A prospective study of dietary flavonoid intake and incidence of epithelial ovarian cancer

Abstract

Flavonoids are antioxidant compounds found in plants, including fruits, vegetables and tea. No prior prospective studies have examined the association between intake of flavonoids in the flavonol and flavone subclasses and ovarian cancer risk. We analyzed the association between intake of 5 common dietary flavonoids and incidence of epithelial ovarian cancer among 66,940 women in the Nurses' Health Study. We calculated each participant's intake of myricetin, kaempferol, quercetin, luteolin and apigenin from dietary data collected at multiple time points, and used Cox proportional hazards regression to model the incidence rate ratio (RR) of ovarian cancer for each quintile of intake. Our analysis included 347 cases diagnosed between 1984 and 2002, and 950,347 personyears of follow-up. There was no clear association between total intake of the 5 flavonoids examined and incidence of ovarian cancer (RR 5 0.75 for the highest versus lowest quintile, 95% confidence interval [CI] 5 0.51-1.09). However, there was a significant 40% decrease in ovarian cancer incidence for the highest versus lowest quintile of kaempferol intake (RR 5 0.60, 95% CI 5 0.42-0.87; p-trend 5 0.002), and a significant 34% decrease in incidence for the highest versus lowest quintile of luteolin intake (RR 5 0.66, 95% CI 5 0.49-0.91; p-trend 5 0.01). There was evidence of an inverse association with consumption of tea (nonherbal) and broccoli, the primary contributors to kaempferol intake in our population. These data suggest that dietary intake of certain flavonoids may reduce ovarian cancer risk, although additional prospective studies are needed to further evaluate this association. If confirmed, these results would provide an important target for ovarian cancer prevention. ' 2007 Wiley-Liss, Inc.Key words: flavonoids; flavonols; flavones; diet; ovarian cancer There are few lifestyle factors known to reduce ovarian cancer risk, and no dietary exposure, with the possible exception of lactose, 1 has been clearly associated with risk. Flavonoids are polyphenol chemicals found naturally in fruits, vegetables, tea and other plant-derived foods and beverages. Experimental evidence suggests that flavonoids have several potential anticarcinogenic characteristics, including antioxidant, antiestrogenic, antiproliferative and antiinflammatory properties. [2][3][4][5] Flavonoids are defined by their chemical structure, which includes 2 aromatic rings (the ''A'' and ''B'' rings) linked by a three-carbon bridge that comprises part of a third six-member ''C'' ring. 6 There are over 5,000 individual flavonoid compounds and at least 10 subclasses of flavonoids, which are characterized further by the structure of the C ring and the connection of the B and C rings. 2,6,7 Flavonoids from 6 of these subclasses-flavones, flavonols, flavanols (catechins), flavanones, isoflavones and anthocyanidins-are common in the human diet. 2,7 Three studies have previously evaluated the association between dietary flavonoid intake and ovarian cancer risk. [8][9][10] However, only...

Luteolin inhibits invasion of prostate cancer PC3 cells through E-cadherin

“…Another case-control study in Scotland showed that there is a strong and linear inverse associations of flavonoids intake with colorectal cancer risk (45). A recent study showed that there was a significant decrease in incidence of ovarian cancer for the highest versus lowest quintile of luteolin intake (46).…”

Tea and coffee drinking and ovarian cancer risk: results from the Netherlands Cohort Study and a meta-analysis

“…A random effects model was used because of significant heterogeneity. On tea drinking and ovarian cancer, eight casecontrol studies (Byers et al, 1983;Miller et al, 1987;La Vecchia et al, 1992;Kuper et al, 2000;Tavani et al, 2001;Zhang et al, 2002;Jordan et al, 2004;Baker et al, 2007) and, including this study, five cohort studies (Zheng et al, 1996;Larsson and Wolk, 2005b;Gates et al, 2007;Silvera et al, 2007) have been conducted. Coffee drinking and ovarian cancer risk was investigated in 16 case-control studies (Trichopoulos et al, 1981;Hartge et al, 1982;Byers et al, 1983;Cramer et al, 1984;La Vecchia et al, 1984;Tzonou et al, 1984;Miller et al, 1987;Whittemore et al, 1988;Polychronopoulou et al, 1993;Kuper et al, 2000;Tavani et al, 2001;Jordan et al, 2004;Riman et al, 2004;Baker et al, 2007) and, including this study, five cohort studies (Snowdon and Phillips, 1984;Stensvold and Jacobsen, 1994;Larsson and Wolk, 2005a;Silvera et al, 2007).…”

An In Vivo Antilymphatic Screen in Zebrafish Identifies Novel Inhibitors of Mammalian Lymphangiogenesis and Lymphatic-Mediated Metastasis

“…Regardless, these results suggest that antilymphatics may be best given in conjunction with other compounds that prevent tumor growth. Previous work has shown that kaempferol consumption has been associated with reduced risk of developing many cancers (38)(39)(40) and has also been shown to reduce VEGF expression in human cancer cell lines (41,42). To our knowledge, this study is the first to report VEGFR inhibition and antilymphatic activity for kaempferol.…”