Genistein, daidzein, and their .beta.-glycoside conjugates: antitumor isoflavones in soybean foods from American and Asian diets

Coward, Lori; Barnes, Neil; Setchell, Kenneth D.R.; Barnes, Stephen

doi:10.1021/jf00035a027

Cited by 805 publications

(459 citation statements)

References 20 publications

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“…The total isoflavone concentration of the diet we used is similar to that reported in a separate study (approximately 350 mg/g diet of total isoflavones) that was found to have estrogenic activity in rodents [16]. We have compared the influence of this commercial diet to that of a custom diet with very low concentrations of phytoestrogens (Ziegler Brothers, Gardner, PA, USA) [24,105]. This custom diet is referred to, hereafter, as the Phyto-free diet.…”

Section: Phytoestrogen Dietsmentioning

confidence: 67%

“…The estrogenic potency of naturally occurring soy phytoestrogens is significant, and if concentrations are high, these compounds have the potential to trigger many of the biological responses evoked by endogenous steroidal estrogens [18,101,104]. Notably, rather than use a diet that contains only one or a combination of a few phytoestrogens (such as genistein and/or daidzein), throughout our studies, we utilized a commercially available diet (Harlan Teklad 8604, Madison, WI, USA) which was found by highperformance liquid chromatography to contain [24,105] approximately 600 mg/g total phytoestrogens (in the glycoside form), being equivalent to approximately 420 mg/g diet of the aglycones (or total isoflavones). This diet is referred to as the Phyto-rich diet.…”

Section: Phytoestrogen Dietsmentioning

confidence: 99%

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Neurobehavioral effects of dietary soy phytoestrogens

Lephart

West

Weber

et al. 2002

Neurotoxicology and Teratology

189

117

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Section: Phytoestrogen Dietsmentioning

confidence: 67%

Section: Phytoestrogen Dietsmentioning

confidence: 99%

Neurobehavioral effects of dietary soy phytoestrogens

Lephart

West

Weber

et al. 2002

Neurotoxicology and Teratology

189

117

View full text Add to dashboard Cite

“…Subjects were instructed to consume 161 g of Mori-Nu Silken Extra Firm tofu or 322 g of Eden soymilk or 75 g of Kimbo frozen soybean peas per day; these amounts of the three foods contained equivalent amounts of isoflavones. On the basis of published soy food isoflavone levels (Coward et al, 1993), subjects were permitted to consume any combination of the three foods that provided an equivalent amount of isoflavone. The soy diet commenced on day 1 of the third menstrual cycle and ended on day 1 of the sixth menstrual cycle.…”

Section: Study Subjects and Data Collectionmentioning

confidence: 99%

Effects of soy foods on ovarian function in premenopausal women

Stanczyk

Hendrich

et al. 2000

Br J Cancer

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It has been proposed that the high intake of soy foods among Asians may partly explain their lower rates of breast cancer, perhaps by lowering endogenous oestrogen levels, although this has been inadequately studied. Twenty healthy cycling premenopausal women (ten Asians and ten non-Asians) participated in a 7-month soy intervention study which was designed to investigate the effect of supplementation on ovarian function. Asian soy foods (tofu, soymilk, green soybean peas) in the amount of approximately 32 mg of isoflavones per day were added to the women's diets for three menstrual cycles. The women's baseline (two cycles) serum hormone levels were compared to levels during soy intervention (three cycles) and levels after intervention (two cycles). During the entire study period, subjects provided almost daily overnight urine samples and blood specimens during specified days of their menstrual cycles. The day of urinary luteinizing hormone (LH) peak was used as a marker for the day of ovulation. Knowledge of day of ovulation allowed comparison of hormone measurements at baseline to those obtained during intervention and recovery cycles with standardization of day of cycle. Soy intervention was associated with a statistically significant reduction in serum luteal oestradiol level (–9.3%, P < 0.05), but there were no significant changes in follicular phase oestradiol, follicular or luteal phase progesterone, sex hormone-binding globulin or menstrual cycle length. This significant reduction in luteal phase oestradiol was, however, observed only among Asian (–17.4%) but not among non-Asian (–1.2%) participants; urinary excretion of isoflavones was higher among Asians than non-Asians (29.2 vs 17.1 μmol day −1 , P = 0.16) during the intervention period. Thus, supplementation using traditional soy foods reduced serum oestradiol levels among Asian participants in this study. Differences in the type of soy products (i.e. traditional soy foods versus soy protein products), amount of isoflavones, and race/ethnicity of participants may have contributed to the divergent results. Larger soy intervention studies designed specifically to include participants of different race/ethnicities and using both traditional soy foods and soy protein products providing comparable doses of isoflavones are needed to definitively determine the effect of soy on ovarian function. © 2000 Cancer Research Campaign

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“…Soy foods were proposed as one of the possible sources of protection (Ziegler et al, 1993;Yan and Spitznagel, 2004) owing to their estrogenic and anti-estrogenic properties (Adlercreutz, 1995). Most soy foods contain glycosides of the isoflavones daidzein, genistein and glycitein, which are hydrolyzed by intestinal glucosidases and absorbed as aglycones following ingestion (Coward et al, 1993;Wang and Murphy, 1994;Tsukamoto et al, 1995;Franke et al, 1998Franke et al, , 2004. The isoflavone daidzein is metabolized to equol and O-desmethylangolensin by intestinal bacteria (Axelson et al, 1984;Atkinson et al, 2004).…”

Section: Introductionmentioning

confidence: 99%

Urinary isoflavonoid excretion and soy consumption in three generations of Japanese women in Hawaii

et al. 2006

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Objective: To explore soy intake and urinary isoflavonoid excretion within several generations of American-Japanese women based on the hypothesis that earlier generations excrete higher levels of urinary isoflavonoids, in particular the metabolite equol, than later generations. Subjects: A convenience sample of 43 women from 19 families aged 18-78 years, all of whom reported at least 50% Japanese ancestry. Interventions: Each woman collected overnight urine samples at baseline and after consuming one serving of soymilk, both samples were analyzed for the isoflavonoids daidzein, genistein and equol using liquid chromatography-mass spectrometry. Results: Median isoflavone intakes during the last year were 7.2 mg/day for the first generation, 7.3 mg/day for the second generation and 6.3 mg/day for the third generation (P ¼ 0.36). At baseline, the median isoflavonoid excretion for the first generation was nonsignificantly higher than for later generations (190, 86 and 42 nmol/h; P ¼ 0.20) but after intervention, the median urinary isoflavonoid excretion was very similar for the three groups: 2465, 1895 and 2775 nmol/h (P ¼ 0.70). Following intervention, a nonsignificantly higher proportion of older than younger women (53 vs 32 and 33%; P ¼ 0.41) excreted the metabolite equol. The respective median equol excretion rates by generation following intervention were 39.5, 4.2 and 3.5 nmol/h (P ¼ 0.04). Conclusions: This small investigation among three generations of Japanese-Americans detected a higher equol production among older women after a soy challenge, but no difference in the excretion of total isoflavonoids after a standardized dose of soymilk was observed.

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Genistein, daidzein, and their .beta.-glycoside conjugates: antitumor isoflavones in soybean foods from American and Asian diets

Cited by 805 publications

References 20 publications

Neurobehavioral effects of dietary soy phytoestrogens

Neurobehavioral effects of dietary soy phytoestrogens

Effects of soy foods on ovarian function in premenopausal women

Urinary isoflavonoid excretion and soy consumption in three generations of Japanese women in Hawaii

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