Neither soyfoods nor isoflavones warrant classification as endocrine disruptors: a technical review of the observational and clinical data

The association between soyfoods or soybean products consumption and executive functioning among Chinese adolescents: A cross-sectional multicenter study

BACKGROUND

The association of soyfoods or soybean products with executive functions in the brain has been less well studied. In this study, we investigated the consumption of soyfoods or soybean products and its association with executive functions in Chinese adolescents.

METHODS

A three-stage stratified whole group sampling method was used to investigate the consumption of soyfoods or soybean products and executive functions among 1643 Chinese adolescents aged 13-15 years. One-way ANOVA and chi-square test were used to compare the basic conditions and executive functions of adolescents with different soyfoods or soybean products consumption. Linear regression analysis and logistic regression analysis were used to analyze the association between soyfoods or soybean products and executive functions.

RESULTS

The proportions of Chinese adolescents with soyfoods or soybean products consumption ≤0 time/week, 1-3 time/week, and ≥4 time/week were 41.14 %, 46.80 %, and 12.05 %, respectively. Logistic regression analysis showed that with adolescents with soyfoods or soybean products consumption ≥4 time/week as a reference, adolescents with ≤0 time/week were less likely to have executive dysfunction in inhibiting functional (OR = 17.523, 95 % CI: 7.501, 40.938), 2back (OR = 3.384, 95 % CI: 1.729, 6.623), and switching functional (OR = 7.846, 95 % CI: 3.300, 18.657), were at higher risk of executive dysfunction (P < 0.001).

CONCLUSION

Chinese adolescents' consumption of soyfoods or soybean products is inadequate and has a positive association with executive functions. The consumption of soyfoods or soybean products among Chinese adolescents should be increased in the future.

Toxicological Effects of Naturally Occurring Endocrine Disruptors on Various Human Health Targets: A Rapid Review

Endocrine-disrupting compounds are chemicals that alter the normal functioning of the endocrine system of living organisms. They can be natural (N-EDCs) or synthetic compounds (S-EDCs). N-EDCs can belong to different groups, such as phytoestrogens (PEs), including flavonoids, or mycotoxins originating from plants or fungi, and cyanotoxins, derived from bacteria. Humans encounter these substances in their daily lives. The aim of this rapid review (RR) is to provide a fine mapping of N-EDCs and their toxicological effects on human health in terms of various medical conditions or adverse consequences. This work is based on an extensive literature search and follows a rigorous step-by-step approach (search strategy, analysis strategy and data extraction), to select eligible papers published between 2019 and 2023 in the PubMed database, and to define a set of aspects characterizing N-EDCs and the different human target systems. Of the N-EDCs identified in this RR, flavonoids are the most representative class. Male and female reproductive systems were the targets most affected by N-EDCs, followed by the endocrine, nervous, bone and cardiovascular systems. In addition, the perinatal, pubertal and pregnancy periods were found to be particularly susceptible to natural endocrine disruptors. Considering their current daily use, more toxicological research on N-EDCs is required.

Legumes and pulses - a scoping review for Nordic Nutrition Recommendations 2023

Consumption of legumes and pulses is associated with various health outcomes. Therefore, when updating the Nordic Nutrition Recommendations (NNR), summarizing the best available evidence on key health outcomes regarded as relevant for the Nordic and Baltics related to the consumption of legumes was essential. The aim of this scoping review was to evaluate the updated evidence on the effect of the consumption of legumes and pulses on various health outcomes, as well as their dose-response relationship in updated systematic reviews and meta-analyses. The scoping review is built on a de novo systematic review published in 2023 and additional searches on the consumption of legumes and pulses and its various health outcomes, including cardiovascular disease (CVD), cancer, type 2 diabetes, and obesity. Current available evidence shows that the consumption of legumes and pulses is associated with a lower risk of several cancers (evidence: low-moderate), and lower all-cause mortality (evidence: moderate). The associations with CVDs are neutral or inverse, with studies generally showing favourable changes in biomarkers for CVDs. Legume consumption is associated with a lower risk of obesity (evidence: low). For type 2 diabetes, no association was found with incidence, but trials on consumption of legumes and pulses and biomarkers generally indicated protective effects. Overall, the current evidence supports dietary recommendations to increase the consumption of legumes and pulses.

The Role of Genistein in Mammalian Reproduction

Genistein is a natural compound belonging to flavonoids, having antioxidant, anti-inflammatory, and anti-neoplastic properties. Genistein is considered a phytoestrogen. As such, genistein can bind estrogen receptors (ERα and ERβ), although with a lower affinity than that of estradiol. Despite considerable work, the effects of genistein are not well established yet. This review aims to clarify the role of genistein on female and male reproductive functions in mammals. In females, at a high dose, genistein diminishes the ovarian activity regulating several pathway molecules, such as topoisomerase isoform I and II, protein tyrosine kinases (v-src, Mek-4, ABL, PKC, Syk, EGFR, FGFR), ABC, CFTR, Glut1, Glut4, 5α-reductase, PPAR-γ, mitogen-activated protein kinase A, protein histidine kinase, and recently circulating RNA-miRNA. The effect of genistein on pregnancy is still controversial. In males, genistein exerts an estrogenic effect by inducing testosterone biosynthesis. The interaction of genistein with both natural and synthetic endocrine disruptors has a negative effect on testis function. The positive effect of genistein on sperm quality is still in debate. In conclusion, genistein has a potentially beneficial effect on the mechanisms regulating the reproduction of females and males. However, this is dependent on the dose, the species, the route, and the time of administration.

Evaluation of Genistein as a Mitochondrial Modulator and Its Effects on Sperm Quality

Phytoestrogens, such as isoflavones, are bioactive compounds found in plants with defense and protection functions. In the human body, they simulate the behavior of the hormone estradiol and can modulate the function of the male hypothalamic-pituitary-gonadal axis. This study aims to describe the effects of genistein on sperm quality of Wistar rats (male/adult) after a short oral administration protocol (50 mg/day, for 5 days), focusing on mitochondrial function. No signs of toxicity were observed in the animals during the period. The testicular mass of rats from the genistein-treated group was lower than that from the control group. Isoflavone increased the number of viable Leydig and Sertoli cells, spermatogonia, and primary spermatocytes in the treated group. The rounded spermatid count was similar to the control group, and a decrease in elongated spermatids was observed in the treated group. Genistein treatment increased plasma testosterone levels in the treated group. To the best of our knowledge, this is the first report of an in vivo short protocol demonstrating that genistein administration stimulates the overall oxygen consumption in rat seminal samples. Therefore, genistein induced a pro-spermatogenesis effect, enhanced plasma testosterone levels, and increased oxygen consumption, improving sperm mitochondrial efficiency. Similar protocols can be explored in animal and human infertility issues.

Beyond Plants: The Ultra-Processing of Global Diets Is Harming the Health of People, Places, and Planet

Global food systems are a central issue for personal and planetary health in the Anthropocene. One aspect of major concern is the dramatic global spread of ultra-processed convenience foods in the last 75 years, which is linked with the rising human burden of disease and growing sustainability and environmental health challenges. However, there are also calls to radically transform global food systems, from animal to plant-derived protein sources, which may have unintended consequences. Commercial entities have moved toward this "great plant transition" with vigor. Whether motivated by profit or genuine environmental concern, this effort has facilitated the emergence of novel ultra-processed "plant-based" commercial products devoid of nutrients and fiber, and sometimes inclusive of high sugar, industrial fats, and synthetic additives. These and other ingredients combined into "plant-based" foods are often assumed to be healthy and lower in calorie content. However, the available evidence indicates that many of these products can potentially compromise health at all scales-of people, places, and planet. In this viewpoint, we summarize and reflect on the evidence and discussions presented at the Nova Network planetary health meeting on the "Future of Food", which had a particular focus on the encroachment of ultra-processed foods into the global food supply, including the plant-sourced animal protein alternatives (and the collective of ingredients therein) that are finding their way into global fast-food chains. We contend that while there has been much uncritical media attention given to the environmental impact of protein and macronutrient sources-meat vs. novel soy/pea protein burgers, etc.-the impact of the heavy industrial processing on both human and environmental health is significant but often overlooked, including effects on cognition and mental health. This calls for a more nuanced discourse that considers these complexities and refocuses priorities and value systems towards mutualistic solutions, with co-benefits for individuals, local communities, and global ecology.

Potential neuroprotective effects of fermented foods and beverages in old age: a systematic review

Purpose

Numerous articles have recently studied the involvement of the gut microbiota in neurological diseases. Aging is associated with changes in the microbiome, which implies a reduction in microbial biodiversity among other changes. Considering that the consumption of a fermented-food diet improves intestinal permeability and barrier function, it seems of interest to study its participation in the prevention of neurodegenerative diseases. This article reviews existing studies to establish whether the consumption of fermented foods and fermented beverages prevents or ameliorates neurodegenerative decline in old age.

Methods

The protocol used was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Details of the protocol for this systematic review are registered on PROSPERO (CRD42021250921).

Results

Out of 465 articles identified in the Pubmed, Scopus, and Cochrane Library databases, a total of 29 that examined the relationship of the consumption of fermented products with cognitive impairment in old people were selected (22 cohort, 4 case-control, and 3 cross-sectional studies). The results suggest that low-to-moderate alcohol consumption and daily intake of coffee, soy products, and fermented-food diets in general are associated with a lower risk of dementia and Alzheimer's disease.

Conclusion

Daily consumption of fermented foods and beverages, either alone or as part of a diet, has neuroprotective effects and slows cognitive decline in old people.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?RecordID=250921, identifier: CRD42021250921.

Soy Milk Consumption in the United States of America: An NHANES Data Report

With the increasing adoption of plant-based diets in the United States, more and more individuals replace cow milk with plant-based milk alternatives. Soy milk is a commonly used cow milk substitute, which is characterized by a higher content of polyunsaturated fatty acids and fibers. Despite these favorable characteristics, little is known about the current prevalence of soy milk consumption the United States. We used data from the National Health and Nutrition Examination Surveys (NHANES) to assess soy milk usage in the United States and identified potential predictors for its consumption in the US general population. The proportion of individuals reporting soy milk consumption in the NHANES 2015-2016 cycle was 2%, and 1.54% in the NHANES 2017-2020 cycle. Non-Hispanic Asian and Black ethnicities (as well as other Hispanic and Mexican American ethnicities in the 2017-2020 cycle) significantly increased the odds for soy milk consumption. While a college degree and weekly moderate physical activity were associated with significantly higher odds for consuming soy milk (OR: 2.21 and 2.36, respectively), sex was not an important predictor. In light of the putative health benefits of soy milk and its more favorable environmental impact as compared to cow milk, future investigations should attempt to identify strategies that may help promote its consumption in selected populations.

Parent and physician beliefs, perceptions and knowledge of plant milks for children

Background: Parent and physician perceptions of plant milk are unclear. Aim: To explore parent and physician perceptions of plant milk for children and to gain a better understanding of why parents and physicians might choose plant milk for children. Methods: A mixed methods study was conducted using a questionnaire and interviews with parents and physicians participating in the TARGet Kids! cohort study. Questionnaire data were analyzed using descriptive statistics. Interview transcripts were analyzed using thematic analysis. Results: Parents reported a variety of reasons for choosing plant milk for their children including concerns around allergies, the environment, animal welfare, plant-based diet, health benefits, taste and hormones in cow's milk. Parents gave their children various types of plant milks and physicians provided various recommendations to parents of children not consuming cow's milk. Our study identified that 79% of parents and 51% of physicians were unaware that soy milk is the recommended cow's milk substitute for children. Additionally, 26% of parents did not know some plant milks are not fortified and can contain added sugar. Three main themes were identified from interviews about why parents and physicians may choose plant milk for children: (i) healthiness of plant milk; (ii) concerns about hormones; and (iii) environmental impacts. Conclusions: Parents and physicians choose the milk that they believe is healthiest for their child or patient. However, a lack of clarity on the effects of plant milk consumption on children's health resulted in conflicting views on whether plant milk or cow's milk is healthier for children.

Soy and Gastrointestinal Health: A Review

Soybean is the most economically important legume globally, providing a major source of plant protein for millions of people; it offers a high-quality, cost-competitive and versatile base-protein ingredient for plant-based meat alternatives. The health benefits of soybean and its constituents have largely been attributed to the actions of phytoestrogens, which are present at high levels. Additionally, consumption of soy-based foods may also modulate gastrointestinal (GI) health, in particular colorectal cancer risk, via effects on the composition and metabolic activity of the GI microbiome. The aim of this narrative review was to critically evaluate the emerging evidence from clinical trials, observational studies and animal trials relating to the effects of consuming soybeans, soy-based products and the key constituents of soybeans (isoflavones, soy proteins and oligosaccharides) on measures of GI health. Our review suggests that there are consistent favourable changes in measures of GI health for some soy foods, such as fermented rather than unfermented soy milk, and for those individuals with a microbiome that can metabolise equol. However, as consumption of foods containing soy protein isolates and textured soy proteins increases, further clinical evidence is needed to understand whether these foods elicit similar or additional functional effects on GI health.

Daily Dietary Supplementation with Steamed Soybean Improves Muscle Volume and Strength in Healthy People Lacking Exercise

Various dietary protein supplements are used by the elderly and bedridden to maintain their skeletal muscle mass and functions. High-quality proteins act as an anabolic driver and help to improve muscle strength and performance. Previously, we reported that soy protein significantly attenuates denervation-induced loss of muscle mass and myofiber cross sectional area in mice with inhibition of ubiquitination and degradation of IRS-1 in tibialis anterior muscle. It also increased muscle volume and strength in bedridden patients. In the present study, we investigated the effects of dietary soybean supplementation on muscle functions in taxi drivers lacking vigorous physical exercise. We conducted a case-control study on 25 healthy, male taxi drivers between the ages of 36 and 71 y performing minimal physical exercise. They were divided into two dietary groups: the soybean diet group (n=13) who ate daily meals (dinner) supplemented with 50 g of steamed soybean for 30 d and the control diet group (n=12) who received no soybean supplement. Next, we measured the muscle cross-sectional area (CSA) and muscle strength and function in both the groups before and after 30 d of soybean intake. The body weights of both diet groups did not differ significantly over time. However, after 30 d of soybean supplementation, the soybean-fed group developed significantly higher muscle CSA and grip strength compared to the control groups. In conclusion, dietary soybean supplementation improved muscle function in taxi drivers who lacked exercise.

3-Phenyl-10-(2,3,4-trimethoxyphenyl)-9,10-dihydro-4H,8H-pyrano [2,3-f]chromene-4,8-dione

An efficient telescoped method for synthesis of 3-phenyl-10-(2,3,4-trimethoxyphenyl)-9,10-dihydro-4H,8H-pyrano[2,3-f]chromene-4,8-dione was elaborated. The presented protocol includes the one-pot multicomponent reaction of 7-hydroxy-3-phenyl-4H-chromen-4-one, 2,3,4-trimethoxybenzaldehyde and Meldrum’s acid. Advantages of this method are the application of readily available starting reagents, atom economy and easy procedure of preparation and purification of the target product. The structure of the synthesized polycyclic compound was proved by 1H, 13C-NMR, IR spectroscopy and high-resolution mass spectrometry with electrospray ionization (ESI-HRMS).

Factors Influencing Skin Aging and the Important Role of Estrogens and Selective Estrogen Receptor Modulators (SERMs)

The narrative for this overview focuses on updating the factors that influence skin aging and the important role estrogens and selective estrogen receptor modulators (SERMs) play in this process (mainly utilizing journal reports and reviews from the last four years). Estrogens have been known and studied for over a century. For many years, it has been recognized that estrogens are important in the maintenance of human skin. Women seek cosmetic and medical treatments to improve dermal health and physical characteristics to enhance their self-perception and inhibit skin aging, particularly in highly visible body areas. The goal: to retain estrogen’s positive benefits while aging and especially at/after menopause where estrogen-deficient skin contributes to the dramatic decline in skin health. In this overview, both background information and recent novel findings are included that cover aging (general mechanisms), skin aging, and factors that influence skin aging (intrinsic, extrinsic, skin microbiome and gut microbiome.) Plus, estrogen’s general role in maintaining skin health is presented through the classical estrogen receptors alpha (α) and beta (β) and non-classical (or non-genomic) estrogen receptor (G protein-coupled seven transmembrane receptor). More importantly, the various benefits of 17β-estradiol in skin health are examined (ie, skin collagen and elastin profiles that follow 17β-estradiol levels during aging and at/after menopause). Finally, a revision of information for estrogenic skin topical applications involving isoflavonoid compounds that act as SERMs, but are classified as endocrine disruptors, and a topical estrogen analog are explored to update the known and unknown characteristics of these treatments. Further study is warranted to understand the biological and molecular mechanisms by which estrogens support and enhance dermal health and wellbeing.

Consumption of soy isoflavones during the prepubertal phase delays puberty and causes hypergonadotropic hypogonadism with disruption of hypothalamic-pituitary gonadotropins regulation in male rats

Isoflavones are phytoestrogens with recognized estrogenic activity but may also affect testosterone, corticosterone and thyroid hormone levels in experimental models. However, the molecular mechanisms involved in these alterations are still unclear. Isoflavones are present in soy-based infant formula, in breast milk after the consumption of soy by the mother and are widely used for the preparation of beverages consumed by toddlers and teenagers. In this sense, we proposed to investigate the effects of soy isoflavone exposure during the prepubertal period, a recognized window of sensitivity for endocrine disruption, over the hypothalamic-pituitary-testicular (HPT) axis. For this, 42 3-week-old male Wistar rats were exposed to 0.5, 5 or 50 mg of soy isoflavones/kg from postnatal day (PND) 23 to PND60. We evaluated body growth, age at puberty, serum concentrations of LH, FSH, testosterone and estradiol, and the expression of the transcripts (mRNA) of genes encoding key genes controlling the hypothalamic-pituitary-testicular (HPT) axis. In the hypothalamus, we observed an increase in Esr1 mRNA expression (0.5 and 5 mg). In the pituitary, we observed an increase in Gnrhr mRNA expression (50 mg), a reduction in Lhb mRNA expression (0.5 mg), and a reduction in Ar mRNA expression. In the testis, we observed an increase in Lhcgr mRNA expression (50 mg) and a reduction in Star mRNA expression (0.5 and 5 mg). The serum levels of LH (5 and 50 mg) and FSH (0.5 mg) were increased, while testosterone and estradiol were reduced. Puberty was delayed in all groups. Taken together, these results suggest that prepubertal consumption of relevant levels of soy isoflavones disrupts the HPT axis, causing hypergonadotropic hypogonadism and altered expression levels of key genes regulating the axis.

The health effects of soy: A reference guide for health professionals

Soy is a hotly debated and widely discussed topic in the field of nutrition. However, health practitioners may be ill-equipped to counsel clients and patients about the use of soyfoods because of the enormous, and often contradictory, amount of research that has been published over the past 30 years. As interest in plant-based diets increases, there will be increased pressure for practitioners to gain a working knowledge of this area. The purpose of this review is to provide concise literature summaries (400-500 words) along with a short perspective on the current state of knowledge of a wide range of topics related to soy, from the cholesterol-lowering effects of soy protein to the impact of isoflavones on breast cancer risk. In addition to the literature summaries, general background information on soyfoods, soy protein, and isoflavones is provided. This analysis can serve as a tool for health professionals to be used when discussing soyfoods with their clients and patients.

The consequence and mechanism of dietary flavonoids on androgen profiles and disorders amelioration

Androgen is a kind of steroid hormone that plays a vital role in reproductive system and homeostasis of the body. Disrupted androgen balance serves as the causal contributor to a series of physiological disorders and even diseases. Flavonoids, as an extremely frequent family of natural polyphenols, exist widely in plants and foods and have received great attention when considering their inevitable consumption and estrogen-like effects. Mounting evidence illustrates that flavonoids have a propensity to interfere with androgen synthesis and metabolism, and also have a designated improvement effect on androgen disorders. Therefore, flavonoids were divided into six subclasses based on the structural feature in this paper, and the literature about their effects on androgens published in the past ten years was summarized. It could be concluded that flavonoids have the potential to regulate androgen levels and biological effects, mainly by interfering with the hypothalamic-pituitary-gonadal axis, androgen synthesis and metabolism, androgen binding with its receptors and membrane receptors, and antioxidant effects. The faced challenges about androgen regulation by flavonoids masterly include target mechanism exploration, individual heterogeneity, food matrixes interaction, and lack of clinical study. This review also provides a scientific basis for nutritional intervention using flavonoids to improve androgen disorder symptoms.

Estrogen Action and Gut Microbiome Metabolism in Dermal Health

Emerging scientific advances in microbial research linking estrogens and the gut-skin microbiome in reference to dermal health are featured in this narrative review of journal reports and reviews from January 2018 through February 2022. Background information on advances in microbial research along with defining the microbiota and microbiome is presented in brief. The development of and factors that influence the gut microbiome in health and disease as well as the intrinsic and extrinsic factors influencing the skin microbiome and skin aging are summarized. New information on the development and changes of organ microbiomes have exposed similarities between skin and gut structure/function, microbial components/diversity/taxonomy and how they impact the immune response for combating disease and enhancing wellness. Estrogens promote health and support homeostasis in general and directly impact dermal health. Moreover, the gut, based upon the level of the microbial enzyme β-glucuronidase, which regulates estrogen’s enterohepatic recirculation, constitutes a gut-skin microbial axis. This axis revolves around the systemically available estrogen to support immune function, counteract inflammation and oxidative stress, and decrease the risk of hormone-dependent skin cancers. These data support the direct effect of estrogens on skin health and the interaction of diet on dermal health via effects on the gut microflora. Finally, the potential for bioactive botanicals containing phytoestrogens or selective estrogen receptor modulators (SERMs) to evade the effects of gut β-glucuronidase expressing flora is proposed that may have a positive impact on skin.

Polyphenol and Tannin Nutraceuticals and Their Metabolites: How the Human Gut Microbiota Influences Their Properties

Nutraceuticals have been receiving increasing attention in the last few years due to their potential role as adjuvants against non-communicable chronic diseases (cardiovascular disease, diabetes, cancer, etc.). However, a limited number of studies have been performed to evaluate the bioavailability of such compounds, and it is generally reported that a substantial elevation of their plasma concentration can only be achieved when they are consumed at pharmacological levels. Even so, positive effects have been reported associated with an average dietary consumption of several nutraceutical classes, meaning that the primary compound might not be solely responsible for all the biological effects. The in vivo activities of such biomolecules might be carried out by metabolites derived from gut microbiota fermentative transformation. This review discusses the structure and properties of phenolic nutraceuticals (i.e., polyphenols and tannins) and the putative role of the human gut microbiota in influencing the beneficial effects of such compounds.

Perspective: Soybeans Can Help Address the Caloric and Protein Needs of a Growing Global Population

Feeding a growing global population with projected rising socioeconomic status will require additional sources of calories and especially protein. These sources need to align with the Sustainable Development Goals established by the Food and Agriculture Organization of the United Nations. The soybean is uniquely positioned to meet this challenge based on the following criteria: (1) Global soybean production exceeds by ~4 times the production of all pulses combined (2) Soybeans are higher in protein than other legumes and soy protein quality is similar to animal protein quality (3) Soybeans are an excellent source of healthy fat, including both essential fatty acids (4) Soybeans, like other legumes, symbiotically fix atmospheric nitrogen thereby reducing the need for fertilizer inputs (5) Greenhouse gas emissions per unit protein are lower than for nearly all other foods (6) Soybeans, like other legumes, are also recognized as an affordable food that can be incorporated into diverse diets regardless of economic standing and (7) The range of foods produced from soybeans constitutes an important position in historic and contemporary cuisines, cultures and emerging consumer trends for plant-based protein. Although most soybeans are currently used for animal feed, soybean use is dictated by consumer demand. Therefore, soybeans are well positioned to meet future global needs for energy and protein. Armed with this knowledge, health professionals can feel justified in encouraging greater consumption of soyfoods for both personal and planetary reasons.

Current perspectives on the beneficial effects of soybean isoflavones and their metabolites on plants

Soybeans have traditionally been a staple part of the human diet being highly rich in protein and lipid content. In an addition to the high nutritional components, soybeans have several functional components, like isoflavones, saponins, lecithin, and oligosaccharides. Soybeans emerge as a healthy functional food option. Isoflavones are most notable functional component of soybeans, exhibiting antioxidant activity while preventing plant-related diseases (e.g., antimicrobial and antiherbivore activities) and having positive effects on the life quality of plants. Isoflavones are thus sometimes referred to as phytochemicals. The latest research trends evince substantial interest in the biological efficacy of isoflavones in the human body as well as in plants and their related mechanisms. However, there is little information on the relationship between isoflavones and plants than beneficial human effects. This review discusses what is known about the physiological communication (transport and secretion) between isoflavones and plants, especially in soybeans.

Endocrine disruptors on and in fruits and vegetables: Estimation of the potential exposure of the French population

Fruits and vegetables are considered to be healthy compared to fats, carbohydrates, and meats. However, their production involves plant protection products (PPPs) or they can contain phytoestrogens which may exhibit endocrine effects. Thus, the exposure to the main PPPs and to phytoestrogens known as endocrine disruptors (EDs) is estimated. PPPs include fungicides, growth substances, herbicides, and insecticides authorised in France. ED-PPPs exposure is estimated from the maximum residue limits (MRLs) of 70 potential ED-PPPs used in France on 64 fruits and vegetables. The estimated exposure to potential ED-PPPs is 509 µg/d and involves agonist and antagonist substances in complex mixtures. Anti-androgens are preeminent, at 353 µg/d. Exposure to genistein and daidzein is calculated from 140 measurements in 9 categories of food-items containing soy. The global exposure to isoflavones in France is evaluated at 6700 µg/d. Phytoestrogen exposure is much higher than that of ED-PPPs. Their endocrine effects should be considered.

Soy Formula Is Not Estrogenic and Does Not Result in Reproductive Toxicity in Male Piglets: Results from a Controlled Feeding Study

Soy infant formula which is fed to over half a million infants per year contains isoflavones such as genistein, which have been shown to be estrogenic at high concentrations. The developing testis is sensitive to estrogens, raising concern that the use of soy formulas may result in male reproductive toxicity. In the current study, male White-Dutch Landrace piglets received either sow milk (Sow), or were provided milk formula (Milk), soy formula (Soy), milk formula supplemented with 17-beta-estradiol (2 mg/kg/d) (M + E2) or supplemented with genistein (84 mg/L of diet; (M + G) from postnatal day 2 until day 21. E2 treatment reduced testis weight (p < 0.05) as percentage of body weight, significantly suppressed serum androgen concentrations, increased tubule area, Germ cell and Sertoli cell numbers (p < 0.05) relative to those of Sow or Milk groups. Soy formula had no such effects relative to Sow or Milk groups. mRNAseq revealed 103 differentially expressed genes in the M + E2 group compared to the Milk group related to endocrine/metabolic disorders. However, little overlap was observed between the other treatment groups. These data suggest soy formula is not estrogenic in the male neonatal piglet and that soy formula does not significantly alter male reproductive development.

The role of soy and soy isoflavones on women's fertility and related outcomes: an update

Soy is a key food in human nutrition. It is widely used in eastern traditional cuisine and it has recently diffused among self-conscious and vegetarian diets. The success of soy mainly depends on versatility and supposed healthy properties of soy foods and soy components. Meanwhile, the possible influence on endocrine system, in particular by isoflavones, raised concerns among some researchers. The present paper aims to conduct a review of available data on the effect of soy, soy foods and soy components on women's fertility and related outcomes. Eleven interventional studies, eleven observational studies and one meta-analysis have been selected from the results of queries. A weak, not clinically relevant effect has been highlighted on cycle length and hormonal status. However, a suggestive positive influence has been shown among women with fertility issues and during assisted reproductive technologies. Overall, soy and soy components consumption do not seem to perturb healthy women's fertility and can have a favourable effect among subjects seeking pregnancy. However, because of the paucity of studies exploring the impact of soy intake on women's fertility, as well as the limited population sample size, the frequently incomplete specimens’ collection to investigate all cycle phases and the insufficient characterisation of participants, the evidence is suggestive and it needs further in-depth research taking into account all these aspects.

Soy consumption, cognitive function, and dementia

PURPOSE OF REVIEW

With the rising number of people living with dementia, the interest in modifiable risk factors including dietary intake for dementia is increasing. Although there is a growing body of evidence investigating soy's health effects, the direction and strength of the association between soy consumption and risk of dementia and cognitive decline are still uncertain. Thus, we aimed to review the evidence linking soy consumption to dementia and cognitive function.

RECENT FINDINGS

Some studies showed that higher intake of total soy products was associated with a lower risk or prevalence of cognitive impairment. Some studies pointed to an inverse association between higher tofu consumption and cognitive function, whereas a higher intake of soybean was associated with better cognitive function.

SUMMARY

Previous studies are scarce and have provided contradictory results. Soy is a high-protein alternative to red meat and processed meat. Further studies are needed to clarify the safety and potential preventive effects particularly in healthy populations before clinical disease manifestation and irreversible injury have occurred.

Case report: Goiter and overt hypothyroidism in an iodine-deficient toddler on soy milk and hypoallergenic diet

Soy-based infant formulas (SFs) are often consumed by cow's milk allergic children. However, some concerns have risen since soy intake may adversely affect thyroid function in iodine-deficient or subclinical hypothyroid individuals. We report the first Italian case of SF induced goiter and hypothyroidism registered in our country since National Iodine program has been instituted. Finally, we review cases previously reported in literature. A 22-month-old toddler with a previous diagnosis of cow's milk protein allergy came to clinical attention for important goiter and overt hypothyroidism. Detailed dietary anamnesis revealed that he was on a restrictive dietary regimen based on soymilk since 12 months of age. A temporary levothyroxine substitution was instituted to avoid hypothyroidism complications. Adequate iodine supplementation and diet diversification completely reversed SF-induced hypothyroidism and goiter, confirming the diagnostic suspicion of soymilk-induced thyroid dysfunction in a iodine-deficient toddler. This case report demonstrates the importance of careful dietary habits investigation and adequate micronutrients supplementation in children on a restrictive diet due to multiple food allergies in order to prevent nutritional deficits.

Nutritional Content and Health Profile of Single-Serve Non-Dairy Plant-Based Beverages

A growing number of people are seeking a non-dairy plant-based beverage both for their personal health, and for the health of the planet. The aim of this study was to conduct a cross-sectional survey of single-serve plant-based beverages to assess their nutritional content and health profile. A total of 51 non-dairy plant-based beverages were analyzed from the nutrition label listed on the commercial package. The various beverages contained extracts of soy (n = 14), almonds (n = 13), oats (n = 12), peas (n = 7), banana (n = 2), coconut (n = 2), and rice (n = 1). Almost one-half (45%) of the single-serve beverages had 5 g or more of protein/serving. A total of 75% and 65% of the single-serve beverages had calcium and vitamin B12 levels, respectively, fortified to at least 20% of the Daily Value (DV), while only 28% had vitamin D fortification at the 20% DV level. Two-thirds of the single-serve beverages had high sugar levels, while 39% were low in sodium, 63% were low in fat, and 96% were low in saturated fat. The single-serve plant-based beverages had more protein, calcium, vitamin B12, and sugar but less fat than the non-dairy, multi-serve plant-based beverages/ serving. A limited number of single-serve beverages met the requirements of school meal programs.

Herbal Products Used in Menopause and for Gynecological Disorders

Herbal products are often used as an alternative to pharmacological therapy. Menopausal symptoms and gynecological disorders (such as premenstrual syndrome and dysmenorrhea) are the indications where pharmacological therapy may have serious adverse events, hence many women prefer to use herbal products to help with these symptoms. Here, we reviewed plants and derived products, which are commonly used for the abovementioned indications, focusing on clinical data, safely profile and whether or not their use is justified. We noted that limited data are available on the use of some plants for alleviating the symptoms of menopause and gynecological disorders. While black cohosh (Cimicifuga racemose) and red clover (Trifolium pretense) were consistently shown to help reduce menopausal symptoms in clinical studies, currently available data do not fully support the use of fenugreek (Trigonella foenum-graecum), hops (Humulus lupulus), valerian (Valeriana officinalis), and soybean (Glycine max and Glycine soja) for this indication. For premenstrual syndrome and premenstrual dysphoric disorder, chaste tree (Vitex agnus-castus) shows effectiveness, but more clinical studies are needed to confirm such effect upon the use of evening primrose (Oenothera biennis).

Probiotics and Isoflavones as a Promising Therapeutic for Calcium Status and Bone Health: A Narrative Review

Probiotics have potential clinical effects for treating and preventing osteoporosis. Meanwhile, isoflavones have attracted much attention due to their ability to prevent postmenopausal symptoms. Research has established that probiotics and isoflavones can regulate hormones, immune cells, and the gastrointestinal system, acting as links in the gut-bone axis. However, combining the effects of probiotics and isoflavones on calcium status and bone health is a more novel and a still-evolving research area. Lactobacillus and Bifidobacterium are the foremost strains that influence bone health to a significant extent. Among the isoflavones, daidzein, genistein, and the metabolites of genistein (such as equol) stimulate bone formation. It can be concluded that probiotics and isoflavones promote bone health by regulating calcium uptake, gut microbiota, and various metabolic pathways that are associated with osteoblast activity and bone formation. Nevertheless, further experiments of probiotics and isoflavones are still necessary to confirm the association between calcium bioavailability and bone health.

Current Perspectives on the Beneficial Effects of Soybean Isoflavones and Their Metabolites for Humans

Soybeans are rich in proteins and lipids and have become a staple part of the human diet. Besides their nutritional excellence, they have also been shown to contain various functional components, including isoflavones, and have consequently received increasing attention as a functional food item. Isoflavones are structurally similar to 17-β-estradiol and bind to estrogen receptors (ERα and ERβ). The estrogenic activity of isoflavones ranges from a hundredth to a thousandth of that of estrogen itself. Isoflavones play a role in regulating the effects of estrogen in the human body, depending on the situation. Thus, when estrogen is insufficient, isoflavones perform the functions of estrogen, and when estrogen is excessive, isoflavones block the estrogen receptors to which estrogen binds, thus acting as an estrogen antagonist. In particular, estrogen antagonistic activity is important in the breast, endometrium, and prostate, and such antagonistic activity suppresses cancer occurrence. Genistein, an isoflavone, has cancer-suppressing effects on estrogen receptor-positive (ER+) cancers, including breast cancer. It suppresses the function of enzymes such as tyrosine protein kinase, mitogen-activated kinase, and DNA polymerase II, thus inhibiting cell proliferation and inducing apoptosis. Genistein is the most biologically active and potent isoflavone candidate for cancer prevention. Furthermore, among the various physiological functions of isoflavones, they are best known for their antioxidant activities. S-Equol, a metabolite of genistein and daidzein, has strong antioxidative effects; however, the ability to metabolize daidzein into S-equol varies based on racial and individual differences. The antioxidant activity of isoflavones may be effective in preventing dementia by inhibiting the phosphorylation of Alzheimer's-related tau proteins. Genistein also reduces allergic responses by limiting the expression of mast cell IgE receptors, which are involved in allergic responses. In addition, they have been known to prevent and treat various diseases, including cardiovascular diseases, metabolic syndromes, osteoporosis, diabetes, brain-related diseases, high blood pressure, hyperlipidemia, obesity, and inflammation. Further, it also has positive effects on menstrual irregularity in non-menopausal women and relieving menopausal symptoms in middle-aged women. Recently, soybean consumption has shown steep increasing trend in Western countries where the intake was previously only 1/20-1/50 of that in Asian countries. In this review, I have dealt with the latest research trends that have shown substantial interest in the biological efficacy of isoflavones in humans and plants, and their related mechanisms.