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Molecules (Basel, Switzerland) Mar 2019Phytoestrogens are naturally occurring nonsteroidal phenolic plant compounds that, due to their molecular structure and size, resemble vertebrate steroids estrogens.... (Review)
Review
Phytoestrogens are naturally occurring nonsteroidal phenolic plant compounds that, due to their molecular structure and size, resemble vertebrate steroids estrogens. This review is focused on plant flavonoids isoflavones, which are ranked among the most estrogenic compounds. The main dietary sources of isoflavones for humans are soybean and soybean products, which contain mainly daidzein and genistein. When they are consumed, they exert estrogenic and/or antiestrogenic effects. Isoflavones are considered chemoprotective and can be used as an alternative therapy for a wide range of hormonal disorders, including several cancer types, namely breast cancer and prostate cancer, cardiovascular diseases, osteoporosis, or menopausal symptoms. On the other hand, isoflavones may also be considered endocrine disruptors with possible negative influences on the state of health in a certain part of the population or on the environment. This review deals with isoflavone classification, structure, and occurrence, with their metabolism, biological, and health effects in humans and animals, and with their utilization and potential risks.
Topics: Animals; Equol; Genistein; Humans; Isoflavones; Phytoestrogens
PubMed: 30893792
DOI: 10.3390/molecules24061076 -
Journal of Nutritional Science and... 2020Soybeans contain several physiologically active ingredients, such as soy phytosterol, soyasaponin, soy protein, and lecithin, and are therefore expected to express the... (Review)
Review
Soybeans contain several physiologically active ingredients, such as soy phytosterol, soyasaponin, soy protein, and lecithin, and are therefore expected to express the functionalities of said ingredients. Among them, soy isoflavones have been studied in recent years for their various functions, including their obesity-preventing effect, blood glucose level reducing effect, osteoporosis and breast cancer risk reduction, and anti-oxidative effect, and several health promoting effects and disease preventing effects are expected. For example, it has been determined that soy isoflavones reduce body and fat weight in experiments in which mice were fed a diet containing soy isoflavones in studies on anti-obesity. Epidemiologic studies with humans have also shown that women who consume more soybeans have lower BMI than those who consume less. We previously found that soy isoflavones may have anti-obesity effects in myoblasts through the activation of transcriptional coactivator PGC-1β, which increases energy expenditure. In recent studies, a decrease in blood glucose level due to soy isoflavone was seen in an experiment in which diabetic model mice were fed a diet containing soy isoflavone. It has also been suggested that soy isoflavone intake may increase bone mineral density in postmenopausal women and reduce the risk of breast cancer. This review focuses on the actions of soy isoflavones known to date, including their anti-obesity and anti-diabetic effects, bone loss preventing effects, and cancer risk reduction effects, and introduces reports on the health promotion and disease prevention effects of soy isoflavones.
Topics: Animals; Bone Density; Health Promotion; Isoflavones; Mice; Soybean Proteins; Glycine max
PubMed: 33390391
DOI: 10.3177/jnsv.66.502 -
International Journal of Molecular... Mar 2021Based on their nutrient composition, soybeans and related foods have been considered to be nutritious and healthy for humans. Particularly, the biological activity and... (Review)
Review
Based on their nutrient composition, soybeans and related foods have been considered to be nutritious and healthy for humans. Particularly, the biological activity and subsequent benefits of soy products may be associated with the presence of isoflavone in soybeans. As an alternative treatment for menopause-related symptoms, isoflavone has gained much popularity for postmenopausal women who have concerns related to undergoing hormone replacement therapy. However, current research has still not reached a consensus on the effects of isoflavone on humans. This overview is a summary of the current literature about the processing of soybeans and isoflavone types (daidzein, genistein, and S-equol) and supplements and their extraction and analysis as well as information about the utilization of isoflavones in soybeans. The processes of preparation (cleaning, drying, crushing and dehulling) and extraction of soybeans are implemented to produce refined soy oil, soy lecithin, free fatty acids, glycerol and soybean meal. The remaining components consist of inorganic constituents (minerals) and the minor components of biologically interesting small molecules. Regarding the preventive effects on diseases or cancers, a higher intake of isoflavones is associated with a moderately lower risk of developing coronary heart disease. It may also reduce the risks of breast and colorectal cancer as well as the incidence of breast cancer recurrence. Consumption of isoflavones or soy foods is associated with reduced risks of endometrial and bladder cancer. Regarding the therapeutic effects on menopausal syndrome or other diseases, isoflavones have been found to alleviate vasomotor syndromes even after considering placebo effects, reduce bone loss in the spine and ameliorate hypertension and in vitro glycemic control. They may also alleviate depressive symptoms during pregnancy. On the other hand, isoflavones have not shown definitive effects regarding improving cognition and urogenital symptoms. Because of lacking standardization in the study designs, such as the ingredients and doses of isoflavones and the durations and outcomes of trials, it currently remains difficult to draw overall conclusions for all aspects of isoflavones. These limitations warrant further investigations of isoflavone use for women's health.
Topics: Animals; Chemical Fractionation; Dietary Supplements; Drug Evaluation, Preclinical; Hot Flashes; Humans; Isoflavones; Menopause; Metabolic Networks and Pathways; Phytoestrogens; Plant Extracts; Glycine max; Spectrum Analysis; Structure-Activity Relationship; Syndrome
PubMed: 33809928
DOI: 10.3390/ijms22063212 -
Nutrients Sep 2019Epidemiological data suggest that regular intake of isoflavones from soy reduces the incidence of estrogen-dependent and aging-associated disorders, such as menopause... (Review)
Review
Epidemiological data suggest that regular intake of isoflavones from soy reduces the incidence of estrogen-dependent and aging-associated disorders, such as menopause symptoms in women, osteoporosis, cardiovascular diseases and cancer. Equol, produced from daidzein, is the isoflavone-derived metabolite with the greatest estrogenic and antioxidant activity. Consequently, equol has been endorsed as having many beneficial effects on human health. The conversion of daidzein into equol takes place in the intestine via the action of reductase enzymes belonging to incompletely characterized members of the gut microbiota. While all animal species analyzed so far produce equol, only between one third and one half of human subjects (depending on the community) are able to do so, ostensibly those that harbor equol-producing microbes. Conceivably, these subjects might be the only ones who can fully benefit from soy or isoflavone consumption. This review summarizes current knowledge on the microorganisms involved in, the genetic background to, and the biochemical pathways of, equol biosynthesis. It also outlines the results of recent clinical trials and meta-analyses on the effects of equol on different areas of human health and discusses briefly its presumptive mode of action.
Topics: Animals; Bacteria; Diet; Equol; Gastrointestinal Microbiome; Health Status; Humans; Isoflavones
PubMed: 31527435
DOI: 10.3390/nu11092231 -
Nutrients Nov 2019Isoflavones have gained popularity as an alternative treatment for menopausal symptoms for people who cannot or are unwilling to take hormone replacement therapy....
Isoflavones have gained popularity as an alternative treatment for menopausal symptoms for people who cannot or are unwilling to take hormone replacement therapy. However, there is still no consensus on the effects of isoflavones despite over two decades of vigorous research. This systematic review aims to summarize the current literature on isoflavone supplements, focusing on the active ingredients daidzein, genistein, and S-equol, and provide a framework to guide future research. We performed a literature search in Ovid Medline using the search terms "isoflavone" and "menopause", which yielded 95 abstracts and 68 full-text articles. We found that isoflavones reduce hot flashes even accounting for placebo effect, attenuate lumbar spine bone mineral density (BMD) loss, show beneficial effects on systolic blood pressure during early menopause, and improve glycemic control in vitro. There are currently no conclusive benefits of isoflavones on urogenital symptoms and cognition. Due to the lack of standardized research protocols including isoflavone component and dosage, outcomes, and trial duration, it is difficult to reach a conclusion at this point in time. Despite these limitations, the evidence thus far favors the use of isoflavones due to their safety profile and benefit to overall health.
Topics: Dietary Supplements; Female; Humans; Isoflavones; Menopause
PubMed: 31689947
DOI: 10.3390/nu11112649 -
Impact of Soy Foods on the Development of Breast Cancer and the Prognosis of Breast Cancer Patients.Forschende Komplementarmedizin (2006) 2016The relationship between soy food intake and breast cancer has been rigorously investigated for more than 25 years. The identification of isoflavones as possible... (Review)
Review
The relationship between soy food intake and breast cancer has been rigorously investigated for more than 25 years. The identification of isoflavones as possible chemopreventive agents helped fuel this line of investigation. These diphenolic compounds, which are found in uniquely-rich amounts in soy beans, possess both estrogen-dependent and -independent properties that potentially inhibit the development of breast cancer. Observational studies show that among Asian women higher soy consumption is associated with an approximate 30% reduction in risk of developing breast cancer. However, evidence suggests that for soy to reduce breast cancer risk consumption must occur early in life, that is during childhood and/or adolescence. Despite the interest in the role of soy in reducing breast cancer risk concerns have arisen that soy foods, because they contain isoflavones, may increase the likelihood of high-risk women developing breast cancer and worsen the prognosis of breast cancer patients. However, extensive clinical and epidemiologic data show these concerns to be unfounded. Clinical trials consistently show that isoflavone intake does not adversely affect markers of breast cancer risk, including mammographic density and cell proliferation. Furthermore, prospective epidemiologic studies involving over 11,000 women from the USA and China show that postdiagnosis soy intake statistically significantly reduces recurrence and improves survival.
Topics: Adolescent; Adult; Age Factors; Breast Neoplasms; Child; Diet, Vegetarian; Female; Humans; Isoflavones; Prognosis; Risk; Soy Foods; United States
PubMed: 27161216
DOI: 10.1159/000444735 -
Antioxidants & Redox Signaling Jul 2013Oxidative stress has been mechanistically linked with aging and chronic diseases, including cancer. In fact, oxidative stress status, chronic disease-related... (Review)
Review
SIGNIFICANCE
Oxidative stress has been mechanistically linked with aging and chronic diseases, including cancer. In fact, oxidative stress status, chronic disease-related inflammation, and cancer occurred in the aging population are tightly correlated. It is well known that the activation of nuclear factor kappa B (NF-κB) plays important roles in oxidative stress, inflammation, and carcinogenesis. Therefore, targeting NF-κB is an important preventive or therapeutic strategy against oxidative stress, inflammation, and cancer.
RECENT ADVANCES
A variety of natural compounds has been found to reduce oxidative stress through their antioxidant activity. Among them, isoflavone, indole-3-carbinol (I3C), and its in vivo dimeric compound 3,3'-diindolylmethane (DIM) have shown their promising effects on the inhibition of NF-κB with corresponding reduction of oxidative stress.
CRITICAL ISSUES
It has been found that isoflavone, I3C, and DIM could inhibit cancer development and progression by regulating multiple cellular signaling pathways that are related to oxidative stress and significantly deregulated in cancer.
FUTURE DIRECTIONS
The antioxidative and anticancer effects of these natural agents make them strong candidates for chemoprevention and/or therapy against human malignancies. However, more clinical trials are needed to evaluate the effects of isoflavone and DIM for the prevention of cancer development and also for the treatment of cancer either alone or in combination with conventional cancer therapeutics.
Topics: Animals; Anticarcinogenic Agents; Antineoplastic Agents; Antioxidants; Biological Factors; Humans; Indoles; Isoflavones; Neoplasms
PubMed: 23391445
DOI: 10.1089/ars.2013.5233 -
Oxidative Medicine and Cellular... 2021Daidzein is a phytoestrogen isoflavone found in soybeans and other legumes. The chemical composition of daidzein is analogous to mammalian estrogens, and it could be... (Review)
Review
Daidzein is a phytoestrogen isoflavone found in soybeans and other legumes. The chemical composition of daidzein is analogous to mammalian estrogens, and it could be useful with a dual-directional purpose by substituting/hindering with estrogen and estrogen receptor (ER) complex. Hence, daidzein puts forth shielding effects against a great number of diseases, especially those associated with the control of estrogen, such as breast cancer, diabetes, osteoporosis, and cardiovascular disease. However, daidzein also has other ER-independent biological activities, such as oxidative damage reduction acting as an antioxidant, immune regulator as an anti-inflammatory agent, and apoptosis regulation, directly linked to its potential anticancer effects. In this sense, the present review is aimed at providing a deepen analysis of daidzein pharmacodynamics and its implications in human health, from its best-known effects alleviating postmenopausal symptoms to its potential anticancer and antiaging properties.
Topics: Animals; Cardiovascular Diseases; Humans; Isoflavones; Neoplasms; Neuroprotective Agents; Osteoporosis; Oxidative Stress; Glycine max
PubMed: 34539970
DOI: 10.1155/2021/6331630 -
Nutrition Journal Mar 2024Previous experimental studies have suggested that the consumption of soy isoflavones may have a potential impact on lowering blood pressure. Nevertheless,... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Previous experimental studies have suggested that the consumption of soy isoflavones may have a potential impact on lowering blood pressure. Nevertheless, epidemiological studies have presented conflicting outcomes concerning the correlation between soy isoflavone consumption and blood pressure levels. Consequently, a comprehensive meta-analysis of all eligible randomized controlled trials (RCTs) was conducted to explore the influence of soy isoflavones on systolic blood pressure (SBP) and diastolic blood pressure (DBP) in adults.
METHODS
A thorough search of PubMed, Embase, and the Cochrane Library for relevant literature up to April 30, 2023 was conducted. RCTs involving adults that compared soy isoflavone supplementation with a placebo (the same matrix devoid of soy isoflavone) were included. The combined effect size was presented as the weighted mean difference (WMD) along with 95% confidence interval (CI), employing a fixed-effects model.
RESULTS
Our meta-analysis included a total of 24 studies involving 1945 participants. The results revealed a significant reduction in both SBP and DBP with soy isoflavone supplementation. Subgroup analyses suggested more pronounced reductions in SBP and DBP for interventions lasting ≥6 months, in individuals receiving mixed-type soy isoflavone, and among patients with metabolic syndrome or prehypertension. However, we did not detect significant nonlinear associations between supplementation dosage and intervention duration concerning both SBP and DBP. The overall quality of evidence was deemed moderate.
CONCLUSIONS
The current meta-analysis revealed that supplementation with soy isoflavones alone effectively reduces blood pressure. Additional high-quality studies are required to investigate the efficacy of blood pressure reduction through supplementation with an optimal quantity and proportion of soy isoflavone.
Topics: Humans; Blood Pressure; Dietary Supplements; Hypertension; Isoflavones; Randomized Controlled Trials as Topic
PubMed: 38454401
DOI: 10.1186/s12937-024-00932-6 -
Oncotarget Dec 2016
Topics: Genistein; Hippocampus; Isoflavones; Neurogenesis
PubMed: 27895311
DOI: 10.18632/oncotarget.13534