Dietary Isoflavones May Protect against Prostate Cancer in Japanese Men ,

Nagata, Yasunobu; Sonoda, Tomoko; Mori, Mitsuru; Miyanaga, Naoto; Okumura, Koji; Goto, Ken; Naito, Seiji; Fujimoto, Kiyohide; Hirao, Yoshihiko; Takahashi, Atsushi; Tsukamoto, Taiji; Akaza, Hideyuki

doi:10.1093/jn/137.8.1974

Cited by 96 publications

(79 citation statements)

References 36 publications

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“…In earlier observational studies, dietary intake of isoflavones or soy product consumption was inversely associated with prostate cancer risk in some (Severson et al, 1989;Jacobsen et al, 1998;Strom et al, 1999;Kolonel et al, 2000a;Lee et al, 2003;Sonoda et al, 2004;Hedelin et al, 2006a;Heald et al, 2007;Kurahashi et al, 2007;Nagata et al, 2007), but not all reports (Sung et al, 1999;Villeneuve Matching for geographic location (Hawaii or California), race/ethnicity, birth year ( ± 1 year), date ( ± 6 months) and time ( ± 2 h) of specimen collection, and fasting hours (0 -o6, 6 -o8, 8 -o10, and 10+ h). The models were adjusted for age at specimen collection and fasting hours as continuous variables, as well as family history of prostate cancer, BMI, and education.…”

Section: Discussionmentioning

confidence: 98%

Urinary phytoestrogen excretion and prostate cancer risk: a nested case–control study in the Multiethnic Cohort

et al. 2009

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BACKGROUND: Phytoestrogens are of special interest in prostate cancer research because populations in Asia with a high consumption of phytoestrogens have a lower incidence of the disease than comparable populations in Western countries. METHODS: This case -control study is nested within a large multiethnic cohort in Hawaii and California. Urine samples were analysed for daidzein, genistein, equol, and enterolactone among 249 incident prostate cancer cases and 404 controls matched on age, race/ ethnicity, date/time of specimen collection, and fasting status. RESULTS: The median excretion of daidzein was 0.173 nmol mg À1 creatinine in cases and 0.291 in controls (P ¼ 0.01), and the median excretion of genistein was 0.048 in cases and 0.078 in controls (P ¼ 0.05). An inverse association was seen for daidzein overall (odds ratio for the highest vs lowest quintile ¼ 0.55, 95% confidence interval ¼ 0.31 -0.98, P trend ¼ 0.03) and seemed to apply to localized (P trend ¼ 0.08) as well as advanced or high-grade cancer (P trend ¼ 0.09). This association was consistent across the four ethnic groups examined. Although the relationship was weaker for genistein, the odds ratios and trends were similarly inverse. Urinary excretion of equol and enterolactone was not significantly related to prostate cancer risk. CONCLUSION: Our findings suggest that high intake of isoflavones, as reflected by urinary excretion of daidzein and genistein, may be protective against prostate cancer.

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Section: Discussionmentioning

confidence: 98%

Urinary phytoestrogen excretion and prostate cancer risk: a nested case–control study in the Multiethnic Cohort

et al. 2009

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“…Isoflavones are one of the phytoestrogens that are possible preventive factors in several hormone-dependent cancers such as prostate cancer and breast cancer (Zhu et al, 2011;Khan et al, 2012 ), cardiovascular disease (Wong et al, 2012;Usui et al, 2013), menopausal symptoms (Aso et al, 2012;Jenks et al, 2012), and osteoporosis (Scheiber et al, 2001;Tousen et al, 2011). Especially, genistein and daidzein, which are aglycones of isoflavones, were found to have potential roles in the prevention of prostate cancer (Akaza et al, 2004;Nagata et al, 2007;Gardner et al, 2009).…”

Section: Introductionmentioning

confidence: 99%

Counts of Slackia sp. strain NATTS in Intestinal Flora are Correlated to Serum Concentrations of Equol both in Prostate Cancer Cases and Controls in Japanese Men

Sugiyama¹,

Nagata²,

Fukuta³

et al. 2014

Asian Pacific Journal of Cancer Prevention

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Background: Isoflavones, which are included in soybeans, have been suggested to protect against prostate cancer. Equol, one of isoflavones, is an intestinally derived bacterial metabolite of daidzein. A newly identified equol-producing bacterium, Slackia sp. strain NATTS, with a high equol-producing activity was isolated from human feces in Japanese adults. Counts of Slackia sp. strain NATTS in intestinal flora have not been assessed with regard to prostate cancer risk. In this study, we investigated the association of serum isoflavones and counts of Slackia sp. strain NATTS with prostate cancer risk in a case-control study. Materials and Methods: Concentrations of isoflavones and counts of Slackia sp. strain NATTS in feces were measured from 44 patients with prostate cancer and 28 hospital controls. The risk of prostate cancer was evaluated in terms of odds ratios (ORs) and 95% confidence intervals (CIs) by the logistic regression analysis. Results: The detection proportions of Slackia sp. strain NATTS in cases and controls were 34.1% and 25.0%, respectively. Counts of Slackia sp. strain NATTS were significantly correlated with serum concentrations of equol both in cases and controls (Spearman correlation coefficients, r s =0.639 and r s =0.572, p<0.01, respectively). Serum concentrations of genistein, daidzein, glycitein, and equol were not significantly associated with risk of prostate cancer. Conclusions: This study found that counts of Slackia sp. strain NATTS correlated with serum concentrations of equol both in prostate cancer cases and controls, but serum isoflavone concentrations were not associated with risk of prostate cancer in our patients.

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“…These polyphenolic compounds bind to estrogen receptors alpha and beta, with a preference for the latter [4]. Several epidemiological studies have suggested that high phytoestrogen levels are associated with a reduced risk of hormone-sensitive diseases [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Levels of urinary isoflavones and lignan polyphenols in Japanese women

Liu

Tanabe

Harada

2013

Environ Health Prev Med

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Objectives High consumption of soybean products has been associated with a reduced risk of hormone-sensitive tumors. Soybean products contain phytoestrogens, such as daidzein, and sesame seeds contain secoisolariciresinol. These compounds are further metabolized to equol, enterodiol, and enterolactone by intestinal bacteria. However, individual differences in the metabolizing potential remain unclear. The aim of this study was to evaluate the urinary daidzein, equol, enterodiol, and enterolactone concentrations in women from several different regions of Japan according to age group. Methods Five hundred urine samples collected from Japanese women living in Sapporo, Sendai, Kyoto, Kochi, and Naha were analyzed for daidzein, equol, enterodiol, and enterolactone concentration by gas chromatographymass spectrometry. Results The urinary isoflavone and lignan polyphenol levels did not differ significantly among the sampling sites, except for daidzein, which was highest in urine collected at Naha. The prevalence of equol producers was 39 % in the total study cohort. In equol producers, a positive correlation was observed between the urinary daidzein and equol levels (r = 0.399, p \ 0.001). However, there was no significant difference between daidzein concentrations in equol producers and non-producers. Moreover, the levels of enterodiol and enterolactone were higher in equol producers than in equol non-producers. In the multivariate logistic analyses, two factors, Sendai dwelling and current smoking, were found to be significant [equol producers to non-producers: odds ratio 2.15 (95 % confidence interval: 1.17-4.02) and odds ratio 0.32 (0.15-0.63), respectively]. Conclusions Our data suggest that geographic factors and smoking status should be considered during the evaluation of equol in urine samples and that the same pathway may be responsible for the metabolism of both isoflavones and lignan polyphenols.

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Dietary Isoflavones May Protect against Prostate Cancer in Japanese Men ,

Cited by 96 publications

References 36 publications

Urinary phytoestrogen excretion and prostate cancer risk: a nested case–control study in the Multiethnic Cohort

Urinary phytoestrogen excretion and prostate cancer risk: a nested case–control study in the Multiethnic Cohort

Counts of Slackia sp. strain NATTS in Intestinal Flora are Correlated to Serum Concentrations of Equol both in Prostate Cancer Cases and Controls in Japanese Men

Levels of urinary isoflavones and lignan polyphenols in Japanese women

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