have investigated the effects of carotenoids and isoflavones on circulating adipokines in postmenopausal women.


The aim was to examine the effects of lycopene- and isoflavone-rich diets on serum adipokines.


This was a 26-week, two-arm, longitudinal crossover trial.


Participants were recruited from clinics at The Ohio State University Comprehensive Cancer Center.


Seventy postmenopausal women at increased breast cancer risk participated in the study. The mean age and body mass index of participants was 57.2 years and 30.0 kg/m(2), respectively; the study was comprised of 81.4% whites.


The interventions included 10 weeks of consumption of a tomato-based diet (≥25 mg lycopene daily) and 10 weeks of consumption of a soy-based diet (≥40 g of soy protein daily), with a 2-week washout in between.


Changes in serum adiponectin, leptin, and the adiponectin to leptin ratio were examined for each intervention through linear mixed models, with ratio estimates corresponding to postintervention adipokine concentrations relative to preintervention concentrations.


After the tomato intervention, among all women, adiponectin concentration increased (ratio 1.09, 95% confidence interval (CI) 1.00-1.18), with a stronger effect observed among nonobese women (ratio 1.13, 95% CI 1.02-1.25). After the soy intervention, adiponectin decreased overall (ratio 0.91, 95% CI 0.84-0.97), with a larger reduction observed among nonobese women (ratio 0.89, 95% CI 0.81-0.98). Overall, no significant changes in leptin or the adiponectin to leptin ratio were observed after either intervention.


Increasing dietary consumption of tomato-based foods may beneficially increase serum adiponectin concentrations among postmenopausal women at increased breast cancer risk, especially those who are not obese. Additional studies are essential to confirm these effects and to elucidate the specific mechanisms that may make phytonutrients found in tomatoes practical as breast cancer chemopreventive agents.