Quantification of isoflavones and lignans in serum using isotope dilution liquid chromatography/tandem mass spectrometry

Grace, Philip B.; Taylor, James I.; Botting, Nigel P.; Fryatt, Tara; Oldfield, Mark F.; Al‐Maharik, Nawaf; Bingham, Sheila

doi:10.1002/rcm.1059

Cited by 78 publications

(95 citation statements)

References 64 publications

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“…The strengths of the present study include the breadth of data available for controlling potential confounders, and its prospective design, thus avoiding bias among cases for their biomarker samples and questionnaire on dietary and questions on health behavior. The mass spectrometry quantification method for samples used in EPIC-Norfolk offers specificity and sensitivity that is greater than that provided by time-resolved fluoroimmunoassay, the method commonly applied in prior phytoestrogen biomarker research (24).…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Lack of Prospective Associations between Plasma and Urinary Phytoestrogens and Risk of Prostate or Colorectal Cancer in the European Prospective into Cancer-Norfolk Study

Ward¹,

Chapelais

Kuhnle

et al. 2008

Cancer Epidemiology, Biomarkers &Amp; Prevention

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Section: Discussionmentioning

confidence: 99%

“…Intrabatch and interbatch coefficient of variation (%) were <4% except for glycitein (5.6%) and equol (5.7%; ref. 24). Details on case-control frequency matching, quality assurance, and methodology have been published elsewhere (22,24,25).…”

Section: Methodsmentioning

confidence: 99%

Lack of Prospective Associations between Plasma and Urinary Phytoestrogens and Risk of Prostate or Colorectal Cancer in the European Prospective into Cancer-Norfolk Study

Ward¹,

Chapelais

Kuhnle

et al. 2008

Cancer Epidemiology, Biomarkers &Amp; Prevention

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“…Measurements of plasma concentrations of genistein, daidzein, glycitein and equol We measured the plasma concentrations of the isoflavones genistein, daidzein, glycitein and equol, a daidzein metabolite, using liquid chromatography and MS, which allow precise, sensitive and rapid analysis with limited volumes of plasma [18].…”

Section: Methodsmentioning

confidence: 99%

Plasma isoflavone concentration is associated with decreased risk of type 2 diabetes in Korean women but not men: results from the Korean Genome and Epidemiology Study

Kim

Ahn

et al. 2014

Diabetologia

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Aims/hypothesis To examine the association between soybean products and risk of type 2 diabetes, we measured four isoflavone biological markers-genistein, daidzein, glycitein and equol-in a nested case-control study. Methods The study population was composed of 693 cases (316 women and 377 men) and 698 matched controls (317 women and 381 men) within the Korean Genome and Epidemiology Study. The concentrations of isoflavone biomarkers were measured using HPLC-MS/MS on plasma samples that were collected at baseline. A stratified analysis was undertaken to examine the association between plasma isoflavone concentrations and risk of type 2 diabetes according to sex and equol production. Logistic regression models were used to compute ORs and 95% CIs adjusted for confounders. ResultsIn women, compared with the lowest quartile of plasma concentration of genistein, the highest quartile exhibited a significantly decreased risk of diabetes (OR 0.58, 95% CI 0.35, 0.95). When stratified by equol-producing status in women, the OR for diabetes in the highest vs the lowest quartile of genistein concentration was 0.31 (95% CI 0.16, 0.60) in equol producers, but genistein concentration was not associated with risk of diabetes in equol non-producers (p for interaction=0.013). In men, isoflavone concentrations were not associated with risk of diabetes, regardless of equolproducing status. Conclusions/interpretation High plasma concentrations of genistein were associated with a decreased risk of type 2 diabetes in women. This inverse association was prominent in equol-producing participants. These results suggest a beneficial effect of a high intake of soybean products on risk of type 2 diabetes in women.

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“…The samples were prepared, and equol was measured per Grace et al (2003). There was a patent binomial distribution in equol concentrations (Supplementary Figure 1), and the estimated limit of detection (LOD) was 0.068 lg/L.…”

Section: Serum Equol Measurementmentioning

confidence: 99%

Epidemiological profiles between equol producers and nonproducers: a genomewide association study of the equol-producing phenotype

Hong

Ahn

et al. 2012

Genes Nutr

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Equol is a daidzein (a phytoestrogen isoflavone) metabolite of gut bacteria, and the ability to produce equol varies between individuals and reduces the risks of several diseases. We tested the effects of equol production on health in Koreans and identified the genetic factors that determine the equol-producing phenotype. In 1391 subjects, the equol-producing phenotype was determined, based on measurements of serum equol concentrations. The anthropometric and blood biochemical measurements between equol producers and nonproducers were analyzed by LC-MS/MS. Genetic factors were identified in a genomewide association study (GWAS), and the interaction between genetic factors and the equol-producing phenotype was examined. We observed that 70.1 % of the study population produced equol. Blood pressure was significantly lower in equol producers (beta ± SE = -1.35 ± 0.67, p = 0.045). In our genomewide association study, we identified 5 single-nucleotide polymorphisms (p \ 1 9 10 -5 ) in HACE1. The most significant SNP was rs6927608, and individuals with a minor allele of rs6927608 did not produce equol (odds ratio = 0.57 (95 % CI 0.45-0.72), p value = 2.5 9 10 -6 ). Notably, the interaction between equol production and the rs6927608 HACE1 SNP was significantly associated with systolic blood pressure (p value = 1.3 9 10 4 ). Equol production is linked to blood pressure, and HACE1, identified in our (GWAS), might be a determinant of the equol-producing phenotype.

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Quantification of isoflavones and lignans in serum using isotope dilution liquid chromatography/tandem mass spectrometry

Cited by 78 publications

References 64 publications

Lack of Prospective Associations between Plasma and Urinary Phytoestrogens and Risk of Prostate or Colorectal Cancer in the European Prospective into Cancer-Norfolk Study

Lack of Prospective Associations between Plasma and Urinary Phytoestrogens and Risk of Prostate or Colorectal Cancer in the European Prospective into Cancer-Norfolk Study

Plasma isoflavone concentration is associated with decreased risk of type 2 diabetes in Korean women but not men: results from the Korean Genome and Epidemiology Study

Epidemiological profiles between equol producers and nonproducers: a genomewide association study of the equol-producing phenotype

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