Isoflavone Intake Research Articles

Inverse association between isoflavones and prediabetes risk: evidence from NHANES 2007-2010 and 2017-2018.

Prediabetes is a metabolic condition characterized by blood glucose levels that are higher than normal but do not meet the threshold for a diabetes diagnosis. Individuals with prediabetes are at an increased risk of developing type 2 diabetes and associated complications. However, limited epidemiological studies have investigated the association between flavonoids from plant-based diets and the risk of prediabetes, and the existing evidence from these studies is inconsistent. Therefore, we utilized data from 19,021 participants (mean age: 32.03 years) in the National Health and Nutrition Examination Survey (NHANES) conducted during 2007-2010 and 2017-2018 to investigate the potential association between dietary flavonoid intake and prediabetes risk by weighted logistic regression analysis. Furthermore, the data from 3,706 participants (mean age: 35.98 years) from NHANES 2007-2010 were used to assess the correlation between concentrations of isoflavones and their metabolites in urine and prediabetes risk by weighted logistic regression analysis. Our findings revealed an inverse association between the intake of glycitein (OR: 0.88; 95% CI: 0.82-0.96; p = 0.003), genistein (OR: 0.98; 95% CI: 0.97-0.99; p = 0.004), daidzein (OR: 0.98; 95% CI: 0.96-0.99; p = 0.009), and total isoflavones (OR: 0.99; 95% CI: 0.98-1.00; p = 0.005) with the risk of prediabetes. Moreover, we observed an inverse association between the concentration of daidzein in urine (OR: 0.84; 95% CI: 0.73-0.96; p = 0.012) and the concentration of genistein in urine (OR:0.83; 95% CI: 0.75-0.93; p = 0.003) with the risk of prediabetes using weighted logistic regression. In conclusion, our findings suggest a potential protective effect of isoflavones against the development of prediabetes.

Skeletal Effects of Soy Isoflavone in Humans: Bone Mineral Density and Bone Markers

The potential skeletal effects of soy isoflavones in humans have garnered significant interest owing to their structural resemblance to endogenous estrogen and their potential to impact bone health. This abstract provides a concise overview of the current understanding of the effects of soy isoflavones on bone mineral density (BMD) and bone markers. Numerous studies have investigated the relationship between soy isoflavone consumption and BMD. Some studies have suggested a positive association between soy isoflavone intake and BMD, particularly among postmenopausal women. Isoflavones may exert their effects through estrogen receptor-mediated pathways, potentially mitigating bone loss by reducing osteoclastic activity and promoting osteoblastic functions. However, conflicting results have been reported, with certain studies demonstrating no significant impact on BMD. In addition to BMD, bone markers such as serum osteocalcin, urinary deoxypyridinoline, and tartrate-resistant acid phosphatase have been evaluated to elucidate the mechanistic effects of soy isoflavones on bone metabolism. These markers provide insights into bone turnover, resorption, and formation. Clinical trials have reported mixed findings regarding the influence of soy isoflavones on bone markers, reflecting the complexity of their interaction with bone physiology

Isoflavone intake and depressive symptoms among workers

Background & AimHigh intake of isoflavones has been reported to be associated with decreased prevalence of depressive symptoms. However, no prospective study has examined this association. We prospectively investigated the association between isoflavone intake and depressive symptoms in a Japanese working population. MethodsParticipants were 1162 workers (1033 men and 129 women aged 18-68 years) without depressive symptoms at baseline. Dietary intake was assessed using a validated self-administered diet history questionnaire. Depressive symptoms were assessed using the Center for Epidemiologic Studies Depression (CES-D) scale. Cox proportional hazards regression for interval-censored data was used to estimate the hazard ratio of depressive symptoms (CES-D ≥16) according to the tertile of isoflavone intake with adjustment for covariates. ResultsDuring 5065 person-years of follow-up, 276 (23.8%) workers were newly identified as having depressive symptoms. Isoflavone intake was not associated with risk of depressive symptoms. After adjustment for lifestyle and dietary factors and baseline CES-D score, the multivariable-adjusted hazard ratios (95% confidence interval) for the lowest through highest tertile of isoflavone intake were 1.00 (reference), 0.93 (0.66-1.31), and 0.93 (0.62-1.38) (P for trend = 0.70). ConclusionsOur findings suggest that higher isoflavone intake is not associated with decreased risk of depressive symptoms among Japanese.

The Inverse Association Between Isoflavone Intake and Prevalence of Metabolic Syndrome: A Cross-Sectional Study from National Health and Nutrition Examination Survey.

Objective: Metabolic syndrome (MetS) is a global disease burden that has resulted in 10 million people being affected by it, yet no new drugs have been approved for clinical treatment. Isoflavone may be able to stop the development of MetS or enhance its treatment. Therefore, we investigated the relationship between dietary intake of isoflavone and prevalence of MetS to find potentially effective treatments. Methods: We conducted a cross-sectional study using data from 8512 National Health and Nutrition Examination Survey (NHANES) participants from 2007 to 2010 and 2017 to 2018 and their associated isoflavone intake from the flavonoid database in the USDA Food and Nutrient Database for Dietary Studies (FNDDS). We investigated the relationship between MetS status and isoflavone intake by adjusting for confounding variables using multivariable logistic regression models. Results: In a multivariable-adjusted model, there was a negative association between isoflavone intake and the incidence of MetS (odds ratio for Q4 vs. Q1 was 0.66, 95% confidence interval = 0.51-0.86, P = 0.003, p for trend was <0.001). This inverse association remained robust across most subgroups, while nonsignificant interactions were tested between isoflavone intake and age, sex, ethnicity, economic status, body mass index, smoking status, alcohol consumption, and physical activity level (P values for interaction >0.05). Conclusions: We found that MetS prevalence decreased with increased isoflavone intake, suggesting that dietary patterns of soy food or supplement consumption may be a valuable strategy to reduce the disease burden and the prevalence of MetS.

Association between ultra-processed food and flavonoid intakes in a nationally representative sample of the US population.

Consumption of ultra-processed food (UPF) has been associated with several chronic diseases and poor diet quality. It is reasonable to speculate that the consumption of UPF negatively associates with flavonoid dietary intake; however, this assumption has not been previously examined. The present study aims to assess association between the dietary contribution of UPF and flavonoid intake in the US population aged 0 years and above. We performed a cross-sectional analysis of dietary data collected by 24-h recalls from 7640 participants participating in the National Health and Nutrition Examination Survey 2017-2018. Foods were classified according to the Nova classification system. The updated US Department of Agriculture (USDA) Database for the Flavonoid Content of Selected Foods (Release 3.3) database was used to estimate total and six classes of flavonoid intakes. Flavonoid intakes were compared across quintiles of dietary contribution of UPF (% of total energy intake) using linear regression models. The total and five out of six class flavonoid intakes decreased between 50 and 70 % across extreme quintiles of the dietary contribution of UPF (Pfor linear trend < 0·001); only isoflavones increased by over 260 %. Our findings suggest that consumption of UPF is associated with lower total and five of six class flavonoid intakes and with higher isoflavone intakes, supporting previous evidence of the negative impact of UPF consumption on the overall quality of the diet and health outcomes.

Dietary Isoflavone Intake and Breast Cancer Prognosis: A Prospective Analysis and Meta-Analysis

We aimed to examine the association between dietary isoflavone intake and the risk of breast cancer recurrence and summarize evidence on the role of dietary isoflavone intake in breast cancer prognosis. This prospective study included 592 breast cancer survivors who completed a dietary assessment. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazards models. Of the studies published until May 31, 2023, that were searched in PUBMED and EMBASE databases, 14 studies were selected. Adjusted HRs were combined using fixed- or random-effects models. During the median follow-up of 4.3 years, 47 recurrences were identified. The HR (95% CI) for recurrence comparing the highest versus the lowest tertile of isoflavones intake was 1.29 (0.60–2.78). In a meta-analysis of previously published data and ours, dietary isoflavone intake was associated with a better breast cancer prognosis. The combined HRs (95% CIs) comparing the extreme categories were 0.81 (0.67–0.98) for recurrence and 0.85 (0.76–0.96) for all-cause mortality. A nonlinear inverse association was observed between isoflavone intake and the risk of recurrence and all-cause mortality. Our study suggests that dietary isoflavone intake is associated with a favorable prognosis in breast cancer survivors and warrants further investigation.

Use of Fermented Red Clover Isoflavones in the Treatment of Overactive Bladder in Postmenopausal Women: A Randomized, Double-Blinded, Placebo-Controlled Trial.

Postmenopausal women are at risk of developing an overactive bladder (OAB). Conventional vaginal estrogen has shown promise for symptom relief. Isoflavones have proven effective as an alternative to estrogen treatment against menopause-related symptoms. However, its effect on OAB symptoms has not been studied. This study investigates if fermented red clover isoflavones reduce OAB symptoms in postmenopausal women. In this randomized, double-blinded, placebo-controlled trial, women were administered red clover extract (RCE) or a placebo twice daily for three months. Women filled out the International Consultation on Incontinence Questionnaire Overactive Bladder (ICIQ-OAB) and Urinary Incontinence Short Form (ICIQ-UI-SF), together with a fluid intake and voiding diary. A total of 33 women (16 in the RCE group and 17 in the placebo group) were included in the analysis. Baseline demographics and OAB characteristics were comparable across groups. Intake of RCE did not lead to significant relief in most urinary bladder symptom measures, although a significant reduction in the bother of urinary urgency (p = 0.033) and a tendency towards a decreased ICIQ-OAB score were observed (p = 0.056). In contrast, the placebo exhibited a significant decrease in the ICIQ-OAB score (p = 0.021) and in some diary outcomes. We found that an intake of isoflavones did not relieve OAB symptoms in postmenopausal women.

Phytochemicals and Glioma: Results from Dietary Mixed Exposure

The information about phytochemicals’ potential to prevent cancer is encouraging, including for glioma. However, most studies on phytochemicals and glioma mainly focused on preclinical studies. Their epidemiological studies were not sufficient, and the evidence on the dose–response relationship is usually limited. Therefore, this investigation examined the association between dietary phytochemical intake and glioma in Chinese adults. This case–control study was carried out in a hospital in China. Based on the dietary information obtained from the food frequency questionnaire, the researchers estimated the phytochemical intake of 506 patients with glioma and 506 controls. Compared with participants in the lowest tertile, the highest intakes of carotene, flavonoids, soy isoflavones, anthocyanin, and resveratrol were associated with a reduced risk of glioma. The WQS and BKMR models suggested that anthocyanin and carotene have a greater influence on glioma. The significant nonlinear dose–response associations between dietary phytochemicals and glioma were suggested using the restricted cubic spline function. According to this study on phytochemicals and glioma, higher intakes of carotene, flavonoids, soy isoflavones, anthocyanins, and resveratrol are linked to a lower risk of glioma. So, we might not be able to ignore how phytochemicals affect gliomas.

Isoflavone Consumption and Risk of Breast Cancer: An Updated Systematic Review with Meta-Analysis of Observational Studies.

Epidemiological studies that focus on the relationship between dietary isoflavone intake and the risk of breast cancer still lead to inconsistent conclusions. Herein, we conducted a meta-analysis of the latest studies to explore this issue. We performed a systematic search using Web of Science, PubMed, and Embase from inception to August 2021. The robust error meta-regression (REMR) model and generalized least squares trend (GLST) model were used to establish dose-response relationships between isoflavones and breast cancer risk. Seven cohort studies and 17 case-control studies were included in the meta-analysis, and the summary OR for breast cancer was 0.71 (95% CI 0.72-0.81) when comparing the highest to the lowest isoflavone intake. A subgroup analysis further showed that neither menopausal status nor ER status has a significant influence on the association between isoflavone intake and breast cancer risk, while the isoflavone intake doses and study design does. When the isoflavones exposure was less than 10 mg/day, no effects on breast cancer risk were detected. The inverse association was significant in the case-control studies but not in the cohort studies. In the dose-response meta-analysis of the cohort studies, we observed an inverse association between isoflavone intake and breast cancer: a 10 mg/day increase in isoflavone intake was related to reductions of 6.8% (OR = 0.932, 95% CI 0.90-0.96) and 3.2% (OR = 0.968, 95% CI 0.94-0.99) in breast cancer risk when using REMR and GLST, respectively. In the dose-response meta-analysis of the case-control studies, the inverse association for every 10 mg/day isoflavone intake was associated with breast cancer risk reductions by 11.7%. present evidence demonstrated that taking in dietary isoflavone is helpful in reducing the breast cancer risk.

Abstract 6468: Association of food groups and dietary pattern with breast cancer risk: A systematic review and meta-analysis

Abstract We conducted a systematic review and meta-analysis of current evidence for the association between food groups, dietary patterns, and breast cancer risk among the Asian population. This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. We performed a systematic literature search up to November 2022 in English in the PubMed, Web of Science, Embase, and Cochrane databases. Risk ratios (RRs) with 95% confidence intervals (CIs) were extracted as effect sizes. Publication bias was estimated by the funnel plot method. We collected the data from 15 cohort studies and 30 case-control studies meeting the search criteria. The meta-analysis found that fruit and vegetable consumption was associated with a 27% and 35% lower risk of breast cancer, respectively [RR = 0.73 (0.56, 0.96); RR = 0.65 (0.47, 0.90)]. By contrast, no significance was found between meat, soy food, and green tea consumption and breast cancer risk (P &amp;gt; 0.05). However, soy protein and isoflavone intake could lower breast cancer risk by 35% and 32%, respectively [RR = 0.65 (0.51, 0.83); RR = 0.68 (0.55, 0.82)]. As for dietary pattern, higher adherence to a healthy dietary pattern and healthy eating index was associated with a 38% and 62% reduction in breast cancer risk, respectively [RR = 0.62 (0.44, 0.88; RR = 0.38 (0.22, 0.67)], while high adherence to an unhealthy dietary pattern was associated with a 44% increased risk [RR = 1.44 (1.06, 1.96)]. Considering alcohol consumption, a 75% increased risk of breast cancer was found [RR= 1.75 (1.33, 2.30)]. The present meta-analysis found that high intakes of fruit, vegetable, soy protein, and soy isoflavone significantly reduced the risk of breast cancer, while high intake of alcohol had a significantly increased risk. Meat, soy food, and green tea consumption were not significantly associated with breast cancer risk. Considering dietary patterns, higher adherence to a healthy eating index and a healthy dietary pattern may reduce breast cancer risk. Conversely, adherence to unhealthy dietary patterns may increase breast cancer risk. However, further studies are needed to confirm the associations between dietary patterns and breast cancer in the Asian population. This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No.2022R1F1A1074279). MSIT: Ministry of Science and ICT. Citation Format: Jialei Fu, Woo-Kyoung Shin, Dan Huang, Sukhong Min, Li-Juan Tan, Hyein Jung, Khongorzul Ganbat, Jiwon Jeong, Seok-Jae Oh, Bayarmaa Nasan Ulzii, Daehee Kang, Sangah Shin. Association of food groups and dietary pattern with breast cancer risk: A systematic review and meta-analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6468.

Intake of soy products and soy isoflavones in relation to ovarian reserve

To investigate the association between intake of soy food and isoflavone with ovarian reserve. Previous studies suggest on the relationship between soy intake and human fertility are inconsistent. Some clinical studies suggest that soy and phytoestrogens may not be deleterious to reproduction and may even be beneficial in couples undergoing infertility treatment. However, no studies have evaluated the relationship between soy or isoflavone intake with markers of ovarian reserve other than follicle-stimulating hormone (FSH). Cross-sectional study. An academic fertility center. Patients presenting to an academic fertility center between 2007 and 2019 were invited to participate in the Environment and Reproductive Health Study. Six hundred and sixty seven participants reported their soy food intake and had an antral follicle count (AFC) assessment. Intake of 15 soy-based foods during the previous 3 months was obtained at baseline and intake of isoflavone was estimated. Participants were divided into 5 groups based on soy food and isoflavone intake considering those who did not consume soy as the reference group. Ovarian reserve was assessed using AFC as the primary outcome measure, with antimüllerian hormone (AMH) and FSH as secondary outcome measures. The AFC was measured on the third day of the menstrual cycle. Moreover, FSH and AMH levels were measured in blood samples obtained on the third day and the follicular phase of the menstrual cycle. To evaluate the association between soy intake and ovarian reserve, we used Poisson regression models for AFC and quantile regression models for AMH and day 3 FSH levels by adjusting for confounders. Participants had a median age of 35.0 years. The median intake of soy was 0.09 servings/day and isoflavones was 1.78 mg/day. Moreover, AFC, AMH, and FSH were unrelated to soy intake in crude analyses. We found no association between soy food intake with AFC or day 3 FSH level in multivariable models. However, participants in the highest category of soy food intake had significantly low AMH levels (-1.16, 95% confidence interval: -1.92, -0.41). Soy intake had no association with AFC, AMH, or FSH in sensitivity analyses that included using different cutoff points of soy intake, excluding participants in the highest 2.5 percentile of intake, and additional statistical adjustment for dietary patterns. The results of this study are not consistent with a strong positive or inverse association of soy or isoflavone intakes within the observed range of intake, which substantially overlaps with that in the general population of the United States as well as the ovarian reserve among individuals presenting to fertility centers.

Abstract P2-06-02: A randomized controlled trial of soy isoflavone intake on mammographic density among Malaysian women

Abstract Introduction: Soy intake is associated with lower breast cancer risk in observational studies of Asian women, but clinical trials of soy isoflavone (ISF) supplements report no effect on biomarkers of breast cancer risk among Caucasian women. To date, there are no such trials among Asian women living in Asia. We conducted a three-armed, randomized controlled trial (RCT) to assess the effects of one-year intervention of soy isoflavone supplements (100mg/day) or soy isoflavones through diet (50mg/day) on mammographic density (MD) change among peri- and postmenopausal Malaysian women. Methodology: Healthy women between 45-65 years old were enrolled between November 2018 and December 2019 at a private tertiary hospital in Malaysia. Women were randomly assigned into the 100mg/day ISF Supplement arm, 50mg/day ISF Diet arm, or Control arm. Dense area was assessed from digital mammograms conducted at enrolment and after 12 months. We compared absolute and relative change in dense area over the study period by study arm using Kruskal Wallis tests. Results: Of the 118 women who received the intervention, 91 women completed the study whilst 27 women (23%) were lost to follow up. After 12 months of intervention, women in the ISF Supplement arm observed a marginally larger decline in dense area (-1.3cm2), compared to women in the ISF Diet arm (-0.5cm2) and Control arm (-0.8cm2), but this difference was not statistically significant (p=0.479). Notably, these effects appear to be stronger and limited to women who enrolled within 5 years of menopause, where up to 6cm2 decline in MD was observed in the ISF Supplement arm, compared to &amp;lt; 1.0cm in the Control arm (p=0.131). Conclusion: This RCT demonstrates a possible causal association between soy ISF intake and lower breast cancer risk among Asian women, specifically around the time of menopause, but these findings will require confirmation in a larger trial. Citation Format: Nadia Rajaram, Beverley Yap, Mikael Eriksson, Shivaani Mariapun, Lee Mei Tan, Hamizah Saat, Evelyn Ho, Nur Aishah Mohd Taib, Geok Lin Khor, Cheng Har Yip, Weang Kee Ho, Per Hall, Soo Hwang Teo. A randomized controlled trial of soy isoflavone intake on mammographic density among Malaysian women [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P2-06-02.

Flavonoid intake is associated with lower all-cause and disease-specific mortality: The National Health and Nutrition Examination Survey 2007-2010 and 2017-2018.

Adequate intake of flavonoids may influence mortality, particularly of heart and cerebrovascular diseases. However, the importance of each flavonoid and its subclasses in preventing all-cause and disease-specific mortalities remain unclear. In addition, it is unknown which population groups would benefit from high flavonoid intake. Therefore, personalized mortality risk based on flavonoid intake needs to be estimated. The association between flavonoid intake and mortality among 14,029 participants in the National Health and Nutrition Examination Survey was examined using Cox proportional hazards analysis. A prognostic risk score and nomogram linking flavonoid intake and mortality were constructed. During a median follow-up of 117 months (9.75 years), 1,603 incident deaths were confirmed. Total flavonol intake was associated with a significantly reduced all-cause mortality [multivariable adjusted hazard ratio [HR] (95% confidence interval [CI]), 0.87 (0.81, 0.94), p for trend <0.001], especially in participants aged 50 years and older and former smokers. Similarly, total anthocyanidin intake was inversely associated with all-cause mortality [0.91 (0.84, 0.99), p for trend = 0.03], which was most significant in non-alcoholics. The intake of isoflavones was negatively associated with all-cause mortality [0.81 (0.70, 0.94), p = 0.01]. Moreover, a risk score was constructed based on survival-related flavonoid intake. The constructed nomogram accurately predicted the all-cause mortality of individuals based on flavonoid intake. Taken together, our results can be used to improve personalized nutrition.

Association of food groups and dietary pattern with breast cancer risk: A systematic review and meta-analysis

We conducted a systematic review and meta-analysis of current evidence for the association between food groups, dietary patterns, and breast cancer risk among the Asian population. This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. We performed a systematic literature search up to December 2022 in English in the PubMed, Web of Science, Embase, and Cochrane databases. Risk ratios (RRs) with 95% confidence intervals (CIs) were extracted as effect sizes. Publication bias was estimated by two different funnel plot methods. We collected the data from 15 cohort studies and 34 case-control studies meeting the search criteria. The meta-analysis found that the consumption of fruits and, likewise, vegetables were associated with a 29% lower risk of breast cancer, respectively [RR=0.71 (0.55, 0.93); RR=0.71 (0.53, 0.95)]. By contrast, no significance was found between meat, soy foods, and green tea consumption and breast cancer risk (P>0.05). However, soy protein and isoflavone intake could lower breast cancer risk by 35% and 32%, respectively [RR=0.65 (0.51, 0.83); RR=0.68 (0.55, 0.82)]. As for the dietary pattern, high adherence to a healthy dietary pattern and, similarly, to a healthy eating index was associated with a 38% and 51% reduction in breast cancer risk, respectively [RR=0.62 (0.44, 0.88; RR=0.49 (0.27, 0.87)], while high adherence to an unhealthy dietary pattern was associated with a 44% increased risk [RR=1.44 (1.06, 1.96)]. Considering alcohol consumption, a 75% increased risk of breast cancer was found [RR=1.75 (1.33, 2.30)]. The present meta-analysis found that high intakes of fruits, vegetables, soy protein, and soy isoflavone significantly reduced the risk of breast cancer, while high intake of alcohol had a significantly increased risk. Meat, soy food, and green tea consumption were not significantly associated with breast cancer risk. Considering dietary patterns, high adherence to a healthy eating index and a healthy dietary pattern may reduce breast cancer risk. Conversely, adherence to unhealthy dietary patterns may increase breast cancer risk. However, further studies are needed to confirm the associations between dietary patterns and breast cancer in the Asian population.

Dietary phytoestrogens and total and cause-specific mortality: results from 2 prospective cohort studies

BackgroundEvidence regarding dietary phytoestrogens in relation to mortality remains limited. ObjectivesThe objective of the study is to examine the associations of intake of isoflavones, lignans, and coumarins with total and cause-specific mortality in US males and females. MethodsWe followed 75,981 females in the Nurses’ Health Study (1984–2018) and 44,001 males in the Health Professionals Follow-up Study (1986–2018), who were free of cardiovascular disease (CVD), diabetes, or cancer at baseline. Their diet was repeatedly assessed using validated food frequency questionnaires every 2–4 y. Associations with mortality were assessed using time-dependent Cox models with adjustments for demographics, dietary and lifestyle factors, and medical history. ResultsDuring 3,427,156 person-years of follow-up, we documented 50,734 deaths, including 12,492 CVD deaths, 13,726 cancer deaths, and 24,516 other non-CVD and noncancer deaths. After multivariable adjustment, the higher total phytoestrogen intake was associated with lower risk of total CVD and other non-CVD and noncancer mortality: comparing extreme quintiles, the pooled HRs (95% CIs) were 0.89 (0.87, 0.92), 0.90 (0.85, 0.96), and 0.86 (0.82, 0.90), respectively. We did not find a significant association with cancer mortality [0.97 (0.92, 1.03)]. For individual phytoestrogens in relation to total mortality, the pooled HRs (95% CIs) comparing extreme quintiles were 0.90 (0.87, 0.92) for isoflavones, 0.93 (0.90, 0.96) for lignans, and 0.93 (0.90, 0.95) for coumarins. Individual phytoestrogens were also significantly associated with lower risk of CVD mortality and other types of mortality. Primary food sources of phytoestrogens, including tofu, soy milk, whole grains, tea, and flaxseed, were also inversely associated with total mortality. ConclusionsA higher intake of total phytoestrogens, including isoflavones, lignans, and coumarins, and foods rich in these compounds was associated with lower risk of total and certain cause-specific mortality in generally healthy US adults. These data suggest that these phytochemicals and their dietary sources may be integrated into an overall healthy diet to achieve a longer life span.

Phytoestrogens and Breast Cancer: Should French Recommendations Evolve?

Breast cancer (BC) occurs less frequently in Asia, where there is high soy consumption. It has been hypothesized that soy isoflavones could be protective against BC recurrence and mortality. At the same time, health organizations in several countries have differing recommendations for soy consumption (soy foods or dietary supplements) in BC survivors. The objective of this review is to analyze the literature and to determine whether it is justified to advise avoiding soy in dietary supplements and/or food in women with a history of BC. We conducted a systematic literature search with the Medline/Pubmed and Web of Science databases. Only prospective cohort studies published since 2009 were retained. The endpoint of studies was BC recurrence and/or mortality, and the association with soy isoflavone intake was specifically targeted. Seven studies were included. None of these studies found statistically significant adverse effects of soy consumption on BC recurrence or mortality (specific or all-cause). Overall, only one study was not able to find beneficial effects of soy intake on BC patients. The other studies concluded that there were positive associations but in very variable ways. Two studies found a decrease in BC recurrence associated with a higher isoflavone intake only for post-menopausal women. The other four studies concluded that there were positive associations regardless of menopausal status. Four studies showed better results on women with hormonal-sensitive cancer and/or patients receiving hormonal treatment. Only one found a stronger association for patients with ER-negative BC. No adverse effects of soy isoflavones on BC mortality/recurrence were found. Soy isoflavones may exert beneficial effects. These results coincide with other recent works and suggest that soy isoflavone intake is safe for BC survivors. Thus, these data no longer seem to coincide with the French recommendations, which could then be brought to evolve. However, in order to confirm the current results, larger studies are needed.

Association between flavonoid and subclasses intake and metabolic associated fatty liver disease in U.S. adults: Results from National Health and Nutrition Examination Survey 2017-2018.

Metabolic associated fatty liver disease (MAFLD) formerly known as non-alcoholic fatty liver disease (NAFLD) is the most common chronic liver disease. Flavonoid is considered a promising candidate for metabolic disease prevention although few studies have explored the relationship between flavonoid intake and MAFLD. To assess the relationship between flavonoid intake and MAFLD prevalence in the U.S. adult population. The data of this cross-sectional study was obtained from National Health and Nutrition Examination Survey (NHANES) and Food and Nutrient Database for Dietary Studies (FNDDS) 2017-2018. Flavonoid and subclasses intake was assessed by two 24h recalls. MAFLD was diagnosed according to the consensus definitions. Multivariate logistic regression model was performed to examine the association between flavonoid intake and MAFLD with adjustments for confounders. A total of 4,431 participants were included in this cross-sectional analysis. MAFLD had a weighted prevalence of 41.93% and was not associated with total flavonoid intake. A higher anthocyanin and isoflavone intake, on the other hand, was associated with a lower prevalence of MAFLD. The protective effect of higher anthocyanin intake was significant among male, Non-Hispanic White, and Non-Hispanic Asia participants. Higher isoflavone intake was associated with a lower risk of MAFLD in participants of younger (age < 50), Non-Hispanic Black, Non-Hispanic Asia, and higher HEI-2015 scores compared with the lowest quartile of isoflavone intake. Stratified analysis showed that compared with the lowest quartile of anthocyanin intake, the effect of anthocyanin intake on MAFLD varied by racial groups (P interaction = 0.02). A positive correlation existed between HDL and anthocyanidin intake (P = 0.03), whereas a negative correlation existed between FPG and isoflavone intake (P = 0.02). MAFLD was adversely linked with flavonoid subclasses, anthocyanin and isoflavone. This modifiable lifestyle provides a potential opportunity to prevent MAFLD. These findings promote future research into the links and mechanisms between anthocyanin and isoflavone intake and MAFLD.

Potential Protective Mechanisms of S-equol, a Metabolite of Soy Isoflavone by the Gut Microbiome, on Cognitive Decline and Dementia.

S-equol, a metabolite of soy isoflavone daidzein transformed by the gut microbiome, is the most biologically potent among all soy isoflavones and their metabolites. Soy isoflavones are phytoestrogens and exert their actions through estrogen receptor-β. Epidemiological studies in East Asia, where soy isoflavones are regularly consumed, show that dietary isoflavone intake is inversely associated with cognitive decline and dementia; however, randomized controlled trials of soy isoflavones in Western countries did not generally show their cognitive benefit. The discrepant results may be attributed to S-equol production capability; after consuming soy isoflavones, 40–70% of East Asians produce S-equol, whereas 20–30% of Westerners do. Recent observational and clinical studies in Japan show that S-equol but not soy isoflavones is inversely associated with multiple vascular pathologies, contributing to cognitive impairment and dementia, including arterial stiffness and white matter lesion volume. S-equol has better permeability to the blood–brain barrier than soy isoflavones, although their affinity to estrogen receptor-β is similar. S-equol is also the most potent antioxidant among all known soy isoflavones. Although S-equol is available as a dietary supplement, no long-term trials in humans have examined the effect of S-equol supplementation on arterial stiffness, cerebrovascular disease, cognitive decline, or dementia.

Development of an Assay for Soy Isoflavones in Women's Hair.

Soy isoflavones, at adequate dosages, have estrogenic and anti-thyroidal effects in animals and humans, which can either be beneficial or adverse, depending on the consumer’s physiological status. Hence, this study presents an assay of soy isoflavones in hair, aiming to give new information about a person’s exposure to isoflavones, when health issues related to estrogenic or thyroidal effects are observed. Aqueous or organic extraction procedures following acidic, basic, or enzymatic digestions were tested on 60 hair samples (from volunteers) from a hairdresser, and a clinical trial 2017T2-29. The acidic digestion method was the most efficient regarding isoflavones. A specific inquiry was developed to assess the dietary habits of French consumers based on the analysis of 12,707 food labels from France. It was used to check for the reliability of the new assay method. A score for the consumer exposures to isoflavones was built considering, among other parameters, soy-based diets and foodstuff containing soy as an ingredient, i.e., “hidden-soy”. The correlation between this score and isoflavone measurements in hair reached 0.947; p < 0.001. Therefore, providing that relevant data are considered to assess isoflavone exposure, hair that smoothens daily isoflavone intake variations, is a relevant tissue to assess human isoflavone exposure for subsequent health analyses.

Isoflavone and soy food intake and risk of lung cancer in never smokers: report from prospective studies in Japan and China.

Evidence from several cohorts has suggested that a higher intake of isoflavone is associated with lower risk of lung cancer in never smokers, but the association has not been investigated by histologic type of lung cancer. Adenocarcinoma is a common histologic type found in never smokers. We hypothesized that a higher intake of isoflavone is associated with a lower risk of lung adenocarcinoma among never smokers. Here, we examined the associations of isoflavone and soy food intake with lung cancer and its histologic types in never smokers. We performed a pooled analysis using data from the Japan Public Health Center-based Prospective Study, Shanghai Women's Health Study and Shanghai Men's Study with 147,296 never smokers aged 40-74years with no history of cancer. During 1,990,040 person-years of follow-up, 1247 lung cancer cases were documented. Dietary isoflavone and soy food intake were assessed using a food-frequency questionnaire. Multivariable Cox proportional hazards models assessed the associations between isoflavone and soy intake with incidence of lung cancer by histologic type. A higher intake of dietary isoflavone and soy food were associated with reduced risk of lung adenocarcinoma. The multivariable hazard ratios (HRs) (95% CI) of risk of lung adenocarcinoma for the highest versus lowest intakes of isoflavone and soy food were 0.74 (0.60-0.92) and 0.78 (0.63-0.96), respectively. The multivariable HRs of risk of lung adenocarcinoma associated with each 10mg/day increase in isoflavone and each 50g/day increase in soy food intake were 0.81 (0.70-0.94) and 0.84 (0.73-0.96), respectively. Higher intake of isoflavone and soy food was associated with lower risk of lung adenocarcinoma in never smokers.