Equol production changes over time in postmenopausal women

Franke, Adrian A.; Lai, Jennifer F.; Halm, Brunhild M.; Pagano, Ian; Kono, Naoko; Mack, Wendy J.; Hodis, Howard N.

doi:10.1016/j.jnutbio.2011.03.002

Cited by 56 publications

(69 citation statements)

References 45 publications

(70 reference statements)

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“…In a previous study with 350 post-menopausal women [81] we observed a relatively high proportion of individuals (up to 35%) who changed EQ status (either from NP to EP (IP+); or EP to NP (IP−)) over the course of 2.5 years. These EP status changes were unexpectedly not associated with antibiotic use (which can disrupt the ecological balance of resident gut bacterial [85] and thereby possibly decrease EQ production) except for selected groups when antibiotic use correlated with IP+.…”

Section: Equol Production Is Variable In Pre- and Post-menopausal Womenmentioning

confidence: 88%

Absorption, distribution, metabolism, and excretion of isoflavonoids after soy intake

Franke

Lai

Halm

2014

Archives of Biochemistry and Biophysics

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Soy is the major source of dietary exposure to isoflavonoids (IFLs). Accumulating evidence supports a role for soy and IFLs in the protection against many chronic diseases including cancer. After soy intake we found a biphasic IFL appearance pattern in plasma as well as in urine that we suggest to be due to IFL absorption in the small intestine (ca. 10%) during the first 2 h after intake and IFL absorption in the large intestine (ca. 90%) 4–6 h after intake. While each IFL disappears from the circulation at different times excellent correlations between urinary and circulating IFL values were discovered and algorithms to convert urinary excretion values into circulating levels were established. We suggest the term ‘apparent bioavailability’ when using urinary data to describe IFL exposure. The IFL bioavailability was found to be influenced by gut bacteria, oral antibiotic treatment (OABX), and an individual’s age and health status. While daidzein (DE) and genistein start to be absorbed minutes after intake, equol (EQ) appears in plasma only after a minimum of 8 h following soy intake owing to the required transit time of DE to the colon where the conversion of DE to EQ takes place by intestinal microbiota. We have also shown that the apparent IFL bioavailability is higher in children than adults, higher in healthy versus non-healthy individuals, and decreased in children but increased in adults during OABX. Finally, we propose to use a urinary EQ/DE ratio of 0.018 with a DE threshold to identify EQ producers. With this cutoff definition we observed that EQ production is inconsistent over time in 5–30% of both premenopausal and postmenopausal women.

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Section: Equol Production Is Variable In Pre- and Post-menopausal Womenmentioning

confidence: 88%

Absorption, distribution, metabolism, and excretion of isoflavonoids after soy intake

Franke

Lai

Halm

2014

Archives of Biochemistry and Biophysics

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“…More recently, Franke et al [66,67] reported different intra-individual variations during high- vs. low-soy diet [67], and using different cut-off methods and thresholds [66] for S-(−)equol producers, non-producers and those who crossed-over to either from being a producer to non-producer or vice-versa. Following antibiotic therapy, the majority of the subjects (n = 40 out of 43, or 91%) maintained their relative S-(−)equol producer or non-producer status, while one subject lost the S-(−)equol producing ability following the therapy.…”

Section: Discussionmentioning

confidence: 99%

S-(−)equol producing status not associated with breast cancer risk among low isoflavone-consuming US postmenopausal women undergoing a physician-recommended breast biopsy

et al. 2014

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Soy foods are the richest sources of isoflavones, mainly daidzein and genistein. Soy isoflavones are structurally similar to the steroid hormone 17β-estradiol and may protect against breast cancer. S-(−)equol, a metabolite of the soy isoflavone daidzein, has a higher bioavailability and greater affinity for estrogen receptor-β than daidzein. About one third of the Western population is able to produce S-(−)equol, and the ability is linked to certain gut microbes. We hypothesized that the prevalence of breast cancer, ductal hyperplasia, and overall breast pathology will be lower among S-(−)equol producing, as compared to non -producing, postmenopausal women undergoing a breast biopsy. We tested our hypothesis using a cross-sectional study design. Usual diets of the participants were supplemented with one soy bar per day for three consecutive days. Liquid chromatography-multiple reaction ion monitoring mass spectrometry analysis of urine from 143 subjects revealed 25 (17.5%) as S-(−)equol producers. We found no statistically significant associations between S-(−)equol producing status and overall breast pathology (OR 0.68; 95% CI 0.23 – 1.89), ductal hyperplasia (OR 0.84; 95% CI 0.20 – 3.41), or breast cancer (OR 0.56; 95% CI 0.16 – 1.87). However, the mean dietary isoflavones intake was much lower (0.3 mg/day) than in previous reports. Given that the amount of S-(−)equol produced in the gut depends on the amount of daidzein exposure, the low soy intake coupled with lower prevalence of S-(−)equol producing status in the study population favors towards null associations. Findings from our study could be used for further investigations on S-(−)equol producing status and disease risk.

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“…Furthermore, in our study, equol was assessed at only one time point. Although equol production has been shown to be relatively stable within individuals over time in some studies [42, 43], others have suggested that around 6 to 20% of individuals vary or crossover equol phenotypes over relatively short periods of time [44, 45]. However, the evidence to date suggests there is more often a producer to non-producer shift than vice versa [42–45].…”

Section: Discussionmentioning

confidence: 99%

Plasma equol concentration is not associated with breast cancer and fibrocystic breast conditions among women in Shanghai, China

Atkinson

Ray

et al. 2016

Nutrition Research

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Equol (a bacterial metabolite of the soy isoflavone daidzein) is produced by 30-50% of humans and may be associated with health outcomes. We hypothesized that plasma equol would be inversely associated with risks of fibrocystic breast conditions (FBC) and breast cancer (BC). Plasma from women in a breast self-examination trial in Shanghai with BC (n=269) or FBC (n=443), and age-matched controls (n=1027) was analyzed for isoflavones. Equol was grouped into categories (<20, 20-<45, and ≥45 nmol/L) and, among women with daidzein ≥20 nmol/L, the log 10 equol:daidzein ratio was grouped into tertiles. Where available, non-cancerous tissue (NCT) adjacent to the carcinomas from women with BC were classified as non-proliferative or proliferative (n=130 and 172, respectively). The lesions from women with FBC were similarly classified (n=99 and 92, respectively). Odds ratios (OR) and 95% confidence intervals (CI) were calculated across equol categories and tertiles of log 10 equol: daidzein ratio. Equol categories were not associated with FBC or BC (p>0.05). For log 10 equol:daidzein, compared to controls there were positive associations in the mid tertile for proliferative FBC (OR 2.06, 95% CI 1.08-3.93), BC with proliferative NCT (OR 2.95, 95% CI 1.37-6.35), and all BC regardless of histology (OR 2.37, 95% CI 1.43-3.95). However, trends in ORs with increasing plasma equol values or equol: daidzein ratios were not observed (p>0.05). The results of this study do not provide evidence that

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Equol production changes over time in postmenopausal women

Cited by 56 publications

References 45 publications

Absorption, distribution, metabolism, and excretion of isoflavonoids after soy intake

Absorption, distribution, metabolism, and excretion of isoflavonoids after soy intake

S-(−)equol producing status not associated with breast cancer risk among low isoflavone-consuming US postmenopausal women undergoing a physician-recommended breast biopsy

Plasma equol concentration is not associated with breast cancer and fibrocystic breast conditions among women in Shanghai, China

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