Isoflavones in Retail and Institutional Soy Foods

Murphy, Patricia A.; Song, Tongtong; Buseman, Gwen; Barua, Kobita; Beecher, Gary R.; Trainer, Denise; Holden, Joanne M.

doi:10.1021/jf981144o

Cited by 302 publications

(230 citation statements)

References 17 publications

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“…The higher values initially reported appear to have been based on the assumption that soy foods contain 2-3 mg of isoflavones per gram, when these levels apply primarily to whole soybeans, a form of soy food not very commonly consumed in Asia (Adlercreutz et al, 1991;Nagata et al, 1998;Chen et al, 1999;Wakai et al, 1999). Recent studies Murphy et al, 1999) confirmed that commonly consumed Asian soy foods (e.g. soymilk, tofu, miso) contain substantially lower isoflavone levels (0.10-0.35 mg g -1 ) than whole soybeans; these values also tend to be lower than previously published values.…”

Section: Discussionmentioning

confidence: 99%

“…soymilk, tofu, miso) contain substantially lower isoflavone levels (0.10-0.35 mg g -1 ) than whole soybeans; these values also tend to be lower than previously published values. Failure to normalize for molecular weight differences of the isoflavone isomers Murphy et al, 1999) and inadequate accounting for moisture factor may explain in part higher isoflavone values. The average amount of isoflavones (32.0 mg day -1 ) consumed by participants in our study during the intervention period is within the range of current isoflavone intake in Asia (Nagata et al, 1998;Chen et al, 1999;Wakai et al, 1999).…”

Section: Discussionmentioning

confidence: 99%

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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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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Effects of soy foods on ovarian function in premenopausal women

Stanczyk

Hendrich

et al. 2000

Br J Cancer

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“…The bulk of the dietary dosage of phytoestrogens is attributed to two major phytoestrogen classes: isoflavones and lignans. The most significant sources of isoflavones are soybean and soy products (Table 1), especially fermented soy products (Reinli and Block, 1996;Coward et al, 1998;Murphy et al, 1999). Lignans are primarily found in oilseeds such as flaxseed (Table 1), and in lesser amounts in whole legumes, whole grain cereals, vegetables, and fruits .…”

Section: Introductionmentioning

confidence: 99%

“…Phytoestrogens may be present in the human diet in substantial amounts (Irvine et al, 1998;Murphy et al, 1999) (Table 1). Estimated consumption of phytoestrogen-rich foods by a multiethnic population in California was 12-28 servings per month (Horn-Ross et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

Urinary phytoestrogen concentrations in the U.S. population (1999–2000)

Valentín-Blasini

Sadowski

Walden

et al. 2005

J Expo Sci Environ Epidemiol

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We report population-based urinary concentrations of phytoestrogens stratified by age, sex, and composite racial/ethnic variables. We measured the isoflavones F genistein, daidzein, equol, and O-desmethylangolensin (O-DMA) F and the lignans F enterolactone and enterodiol F in approximately 2500 urine samples from individuals aged 6 years and older who participated in the National Health and Nutrition Examination Survey (NHANES) in 1999 and 2000. We detected all phytoestrogens in over 70% of the samples analyzed; enterolactone was detected in the highest concentrations, and daidzein was detected with the highest frequency. The geometric means for each phytoestrogen were as follows: genistein, 22.3 mg/g; daidzein, 68.6 mg/g; equol, 7.65 mg/g; O-DMA, 3.95 mg/g; enterolactone, 217 mg/g; and enterodiol, 24.3 mg/g creatinine. The 95th percentiles for each phytoestrogen were as follows: genistein, 380 mg/g; daidzein, 944 mg/g; equol, 50.3 mg/g; O-DMA, 217 mg/g; enterolactone, 2240 mg/g; and enterodiol, 240 mg/g creatinine. Multivariate analyses showed statistically significant differences among many of the demographic subgroups. Adolescents had higher concentrations of genistein and equol than adults. Non-Hispanic whites had higher concentrations of enterodiol and equol than Mexican Americans or non-Hispanic blacks. Non-Hispanic whites also had higher concentrations of enterolactone and O-DMA than Mexican Americans. Mexican Americans had higher concentrations of genistein than non-Hispanic blacks; however, the opposite was found for O-DMA. Determination of phytoestrogen exposure in the US population will help us to better understand phytoestrogen consumption in the US and will assist us in elucidating the potential role of phytoestrogens in protecting against cancer and heart disease.

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“…Cependant, plusieurs de ces résultats font l'objet de controverses et quelques auteurs ont souligné l'absence d'études complètes de toxicité des PO, sans lesquelles il ne peut être établi de réelle analyse risques/bénéfices de tels composés pour l'homme. Les niveaux mesurés dans le lait de soja peuvent dépasser 200 mg/l [31] et plusieurs préparations à base de soja atteignent des teneurs supérieures à 500 mg/kg [32]. Ces aliments conduisent à des ingestions quotidiennes qui sont de l'ordre de 30 à 50 mg d'isoflavones, c'est-à-dire identiques à celles des préparations préconisées chez les femmes ménopausées.…”

Section: Phyto-oestrogènesunclassified