Phytoestrogen content of beverages, nuts, seeds, and oils

Enterolignans: from natural origins to cardiometabolic significance, including chemistry, dietary sources, bioavailability, and activity

The enterolignans, enterolactone and enterodiol, the main metabolites produced from plant lignans by the gut microbiota, have enhanced bioavailability and activity compared to their precursors, with beneficial effects on metabolic and cardiovascular health. Although extensively studied, the biosynthesis, cardiometabolic effects, and other therapeutic implications of mammalian lignans are still incompletely understood. The aim of this review is to provide a comprehensive overview of these phytoestrogen metabolites based on up-to-date information reported in studies from a wide range of disciplines. Established and novel synthetic strategies are described, as are the various lignan precursors, their dietary sources, and a proposed metabolic pathway for their conversion to enterolignans. The methodologies used for enterolignan analysis and the available data on pharmacokinetics and bioavailability are summarized and their cardiometabolic bioactivity is explored in detail. The special focus given to research on the health benefits of microbial-derived lignan metabolites underscores the critical role of lignan-rich diets in promoting cardiovascular health.

Validation of ELISAs for Isoflavones and Enterolactone for Phytoestrogen Intake Assessment in the French Population

Phytoestrogens are dietary compounds with low estrogenic activity. The two main categories in the French diet are isoflavones from pulses and enterolignans metabolized by the gut flora from various lignans found in fruits, vegetables, grains, and beverages. Isoflavones and lignans have different effects on human physiology and can antagonize each other. Comprehensive lists of phytoestrogen sources were constructed based on measurements and literature data. The 24 h and 48 h dietary recalls were proposed to the volunteers of the ISOLED cohort (NCT03421184). Urine and plasma samples from these volunteers were assayed for genistein, daidzein, equol, and enterolactone. A dietary score was constructed considering the pharmacokinetic characteristics of these compounds. Correlation analyses were applied to fluid concentrations associated with dietary scores. Pearson correlations reached 0.921 (p < 0.001) for urine_IF, 0.900 (p < 0.001) for plasma_IF, 0.764 (p < 0.001) for urine_ENL, and 0.723 (p < 0.001) for plasma_ENL. ELISAs associated with careful intake assessments proved to be good tools for phytoestrogens' exposure estimation.

Dietary Freeze-Dried Flaxseed and Alfalfa Sprouts as Additional Ingredients to Improve the Bioactive Compounds and Reduce the Cholesterol Content of Hen Eggs

Eggs are a complete food with high-quality proteins; a 2:1 ratio of unsaturated to saturated fatty acid (SFA); and a good amount of minerals, as well as vitamins or antioxidant compounds. Seeds or mature plants were usually added to the feed to improve egg quality. This study aimed to evaluate the effect of alfalfa and flax freeze-dried sprouts supplementation in diets of laying hens on egg oxidative status and key bioactive compounds. Thirty Sassò hens were fed with three different diets: standard, standard + 3% freeze-dried alfalfa sprouts, or flaxseed sprouts. Ten pools of 10 egg yolks per group were collected at 0, 4, and 8 weeks and analyzed. Supplementation with sprouts enriched the phytosterols, phytoestrogens, tocols, carotenes, vitamin D, and n-3 fatty acid contents in the eggs. Cholesterol content was lower in both sprout-supplemented groups, and a decrease in its oxidative products was also observed. It was found that a 3% freeze-dried sprouts supplementation of approximately 56 days improves the egg quality. Further studies are necessary to verify higher supplementing doses and the applicability of this strategy in the commercial egg production chain.

Optimizing pre-treatment of alkaline hydrolysis RP-HPLC for enhancing accuracy of soy isoflavone determination

Isoflavones (IFs) are important bioactive compounds which offers several benefits to human health. Despite the importance of IFs content, there are still some deficiencies in the existing methods. The objective of this study is to optimize key parameters of alkaline hydrolysis method for enhancing both reliability and accuracy of quantitative analysis of IFs contents in soybeans and soy protein products. Solvent type, extraction temperature, heating mode, alkaline concentration, hydrolysis temperature, hydrolysis time and some details are key points to target analytes which yield determining parameters. The biggest IFs content was obtained by extraction using methanol (MeOH)/water (80:20, v/v) in a 75 ℃ oven for 2 h, and hydrolyzation with 3 M NaOH solution at a room temperature for 10 mins. The total IFs content obtained by the improved method has increased by 16.4% compared with AOAC Official Method 2001.10. The accuracy of the method was evaluated using the relative standard deviation (RSD). Intraday accuracies in the total amount of isoflavones of four samples were 0.03%-0.63% (n = 3). Interday accuracy in the total amount of isoflavones was 2.71% (n = 6). LOD of IFs ranged from 0.1μg/mL for aglycones to 0.2μg/mL for glucosides. LOQ of IFs ranged from 0.3μg/mL for aglycones to 0.5μg/mL for glucosides. The improved method was proven to be a more accurate way to determine IFs contents in soybeans and soy protein products and thus making it useful for quality control and systematic in-depth study of soybeans and soy products; even to further assess the dietary soy exposure and the soy-health association.

Dietary Phytoestrogens and Their Metabolites as Epigenetic Modulators with Impact on Human Health

The impact of dietary phytoestrogens on human health has been a topic of continuous debate since their discovery. Nowadays, based on their presumptive beneficial effects, the amount of phytoestrogens consumed in the daily diet has increased considerably worldwide. Thus, there is a growing need for scientific data regarding their mode of action in the human body. Recently, new insights of phytoestrogens’ bioavailability and metabolism have demonstrated an inter-and intra-population heterogeneity of final metabolites’ production. In addition, the phytoestrogens may have the ability to modulate epigenetic mechanisms that control gene expression. This review highlights the complexity and particularity of the metabolism of each class of phytoestrogens, pointing out the diversity of their bioactive gut metabolites. Futhermore, it presents emerging scientific data which suggest that, among well-known genistein and resveratrol, other phytoestrogens and their gut metabolites can act as epigenetic modulators with a possible impact on human health. The interconnection of dietary phytoestrogens’ consumption with gut microbiota composition, epigenome and related preventive mechanisms is discussed. The current challenges and future perspectives in designing relevant research directions to explore the potential health benefits of dietary phytoestrogens are also explored.

Lignan exposure: a worldwide perspective

Dietary lignans are phytoestrogens that are mostly found in plant-based foods, especially whole grains, seeds, nuts, legumes and vegetables. An accurate assessment of lignan exposure is crucial to evaluate their potential health benefits and to establish future recommendations and dietary guidelines. This narrative review aimed to (i) summarize the pros and the cons of the current main assessment methods for lignan exposure─i.e., dietary questionnaires, food composition tables and biomarkers, (ii) describe the individual lignans more consumed from a worldwide perspective, as well as their main food sources, (iii) determine the lignans concentrations in both urine and blood, and explore their heterogeneity among countries, and finally (iv) discuss the main determinants of lignan exposure.

Regular consumption of "Nkui", a Cameroonian traditional dish, may protect against cardiovascular and bone disorders in an estrogen deficiency condition

OBJECTIVES

There is a growing body of evidence indicating the potential of culinary herbs and spices to decrease the incidence of several chronic diseases or conditions. Because of this, the WHO recommends their regular consumption. In the Cameroonian culinary practices, "Nkui" is a famous dish made from a mixture of 10 spices. In our previous study, the ethanolic extract of this mixture exhibited promising estrogenic properties. Thus, this study aimed to evaluate its protective effects on some menopause-related cardiovascular and bone disorders.

METHODS

For this purpose, a post-menopause-like model (ovariectomized rats) has been used. Animals were orally treated with the "Nkui" extract for 60 days. The investigation focused on the oxidative stress status, endothelial function (NO bioavailability), lipid profile, and bone mass, biochemical (calcium and inorganic phosphorus contents, serum alkaline phosphatase activity) and histomorphological features.

RESULTS

The extract regulated lipid metabolism in a way to prevent accumulation of abdominal fat, gain in body weight and increased atherogenic indexes induced by ovariectomy. It prevented menopause-related low levels of nitric oxide and oxidative stress damage by increasing superoxide dismutase and catalase activities, while reducing glutathione and malondialdehyde levels in the heart and aorta. Moreover, it prevented ovariectomy-induced bone mass loss, bone marrow disparities and the disorganization of the trabecular network. It also increased femur calcium and inorganic phosphorus contents.

CONCLUSIONS

These results suggest that a regular consumption of "Nkui" may have health benefits on cardiovascular system and osteoporosis, major health issues associated with menopause.

Diet: A Source of Endocrine Disruptors

BACKGROUND

Food is indispensable for human life and determines the health and wellbeing of the consumer. As food is the source of energy for humans, it also emerges as one of the most important sources of exposure to deleterious chemicals both natural and synthetic. The food exposed chemicals cause a number of detrimental health effects in humans, with endocrine disruption being of serious concern amongst these effects. Such chemicals disrupting the health of endocrine system are known as endocrine-disrupting chemicals (EDCs). The food exposed EDCs need to be identified and classified to effectuate a cautious consumption of food by all and especially by vulnerable groups.

AIM

The aim of the present review was to discuss food as a source of exposure to common endocrine disruptors in humans. This review presents the occurrence and levels of some of the critical endocrine disruptors exposed through frequently consumed diets.

METHODS

The major source of data was PubMed, besides other relevant publications. The focus was laid on data from the last five years, however significant earlier data was also considered.

CONCLUSION

The food as a source of endocrine disruptors to humans cannot be neglected. It is highly imperative for the consumer to recognize food as a source of EDCs and make informed choices in the consumption of food items.

Tree Nuts and Peanuts as a Source of Natural Antioxidants in our Daily Diet

Tree nuts and peanuts are healthy foods with a proven track record of helping to reduce the incidence of chronic diseases, most notably cardiovascular disease. At the point of consumption, all nuts contain low moisture and ≥ 50% lipid contents, but this is where similarities end. The levels of key nutrients and bioactives including vitamin C, vitamin E, L-arginine, minerals (such as selenium and zinc), and phenolics can differ markedly. Distinctions in the types and quantities of phenolic constituents for tree nut species, as well as the impact of digestion, will affect the nuts' antioxidant potential in vivo. This work provides some insight into the different types of phenolics found in tree nuts and peanuts, the antioxidant potential of their phenolic extracts using in vitro chemical assays, the effect of thermal processing on the stability of the nuts' endogenous phenolics, and the impact on biomarkers of human health arising from randomized clinical trials. Key biomarkers include measures in the reduction of LDL oxidation as well as increases in the levels of vitamin E and selected phenolic compounds in blood plasma postprandially from those of baseline.

A new analytical method for the simultaneous quantification of isoflavones and lignans in 25 green coffee samples by HPLC-MS/MS

Green coffee, the raw material of roasted coffee and coffee beverages, is one of the most widely traded commodities worldwide. There is a dearth of studies on its content in phytoestrogens such as isoflavones and lignans. Previously, we developed an efficient method for the simultaneous quantification of 6 isoflavones (daidzin, genistin, daidzein, genistein, formononetin and biochanin A) and 3 lignans (secoisolariciresinol, matairesinol and lariciresinol) in green coffee by using HPLC-MS/MS. Several extraction processes were evaluated and the best performing, base hydrolysis followed by enzymatic digestion, was validated and used to analyse 25 different coffee samples, 1 Coffea canephora and 24 Coffea arabica, from different countries. Lignans (total content: 286.5-8131.8 µg kg-1) were found in higher concentration than isoflavones (total content: 3.4-300.0 µg kg-1) and the most abundant were secoisolariciresinol (172.6-5714.1 µg kg-1) and lariciresinol (113.9-2417.7 µg kg-1). Notably, the Ethiopian coffee samples contained the highest levels of these compounds.

Almonds (Prunus Dulcis Mill. D. A. Webb): A Source of Nutrients and Health-Promoting Compounds

Almonds (Prunus dulcis Miller D. A. Webb (the almond or sweet almond)), from the Rosaceae family, have long been known as a source of essential nutrients; nowadays, they are in demand as a healthy food with increasing popularity for the general population and producers. Studies on the composition and characterization of almond macro- and micronutrients have shown that the nut has many nutritious ingredients such as fatty acids, lipids, amino acids, proteins, carbohydrates, vitamins and minerals, as well as secondary metabolites. However, several factors affect the nutritional quality of almonds, including genetic and environmental factors. Therefore, investigations evaluating the effects of different factors on the quality of almonds were also included. In epidemiological studies, the consumption of almonds has been associated with several therapeutically and protective health benefits. Clinical studies have verified the modulatory effects on serum glucose, lipid and uric acid levels, the regulatory role on body weight, and protective effects against diabetes, obesity, metabolic syndrome and cardiovascular diseases. Moreover, recent researchers have also confirmed the prebiotic potential of almonds. The present review was carried out to emphasize the importance of almonds as a healthy food and source of beneficial constituents for human health, and to assess the factors affecting the quality of the almond kernel. Electronic databases including PubMed, Scopus, Web of Science and SciFinder were used to investigate previously published articles on almonds in terms of components and bioactivity potentials with a particular focus on clinical trials.

Oestrogenic Endocrine Disruptors in the Placenta and the Fetus

Endocrine disrupting chemicals (EDCs) are exogenous substances that interfere with the stability and regulation of the endocrine system of the body or its offspring. These substances are generally stable in chemical properties, not easy to be biodegraded, and can be enriched in organisms. In the past half century, EDCs have gradually entered the food chain, and these substances have been frequently found in maternal blood. Perinatal maternal hormone levels are unstable and vulnerable to EDCs. Some EDCs can affect embryonic development through the blood-fetal barrier and cause damage to the neuroendocrine system, liver function, and genital development. Some also effect cross-generational inheritance through epigenetic mechanisms. This article mainly elaborates the mechanism and detection methods of estrogenic endocrine disruptors, such as bisphenol A (BPA), organochlorine pesticides (OCPs), diethylstilbestrol (DES) and phthalates (PAEs), and their effects on placenta and fetal health in order to raise concerns about the proper use of products containing EDCs during pregnancy and provide a reference for human health.

Lignans: Quantitative Analysis of the Research Literature

The current study provides a comprehensive overview and analysis of the lignan literature. Data for the current study were extracted from the electronic Web of Science Core Collection database via the search string TOPIC = ("lignan*") and processed by the VOSviewer software. The search yielded 10,742 publications. The ratio of original articles to reviews was 14.6:1. Over 80% of the analyzed papers have been published since the year 2000 and nearly 50% since the year 2010. Many of the publications were focused on pharmacology, chemistry, and plant sciences. The United States and Asian countries, such as China, Japan, South Korea, and India, were the most productive producers of lignan publications. Among the 5 most productive institutions was the University of Helsinki in Finland, the country that ranked 9^th. Nineteen journals collectively published 3,607 lignan publications and were considered as core journals. Their impact factor did not correlate with the proportion of uncited papers. Highly cited publications usually mentioned phytoestrogen, isoflavone, daidzein, enterodiol, enterolactone, equol, genistein, and isoflavonoid. Cancer (e.g., breast cancer), cardiovascular disease, and antioxidation were the major themes. Clinical trials were estimated to contribute to 0.2-1.1% of the analyzed body of literature, so more of them should be conducted in the future to substantiate the beneficial effects and optimal dose of lignan intake in humans. Moreover, researchers can refer to these findings for future research directions and collaborations.

Dietary Phytoestrogen Intake and The Risk of Endometriosis in Iranian Women: A Case-Control Study

Background

Endometriosis is an important gynecologic disease affecting reproductive-age women. Based on the effect of phytoestrogens on inflammatory, immunological and hormonal factors, limited studies have suggested that phytoestrogen consumption could probably modulate endometriosis risk. The aim of this study was to evaluate the relationship between phytoestrogen intake and endometriosis risk.

Materials and Methods

In the present case-control study, 78 women with a laparoscopically confirmed endome- triosis and 78 normal pelvis women (as the control group), were recruited. Common dietary intake was recorded by a validated 147-item semi-quantitative food frequency questionnaire (FFQ). Type of phytoestrogen in each dietary item was analyzed by the database from the United States Department of Agriculture (USDA). A logistic regression model was used to determine the association between phytoestrogen intake and endometriosis risk.

Results

Higher intake of total phytoestrogen (P-trend=0.01), total isoflavones (P-trend=0.002) specially formononetin (P-trend=0.04) and glycitein (P-trend=0.04), total lignan (P-trend=0.01) specially secoisolariciresinol (P-trend=0.01) and lariciresinol (P-trend=0.02) and matairesinol (P-trend=0.003), and total coumestrol [third quartile odds ratios (OR): 0.38; 95% confidence intervals (CI): 0.15-0.96; P-trend=0.1] was related to reduced endometriosis risk. Among food groups, only isoflavin (OR: 0.48; 95% CI: 0.44-0.63), lignan (OR: 0.66; 95% CI: 0.62-0.94), coumestrol (OR: 0.64; 95% CI: 0.51-0.99), phytoestrogen (OR: 0.46; 95% CI: 0.38-0.83) in dairy products and coumestrol in fruits (OR: 0.69; 95% CI: 0.03-0.77) were negatively associated with endometriosis risk.

Conclusion

Phytoestrogens have a major impact on the level of hormones, and immune and inflammatory markers; thus, it can play an important role in the control and prevention of many diseases. Due to the inflammatory nature of endometriosis and the effect of hormones on the progression of the disease, the role of phytoestrogens consumption in the progression and regression of the disease should be assessed in future works.

Quantification of lignans in 30 ground coffee samples and evaluation of theirs extraction yield in espresso coffee by HPLC-MS/MS triple quadrupole

Lignans are a class of polyphenols considered to be phytoestrogens because of their oestrogenic/antiestrogenic activities and their plant origin. Few works have reported on the content of lignans in ground coffee, and most of them analysed a small number of samples. Hence, our aim was to quantify the content of three lignans, secoisolariciresinol, lariciresinol and matairesinol, in ground coffee by using high-performance liquid chromatography tandem mass spectrometry. Evaluation of acidic hydrolysis, methanolic extractions, and enzymatic digestions as extraction methods indicated that enzymatic digestion with Taka-diastase 2% was the best. When this method was applied to 30 different ground coffees, we found that SECO was the highest concentration lignan (84.4-257.8 μg kg^-1), followed by LARI (26.1-91.5 μg kg^-1). Moreover, comparison of lignan extraction yield in espresso coffee and ground coffee showed that these molecules seem to be completely extracted during espresso coffee percolation, since the extraction yield average was 95.2%.

Dietary Lignans: Definition, Description and Research Trends in Databases Development

The study aims to communicate the current status regarding the development and management of the databases on dietary lignans; within the phytochemicals, the class of the lignan compounds is of increasing interest because of their potential beneficial properties, i.e., anticancerogenic, antioxidant, estrogenic, and antiestrogenic activities. Furthermore, an introductory overview of the main characteristics of the lignans is described here. In addition to the importance of the general databases, the role and function of a food composition database is explained. The occurrence of lignans in food groups is described; the initial construction of the first lignan databases and their inclusion in harmonized databases at national and/or European level is presented. In this context, some examples of utilization of specific databases to evaluate the intake of lignans are reported and described.

Development of an extraction method for the quantification of lignans in espresso coffee by using HPLC-MS/MS triple quadrupole

Lignans are polyphenolic compounds that are considered phytoestrogens for their plant origins, and they possess different biological activities. Three different extraction methods, ie, "dilute and shoot", acidic hydrolysis, and enzymatic digestion, have been compared for extracting lignans (secoisolariciresinol (SECO), matairesinol (MAT), and lariciresinol (LARI)) from espresso coffee (EC) by using high-performance liquid chromatography (HPLC) tandem mass spectrometry (MS/MS). The best recovery values (SECO: 97%, LARI: 98%, and MAT: 93%) were obtained by using enzymatic hydrolysis with Clara-Diastase at 10% (w/v), keeping the sample at 37°C for 3 hours. For this reason, this method has been chosen and then applied to quantify lignans in 9 different EC samples from 5 different geographical origins (Brazil, Colombia, El Salvador, Ethiopia, and India). Secoisolariciresinol and LARI were found in all EC samples from 27.9 to 52.0 μg L^-1 and from 5.3 to 27.8 μg L^-1 respectively, contrary to MAT that it was not possible to detect it in each type of coffee. This method confirms the high specificity and sensitivity of MS/MS system for detecting bioactives in complex matrix such as coffee.

7-Hydroxymatairesinol improves body weight, fat and sugar metabolism in C57BJ/6 mice on a high-fat diet

7-Hydroxymatairesinol (7-HMR) is a plant lignan abundant in various concentrations in plant foods. The objective of this study was to test HMRLignan™, a purified form of 7-HMR, and the correspondingPicea abiesextract (total extractP. abies; TEP) as dietary supplements on a background of a high-fat diet (HFD)-induced metabolic syndrome in mice and in the 3T3-L1 adipogenesis model. Mice, 3 weeks old, were fed a HFD for 60 d. Subgroups were treated with 3 mg/kg body weight 7-HMR (HMRLignan™) or 10 mg/kg body weight TEP by oral administration. 7-HMR and TEP limited the increase in body weight (−11 and −13 %) and fat mass (−11 and −18 %) in the HFD-fed mice. Epididymal adipocytes were 19 and −12 % smaller and the liver was less steatotic (−62 and −65 %). Serum lipids decreased in TEP-treated mice (−11 % cholesterol, −23 % LDL and −15 % TAG) and sugar metabolism was ameliorated by both lignan preparations, as shown by a more than 70 % decrease in insulin secretion and insulin resistance. The expression of several metabolic genes was modulated by the HFD with an effect that was reversed by lignan. In 3T3-L1 cells, the 7-HMR metabolites enterolactone (ENL) and enterodiol (END) showed a 40 % inhibition of cell differentiation accompanied by the inhibited expression of the adipogenic genesPPARγ,C/EBPαandaP2. Furthermore, END and ENL caused a 10 % reduction in TAG uptake in HEPA 1–6 hepatoma cells. In conclusion, 7-HMR and TEP reduce metabolic imbalances typical of the metabolic syndrome and obesity in male mice, whereas their metabolites inhibit adipogenesis and lipid uptakein vitro.

Are Total and Individual Dietary Lignans Related to Cardiovascular Disease and Its Risk Factors in Postmenopausal Women? A Nationwide Study

The study objectives were to examine total and individual lignan intakes and their dietary sources in postmenopausal Polish women and to investigate the relationship between lignan intake and the prevalence of cardiovascular disease (CVD), hypertension, hypercholesterolemia and central obesity. A total of 2599 postmenopausal women, participants of the Multi-centre National Population Health Examination Surveys (WOBASZ and WOBASZ II) were selected. Of them, 916 had a history of CVD. Nutritional data were collected using a single 24-h dietary recall. Data on lignan content in food, i.e., lariciresinol (LARI), matairesinol (MAT), pinoresinol (PINO) and secoisolariciresinol (SECO), were collected from the available lignan databases. In postmenopausal women, total and individual lignan intakes (SECO, PINO, MAT) were not associated with the prevalence of CVD and its risk factors. The intake of LARI was linked by 30% to the reduced odds for hypercholestrolemia. This study reinforces the existing concept that dietary total lignans are not associated with the prevalence of CVD, and provides further evidence that they are not linked to CVD risk factors such as hypertension, hypercholesterolemia and central obesity. However, the intake of LARI should be taken into consideration in further studies with regard to its potentially beneficial effect in hypercholesterolemia.

Phenolic Substances in Beer: Structural Diversity, Reactive Potential and Relevance for Brewing Process and Beer Quality

For the past 100 years, polyphenol research has played a central role in brewing science. The class of phenolic substances comprises simple compounds built of 1 phenolic group as well as monomeric and oligomeric flavonoid compounds. As potential anti- or prooxidants, flavor precursors, flavoring agents and as interaction partners with other beer constituents, they influence important beer quality characteristics: flavor, color, colloidal, and flavor stability. The reactive potential of polyphenols is defined by their basic chemical structure, hydroxylation and substitution patterns and degree of polymerization. The quantitative and qualitative profile of phenolic substances in beer is determined by raw material choice. During the malting and brewing process, phenolic compounds undergo changes as they are extracted or enzymatically released, are subjected to heat-induced chemical reactions or are precipitated with or adsorbed to hot and cold trub, yeast cells and stabilization agents. This review presents the current state of knowledge of the composition of phenolic compounds in beer and brewing raw materials with a special focus on their fate from raw materials throughout the malting and brewing process to the final beer. Due to high-performance analytical techniques, new insights have been gained on the structure and function of phenolic substance groups, which have hitherto received little attention. This paper presents important information and current studies on the potential of phenolics to interact with other beer constituents and thus influence quality parameters. The structural features which determine the reactive potential of phenolic substances are discussed.

Dietary Phytoestrogen Intake is Inversely Associated with Hypertension in a Cohort of Adults Living in the Mediterranean Area

Background: Dietary polyphenols, including phytoestrogens are abundantly present in a balanced diet. Evidence for their role in preventing non-communicable diseases is emerging. Methods: We examined the association between estimated habitual intakes of dietary phytoestrogens and hypertension in a cohort study. The baseline data included 1936 men and women aged 18 years and older. Intakes of total phytoestrogens, isoflavones, and lignans were calculated from validated food frequency questionnaire. Data on the polyphenols content in foods were retrieved from the Phenol-Explorer database. Results: Individuals in the highest quartile of dietary phytoestrogens intake were less likely to be hypertensive (OR: 0.66, 95% CI: 0.44–0.98); moreover, the association showed a significant decreasing trend. Isoflavones and lignans were not associated with lower odds of hypertension; however, some individual compounds, such as biochanin A and pinoresinol showed an independent inverse association with hypertension. Conclusions: Dietary phytoestrogens are associated with lower likelihood of hypertension in adults living in the Mediterranean area. Future studies are needed to confirm the present findings (i.e., prospective cohort studies) and to better understand the mechanisms underlying such associations.

Phytoestrogen Concentrations in Human Urine as Biomarkers for Dietary Phytoestrogen Intake in Mexican Women

There has been substantial interest in phytoestrogens, because of their potential effect in reducing cancer and heart disease risk. Measuring concentrations of phytoestrogens in urine is an alternative method for conducting epidemiological studies. Our objective was to evaluate the urinary excretion of phytoestrogens as biomarkers for dietary phytoestrogen intake in Mexican women. Participants were 100 healthy women from 25 to 80 years of age. A food frequency questionnaire (FFQ) and a 24 h recall were used to estimate habitual and recent intakes of isoflavones, lignans, flavonols, coumestrol, resveratrol, naringenin, and luteolin. Urinary concentrations were measured by liquid chromatography (HPLC) coupled to mass spectrometry (MS) using the electrospray ionization interface (ESI) and diode array detector (DAD) (HPLC-DAD-ESI-MS). Spearman correlation coefficients were used to evaluate associations between dietary intake and urine concentrations. The habitual consumption (FFQ) of total phytoestrogens was 37.56 mg/day. In urine, the higher compounds were naringenin (60.1 µg/L) and enterolactone (41.7 µg/L). Recent intakes (24 h recall) of isoflavones (r = 0.460, p < 0.001), lignans (r = 0.550, p < 0.0001), flavonoids (r = 0.240, p < 0.05), and total phytoestrogens (r = 0.410, p < 0.001) were correlated to their urinary levels. Total phytoestrogen intakes estimated by the FFQ showed higher correlations to urinary levels (r = 0.730, p < 0.0001). Urinary phytoestrogens may be useful as biomarkers of phytoestrogen intake, and as a tool for evaluating the relationship of intake and disease risk in Mexican women.

Plasma enterolactone and risk of prostate cancer in middle-aged Swedish men

Purpose

Enterolactone (ENL) is formed in the human gut after consumption of lignans, has estrogenic properties, and has been associated with risk of prostate cancer. We examined the association between plasma ENL levels and prostate cancer in a nested case–control study within the population-based Malmö Diet and Cancer cohort. We also examined the association between plasma ENL and dietary and lifestyle factors.

Methods

The study population consisted of 1010 cases occurring during a mean follow-up of 14.6 years, and 1817 controls matched on age and study entry date. We used national registers (95%) and hospital records (5%) to ascertain cases. Diet was estimated by a modified diet history method. Plasma ENL concentrations were determined by a time-resolved fluoroimmunoassay. Odds ratios were calculated by unconditional logistic regression.

Results

There were no significant associations between plasma ENL and incidence of all prostate cancer (odds ratio 0.99 [95% confidence interval 0.77–1.280] for the highest ENL quintile versus lowest, p for trend 0.66). However, in certain subgroups of men, including men with abdominal obesity (p for interaction = 0.012), we observed associations between high ENL levels and lower odds of high-risk prostate cancer. Plasma ENL was positively associated with consumption of high-fibre bread, fruit, tea, and coffee; with age, and with height, while it was negatively associated with smoking and waist circumference; however, although significant, all associations were rather weak (r ≤ |0.14|).

Conclusion

ENL concentration was not consistently associated with lower prostate cancer risk, although it was weakly associated with a healthy lifestyle.

Electronic supplementary material

The online version of this article (doi:10.1007/s00394-017-1530-z) contains supplementary material, which is available to authorized users.

Hemorheological effects of secoisolariciresinol in ovariectomized rats

BACKGROUND

Postmenopausal women often develop hemorheological disorders which may affect the systemic blood circulation and present a cardiovascular risk factor.

OBJECTIVE

We evaluated effects of secoisolariciresinol (SECO), a phytoestrogen, on hemorheological parameters and lipid peroxidation in a model of the age-related and/or surgical menopause induced by ovariectomy in rats.

METHODS

Arterial blood was sampled from sham-operated female rats, ovariectomized rats (OVX), and OVX treated with SECO (OVXSECO) (20 mg/kg/day intragastrically for two weeks). Plasma estrogen concentration and the following hemorheological parameters were measured: RBC aggregation (half-time of aggregation, T1/2; amplitude of aggregation, AMP; aggregation index, AI), RBC deformability (elongation index, EI), whole blood viscosity at the shear rate of 3-300 s-1, plasma viscosity, hematocrit, plasma fibrinogen. Lipid peroxidation was evaluated by measuring conjugated dienes (CD) and thiobarbituric acid reactive substances (TBARS) in plasma.

RESULTS

Ovariectomy in rats caused a 60% decrease in plasma estrogen level and triggered the development of macro- and microhemorheological abnormalities. Blood viscosity increased by 12-31%, RBC elongation index reduced by 16-28%, and T1/2 and AI increased by 35% and 29% respectively. The increase in blood viscosity correlated predominantly with reduced RBC deformability. Plasma CD and TBARS were elevated by 47% and 104% respectively. SECO therapy for OVX rats reduced blood viscosity by 9-18% and T1/2 by 32%, and increased EI by 4-17%. SECO therapy disrupted the correlation between blood viscosity and RBC deformability. Lipid peroxidation was significantly inhibited, as shown by the reduction in CD and TBARS plasma concentrations by 89% and 70% respectively. SECO did not affect plasma viscosity, estrogen or fibrinogen levels.

CONCLUSIONS

SECO treatment for OVX rats improves blood macro- and microrheological parameters, possibly through antioxidant protection of RBC.

Dietary phytoestrogens, intestinal microflora and human health

With the growth of age, the amount of estrogens produced by the human body will get less and less. Studies have shown that estrogen deficiency may cause many kinds of diseases, such as cardiovascular diseases, osteoporosis, and syndrome of menopause. Estrogens are also distributed extensively in numerous types of plants. Since there is a trace amount of natural estrogen in plants, our body can achieve continuous phytoestrogen supplementation while our health will not be influenced or damaged by the absorbed phytoestrogens in diets. After being absorbed, the phytoestrogens in diets may be converted by intestinal microflora to different metabolites with higher estrogenic activity. This review summarizes the types and distributions of phytoestrogens in diets, their metabolism, metabolites and bioactivities, with an aim to provide some guidelines for further study and utilization of microbial biotransforming metabolites of phytoestrogens.

Gastroschisis and maternal intake of phytoestrogens

The prevalence of gastroschisis has increased significantly in the past few decades. The strongest risks have been observed for women <25 years old or of low body mass index, and maternal diet also been proposed to be associated with risk. The objective of this study was to evaluate whether the risk of gastroschisis is associated with maternal dietary intake of phytoestrogens. The analysis includes data on mothers of 409 gastroschisis cases and 3,007 controls who delivered their infants from 2005 to 2010 and participated in the National Birth Defects Prevention Study, a multistate, population-based, case-control study. Detailed information was obtained from maternal telephone interviews that included a validated food frequency questionnaire. We conducted logistic regression analyses that included each phytoestrogen in its continuous form (to test for linearity) and quadratic form (to test for non-linearity), adjusted for maternal energy intake, age, BMI, race-ethnicity, and smoking in 1st trimester. Logistic regression analysis indicated that biochanin A, formonoetin, and coumestrol had a significant non-linear association with gastroschisis (P-value <0.05 for quadratic term). Lower intakes were associated with increased risk, with somewhat stronger but relatively modest associations at the lower end of the distribution; for example, the ORs for the 10th versus 50th percentiles ranged from 1.1 to 1.2. Associations were not significant for the other phytoestrogens. This study provides some evidence for association with certain phytoestrogens, after adjusting for covariates. The implications of our findings for clinical practice are uncertain pending other studies examining this association. © 2016 Wiley Periodicals, Inc.

Improving the estimation of flavonoid intake for study of health outcomes

Imprecision in estimating intakes of non-nutrient bioactive compounds such as flavonoids is a challenge in epidemiologic studies of health outcomes. The sources of this imprecision, using flavonoids as an example, include the variability of bioactive compounds in foods due to differences in growing conditions and processing, the challenges in laboratory quantification of flavonoids in foods, the incompleteness of flavonoid food composition tables, and the lack of adequate dietary assessment instruments. Steps to improve databases of bioactive compounds and to increase the accuracy and precision of the estimation of bioactive compound intakes in studies of health benefits and outcomes are suggested.

Phenolic compounds in edible species of the Anacardiaceae family – a review

Members of the Anacardiaceae (cashew family) are of economic importance and contain a diverse range of phenolic compounds.

Lupinalbin A as the most potent estrogen receptor α- and aryl hydrocarbon receptor agonist in Eriosema laurentii de Wild. (Leguminosae)

Background

Eriosema laurentii De Wild. (Leguminosae) is a plant used in Cameroon against infertility and gynecological or menopausal complaints. In our previous report, a methanol extract of its aerial parts was shown to exhibit estrogenic and aryl hydrocarbon receptor agonistic activities in vitro and to prevent menopausal symptoms in ovariectomized Wistar rats.

Methods

In order to determine the major estrogen receptor α (ERα) agonists in the extract, an activity-guided fractionation was performed using the ERα yeast screen. To check whether the ERα active fractions/compounds also accounted for the aryl hydrocarbon receptor (AhR) agonistic activity of the crude methanol extract, they were further tested on the AhR yeast screen.

Results

This study led to the identification of 2′-hydroxygenistein, lupinalbin A and genistein as major estrogenic principles of the extract. 2′-hydroxygenistein and lupinalbin A were, for the first time, also shown to possess an AhR agonistic activity, whereas genistein was not active in this assay. In addition, it was possible to deduce structure-activity relationships.

Conclusions

These results suggest that the identified compounds are the major active principles responsible for the estrogenic and AhR agonistic activities of the crude methanol extract of the aerial parts of Eriosema laurentii.

Assessment of dietary phytoestrogen intake via plant-derived foods in China

The potential influence of dietary phytoestrogen exposure on human health during different life phases including early childhood is a matter of scientific debate. In order to improve the risk-benefit assessment of exposure to dietary phytoestrogen, reliable and age-stratified exposure data are desirable. For contributing to the database on phytoestrogen exposure, in the present study plant-derived foods from the Chinese market were analysed by LC-MS/MS for their contents of phytoestrogens, including daidzein, genistein, secoisolariciresinol, glycitein and coumestrol. The analytical data showed the presence of phytoestrogens in a concentration range of less than 0.1 to about 50 μg g(-1). Dietary intake was assessed on the basis of average food intake data obtained from interviewing 1000 randomly selected people with the help of food frequency questionnaires. Based on the overall population sampled, the average total phytoestrogen intake was estimated at 232 μg kg(-1) day(-1). Genistein contributed to about 66%, secoisolariciresinol and glycitein to about 10% each, and daidzein to about 7% of the overall intake. Coumestrol was present only in trace amounts. Age-related exposure assessment indicated that pre-pubertal children (aged 0-14 years) were exposed at the highest level with an average total phytoestrogen intake of 621 μg kg(-1) day(-1). The substantially higher average exposure of children as compared with adults should trigger further research into the potential health effects of early life exposure to phytoestrogen.

Coffee intake and gastric cancer risk: the Singapore Chinese health study

BACKGROUND

Despite experimental evidence showing chemopreventive effects of coffee-related compounds on gastric carcinogenesis, epidemiologic studies generally do not support coffee-gastric cancer associations. Observational data are lacking among high-risk populations with sufficient regular coffee consumption.

METHODS

We examined the association between caffeinated coffee intake and gastric cancer risk in a population-based cohort that enrolled 63,257 Chinese men and women ages 45 to 74 years between 1993 and 1998 in Singapore. Incident gastric cancer cases (n = 647) were identified after a mean follow-up of 14.7 years. Biomarkers of Helicobacter pylori (H. pylori) infection were measured in a subset of gastric cancer cases with blood collected before cancer diagnosis and their matched controls.

RESULTS

In the total cohort, daily versus nondaily coffee intake was associated with a statistically nonsignificant decrease in gastric cancer risk [HR = 0.85; 95% confidence interval (CI), 0.69-1.04]. In women, the inverse association strengthened and reached statistical significance (HR = 0.63; 95% CI, 0.46-0.87). In analyses restricted to never smokers and nondrinkers of alcohol, inverse associations strengthened in the total cohort (HR = 0.69; 95% CI, 0.52-0.91) and in women (HR = 0.52; 95% CI, 0.37-0.74). There was no coffee-gastric cancer risk association among men, regardless of smoking status or alcohol consumption. Similar results were observed in the nested case-control study after adjustment for H. pylori infection.

CONCLUSION

Daily coffee consumption may reduce the risk of gastric cancer in high-risk populations, especially among women.

IMPACT

Research aimed at identifying the compounds in coffee that may protect against gastric carcinogenesis is warranted.

Estrogenic endocrine-disrupting chemicals: molecular mechanisms of actions on putative human diseases

Endocrine-disrupting chemicals (EDC), including phthalates, bisphenol A (BPA), phytoestrogens such as genistein and daidzein, dichlorodiphenyltrichloroethane (DDT), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), are associated with a variety of adverse health effects in organisms or progeny by altering the endocrine system. Environmental estrogens, including BPA, phthalates, and phytoestrogens, are the most extensively studied and are considered to mimic the actions of endogenous estrogen, 17β-estradiol (E2). Diverse modes of action of estrogen and estrogen receptors (ERα and ERβ) have been described, but the mode of action of estrogenic EDC is postulated to be more complex and needs to be more clearly elucidated. This review examines the adverse effects of estrogenic EDC on male or female reproductive systems and molecular mechanisms underlying EDC effects that modulate ER-mediated signaling. Mechanisms of action for estrogenic EDC may involve both ER-dependent and ER-independent pathways. Recent findings from systems toxicology of examining estrogenic EDC are also discussed.

Development of liquid chromatography-tandem mass spectrometry method for analysis of polyphenolic compounds in liquid samples of grape juice, green tea and coffee

A simple and fast method for the analysis of a wide range of polyphenolic compounds in juice, tea, and coffee samples was developed using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The method was based on a simple sample preparation "dilute and shoot" approach, and LC-MS/MS quantification using genistein-d4 as an internal standard. The performance of six different syringeless filter devices was tested for sample preparation. The method was evaluated for recoveries of polyphenols at three spiking levels in juice, tea, and coffee samples. The recoveries of the majority of polyphenols were satisfactory (70-120%), but some varied significantly (20-138%) depending on the matrix. NIST Standard Reference Materials (SRM) 3257 Catechin Calibration Solutions and 3255 Camellia sinensis (Green Tea) Extract with certified concentrations of catechin and epicatechin were used for method validation. The measurement accuracy in two SRMs was 71-113%. The method was successfully applied to the analysis of liquid samples of grape juice, green tea, and coffee.