Rapid HPLC Analysis of Dietary Phytoestrogens from Legumes and from Human Urine

Franke, Adrian A.; Custer, Laurie J.; Cerna, Carmencita M.; Narala, Kavitha

doi:10.3181/00379727-208-43826

Cited by 262 publications

(149 citation statements)

References 0 publications

Supporting

Mentioning

140

Contrasting

Unclassified

Order By: Relevance

“…Using [ 3 H]estradiol-glucuronate (New England Nuclear Medicine, USA), the extent of deconjugation by b-glucuronidase was estimated to be 9373% (4). Urinary isoflavones were analysed by HPLC as described by Franke et al (1995) with the following modifications. Isoflavones were extracted from urine using a solid-phase C-18 extraction cartridge (Alltech, Baulkham Hills, NSW, Australia) activated with 5 ml of methanol and 5 ml water.…”

Section: Analysis Of Urinary Isoflavonoidsmentioning

confidence: 99%

Urinary isoflavonoid excretion is inversely associated with the ratio of protein to dietary fibre intake in young women

et al. 2004

View full text Add to dashboard Cite

Objective: To examine the prevalence of excretion of urinary isoflavonoids in women and determine any relationships with accustomed macronutrient intake. Design: Volunteers in one of two 4-month studies. Study 1 was a randomised crossover study whereby subjects consumed a placebo or isoflavone supplement for 2 months and crossed over. Study 2 was a parallel design in which subjects consumed a placebo for 1 month and an isoflavone supplement for 3 months. Setting: All subjects were free-living, healthy volunteers. Subjects: A total of 25 (study 1, n ¼ 14; study 2, n ¼ 11) premenopausal women were recruited through advertisements. Interventions: Volunteers were supplemented for 2 months (study 1) or 3 months (study 2) with purified isoflavones (86 mg/ day) derived from red clover. Urinary isoflavonoids were measured during the placebo and the second month of isoflavone treatment. Macronutrient intakes were determined from weighed food records. Results: During isoflavone supplementation, the concentration of urinary total isoflavonoids increased by 15-fold (Po0.0001), with 5.4-fold variation between individuals. Multiple linear regression analysis showed that 24% of this variation could be explained by an interaction between dietary fibre and protein (P ¼ 0.047), with a highly significant inverse association between total isoflavonoid concentration and the protein to fibre ratio (r ¼ À0.51, P ¼ 0.009). Conclusions: Supplementation with purified isoflavones results in an increase in urinary isoflavonoid excretion and part of the individual variation in response is associated with an interaction between intakes of protein and dietary fibre. Whether manipulation of these macronutrients could enhance efficacy of isoflavone supplements remains to be determined.

show abstract

Section: Analysis Of Urinary Isoflavonoidsmentioning

confidence: 99%

Urinary isoflavonoid excretion is inversely associated with the ratio of protein to dietary fibre intake in young women

et al. 2004

View full text Add to dashboard Cite

show abstract

“…Because isoflavones are predominantly specific to soy foods and are excreted in urine within 24-36 h of consumption (Franke et al, 1995(Franke et al, , 1998bSetchell et al, 2003), urinary assessment of isoflavones is considered a biomarker for soy intake (Maskarinec et al, 1998). At baseline and for the subsequent 8 weeks, the girls collected their first morning urine on the most convenient weekend day in a 15 ml Compliance with soy among girls G Maskarinec et al cryovial.…”

Section: Compliance Measuresmentioning

confidence: 99%

Urinary isoflavone excretion as a compliance measure in a soy intervention among young girls: a pilot study

et al. 2004

View full text Add to dashboard Cite

Objective: To investigate the compliance of young girls with a soy intervention. Design: An 8-week dietary intervention and urine sample collection. Setting: Free-living girls. Subjects: A convenience sample of 8-to 14-y-old girls (20 started and 17 finished the study) recruited through flyers distributed to staff members and previous study participants. Intervention: The girls consumed one daily serving of soymilk, soy nuts, or tofu, completed 3-day food records, kept daily soy intake logs, and collected weekly urine samples. Main outcome measures: Compliance with the intervention was evaluated by daily soy intake logs, 3-day food records analyzed by the center's Food Composition and Food Groups Servings Databases, and weekly urinary isoflavone excretion using high-pressure liquid chromatography. The statistical analysis included paired t-tests, analysis of variance, and Spearman's rankorder correlation coefficients. Results: Daily soy intake logs indicated a mean intake of 6.28 servings out of a maximum of 7.0 servings per week. The food records revealed a six-fold increase in isoflavone intake during the study period (Po0.01) which was confirmed by an increase in urinary isoflavone excretion of similar magnitude (23.3-142.1 nmol/mg creatinine, P ¼ 0.02). Conclusions: This study demonstrated the ability of young girls to consume one daily soy serving and the usefulness of urinary isoflavones as a primary compliance measure. The high urinary isoflavone excretion levels detected in girls as compared to adult women suggest less intestinal degradation and/or greater absorption of isoflavones in nonadult populations. This finding requires further investigations into the pharmacokinetics of isoflavones.

show abstract

“…Inappropriate or excessive exposure may be harmful, depending upon the timing and relative levels of the alpha and beta estrogen receptors, coactivators and corepressors present in the cell (Davis et al, 1999). For example, phytoestrogen exposure during hormone-mediated life stages, Franke et al, 1995;Reinli and Block, 1996;Lampe 2003 such as adolescence or pregnancy, may alter the normal hormone functions during that period. This is an area of much current focus and debate.…”

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

View full text Add to dashboard Cite

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.

show abstract

Rapid HPLC Analysis of Dietary Phytoestrogens from Legumes and from Human Urine

Cited by 262 publications

References 0 publications

Urinary isoflavonoid excretion is inversely associated with the ratio of protein to dietary fibre intake in young women

Urinary isoflavonoid excretion is inversely associated with the ratio of protein to dietary fibre intake in young women

Urinary isoflavone excretion as a compliance measure in a soy intervention among young girls: a pilot study

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

Contact Info

Product

Resources

About