Current Perspectives on the Physiological Activities of Fermented Soybean-Derived Cheonggukjang

The Potential of Korean Bioactive Substances and Functional Foods for Immune Enhancement

In this review, we explore the immunomodulatory properties of Korean foods, focusing on ginseng and fermented foods. One notable example is Korean red ginseng, known for its immune system-regulating effects attributed to the active ingredient, ginsenoside. Ginsenoside stimulates immune cells, enhancing immune function and suppressing inflammatory responses. With a long history, Korean red ginseng has demonstrated therapeutic effects against various diseases. Additionally, Korean fermented foods like kimchi, doenjang, chongkukjang, gochujang, vinegar, and jangajji provide diverse nutrients and bioactive substances, contributing to immune system enhancement. Moreover, traditional Korean natural herbs such as Cirsium setidens Nakai, Gomchwi, Beak-Jak-Yak, etc. possess immune-boosting properties and are used in various Korean foods. By incorporating these foods into one's diet, one can strengthen their immune system, positively impacting their overall health and well-being.

Fermented soybean foods and diabetes

The number of patients with type 2 diabetes mellitus is increasing, and its prevention and management are important. One of the factors contributing to the increased incidence of type 2 diabetes mellitus is the change in dietary habits, including a Westernized diet. Fermented foods are foods that are transformed by the action of microorganisms to produce beneficial effects in humans and have been consumed for thousands of years. The production and consumption of fermented soy foods, including natto, miso, douchi, cheonggukjang, doenjang, tempeh, and fermented soy milk, are widespread in Asian countries. This review focuses on fermented soybean foods and summarizes their effects on diabetes. Fermentation increases the content of ingredients originally contained in soybeans and adds new ingredients that are not present in the original soybeans. Recent studies have revealed that fermented soybean food modifies the gut microbiota-related metabolites by modifying dysbiosis. Furthermore, it has been reported that fermented soybean foods have antioxidant, anti-inflammatory, and anti-diabetic effects. In recent years, fermented foods, including fermented soybeans, have shown various beneficial effects. Therefore, it is necessary to continue focusing on the benefits and mechanisms of action of fermented foods.

The effect of an exopolysaccharide probiotic molecule from Bacillus subtilis on breast cancer cells

Introduction

Many well-known risk factors for breast cancer are associated with dysbiosis (an aberrant microbiome). However, how bacterial products modulate cancer are poorly understood. In this study, we investigated the effect of an exopolysaccharide (EPS) produced by the commensal bacterium Bacillus subtilis on breast cancer phenotypes. Although B. subtilis is commonly included in probiotic preparations and its EPS protects against inflammatory diseases, it was virtually unknown whether B. subtilis-derived EPS affects cancer.

Methods

This work investigated effects of EPS on phenotypes of breast cancer cells as a cancer model. The phenotypes included proliferation, mammosphere formation, cell migration, and tumor growth in two immune compromised mouse models. RNA sequencing was performed on RNA from four breast cancer cells treated with PBS or EPS. IKKβ or STAT1 signaling was assessed using pharmacologic or RNAi-mediated knock down approaches.

Results

Short-term treatment with EPS inhibited proliferation of certain breast cancer cells (T47D, MDA-MB-468, HCC1428, MDA-MB-453) while having little effect on others (MCF-7, MDA-MB-231, BT549, ZR-75-30). EPS induced G1/G0 cell cycle arrest of T47D cells while increasing apoptosis of MDA-MB-468 cells. EPS also enhanced aggressive phenotypes in T47D cells including cell migration and cancer stem cell survival. Long-term treatment with EPS (months) led to resistance in vitro and promoted tumor growth in immunocompromised mice. RNA-sequence analysis showed that EPS increased expression of pro-inflammatory pathways including STAT1 and NF-κB. IKKβ and/or STAT1 signaling was necessary for EPS to modulate phenotypes of EPS sensitive breast cancer cells.

Discussion

These results demonstrate a multifaceted role for an EPS molecule secreted by the probiotic bacterium B. subtilis on breast cancer cell phenotypes. These results warrant future studies in immune competent mice and different cancer models to fully understand potential benefits and/or side effects of long-term use of probiotics.

Research progress on the fibrinolytic enzymes produced from traditional fermented foods

Cardiovascular diseases (CVDs) are a global health problem and leading cause of death worldwide. Thrombus formation, one of the CVDs, is essentially the formation of fibrin clots. The existing thrombolytic agents have the disadvantages of high price, short half-life, and high bleeding risk; hence, there is an urgent need to find the alternative thrombolytic agents. In recent years, traditional fermented foods have been widely investigated for their outstanding effects in the prevention and treatment of thrombus formation. In this review, we have focused on fibrinolytic enzymes produced by microorganisms during the fermentation of traditional fermented foods and their potential use for treating CVDs. First, we discussed about the sources of fibrinolytic enzymes and microbial strains that produce those enzymes followed by the optimization of fermentation process, purification, and physicochemical properties of fibrinolytic enzymes. Finally, we have summarized the thrombolytic effects of fibrinolytic enzymes in humans and mice. Fibrinolytic enzymes produced by microorganisms during the fermentation of traditional fermented foods not only lyse thrombi but also acts as anti-atherosclerotic, anti-hyperlipidemia, and neuroprotection agents. Therefore, fibrinolytic enzymes from traditional fermented foods have great potential for the prevention and treatment of CVDs.

The risk of osteoporotic fracture in gastric cancer survivors: total gastrectomy versus subtotal gastrectomy versus endoscopic treatment

PURPOSES

Previous studies have suggested that there is an increased risk of osteoporotic fracture in gastric cancer survivors. However, the data was not classified according to surgery type. This study investigated the cumulative incidence osteoporotic fracture (OF) in gastric cancer survivors according to treatment modality.

METHODS

A total of 85,124 gastric cancer survivors during 2008-2016 were included. The type of surgery was classified as total gastrectomy (TG, n = 14,428)/subtotal gastrectomy (SG, n = 52,572)/endoscopic mucosal dissection and endoscopic mucosal resection (ESD/EMR, n = 18,125). The site of osteoporotic fractures included the spine, hip, wrist, and humerus. We examined cumulative incidence using Kaplan-Meier survivor analysis and cox proportional hazards regression analysis to determine the risk factor of OF.

RESULTS

The incidence of OF per 100,000 patient year was 2.6, 2.1, 1.8 in TG, SG, ESD/EMR group. The cumulative incidence rate was 2.3% at 3 years, 4.0% at 5 years, and 5.8% at 7 years in gastrectomy group, and 1.8% at 3 years, 3.3% at 5 years in the SG group, and 4.9% at 7 years postoperatively in ESD/EMR group. TG increased the risk of OF compared to patients who underwent SG (HR 1.75, 95% confidence interval [CI] 1.57-1.94), and ESD/EMR (hazard ratio [HR] 2.23, 95% CI 2.14-2.32).

CONCLUSION

Gastric cancer survivors who underwent TG had an increased osteoporotic fracture risk than did SG or ESD/EMR in these patients. The amount of gastric resection and accompanying metabolic changes seemed to mediate such risk. Additional research is needed to establish an optimal strategy for each type of surgery.

Hawaijar - An ethnic vegan fermented soybean food of Manipur, India: A comprehensive review

Hawaijar, ethnic vegan fermented soybean food of Manipur, India is culturally and gastronomically important indigenously produced food. It is alkaline, sticky, mucilaginous and slightly pungent and bears similar properties with many fermented soybean foods of Southeast Asia like natto of Japan, douchi of China, thua nao of Thailand, choongkook jang of Korea. The functional microorganism is Bacillus and has numerous health benefits like fibrinolytic enzyme, antioxidant, antidiabetic, and ACE inhibitory activities. It is also very rich in nutrients but unscrupulous production method and sale lead to food safety issues. Huge potential pathogen population upto the level of 10^7-10 cfu/g Bacillus cereus and Proteus mirabilis were detected. Recent studies revealed presence of enterotoxic and urease gene in microorganisms originated from hawaijar. Improved and regulated food chain will result in hygienic and safe hawaijar. It has scope for functional food and nutraceutical global market and hold potential to provide employment to enhance the overall socioeconomic status of the region. Scientific production of fermented soybean over the traditional methods is summarized in this paper along with food safety and health benefits. Microbiological aspects on fermented soybean along with nutritive values are critically explained inside the paper.

Fermented Kamut Sprout Extract Decreases Cell Cytotoxicity and Increases the Anti-Oxidant and Anti-Inflammation Effect

Kamut sprouts (KaS) contain several biologically active compounds. In this study, solid-state fermentation using Saccharomyces cerevisiae and Latilactobacillus sakei was used to ferment KaS (fKaS-ex) for 6 days. The fKaS-ex showed a 26.3 mg/g dried weight (dw) and 46.88 mg/g dw of polyphenol and the β-glucan contents, respectively. In the Raw264.7 and HaCaT cell lines, the non-fermented KaS (nfKaS-ex) decreased cell viability from 85.3% to 62.1% at concentrations of 0.63 and 2.5 mg/mL, respectively. Similarly, the fKaS-ex decreased cell viability, but showed more than 100% even at 1.25 and 5.0 mg/mL concentrations, respectively. The anti-inflammatory effect of fKaS-ex also increased. At 600 µg/mL, the fKaS-ex exhibited a significantly higher ability to reduce cytotoxicity by suppressing COX-2 and IL-6 mRNA expressions as well as that for IL-1β mRNA. In summary, fKaS-ex exhibited significantly lower cytotoxicity and increased anti-oxidant and anti-inflammatory properties, indicating that fKaS-ex is beneficial for use in food and other industries.

Are Fermented Foods Effective against Inflammatory Diseases?

Fermented foods have been used over the centuries in various parts of the world. These foods are rich in nutrients and are produced naturally using various biological tools like bacteria and fungi. Fermentation of edible foods has been rooted in ancient cultures to keep food for preservation and storage for a long period of time with desired or enhanced nutritional values. Inflammatory diseases like rheumatoid arthritis, osteoarthritis, and chronic inflammatory pain are chronic disorders that are difficult to treat, and current treatments for these disorders fail due to various adverse effects of prescribed medications over a long period of time. Fermented foods containing probiotic bacteria and fungi can enhance the immune system, improve gastrointestinal health, and lower the risk of developing various inflammatory diseases. Foods prepared from vegetables by fermentation, like kimchi, sauerkraut, soy-based foods, or turmeric, lack proper clinical and translational experimental studies. The current review has focused on the effectiveness of various fermented foods or drinks used over centuries against inflammation, arthritis, and oxidative stress. We also described potential limitations on the efficacies or usages of these fermented products to provide an overarching picture of the research field.

Effects of Cheonggukjang (Fermented Soybean) on the Development of Colitis-Associated Colorectal Cancer in Mice

Colorectal cancer (CRC) is the third most common type of cancer and is caused by multiple factors. Chronic inflammation, known to cause inflammatory bowel disease (IBD), is closely associated with CRC. Cheonggukjang (CJ), a traditional Korean fermented soybean, is a functional food with anti-inflammatory effects in the intestines, but its anti-cancer effects have not yet been explored. In this study, we investigated the cancer-protective effects of cheonggukjang in an azoxymethane/DSS (AOM/DSS)-induced colitis-associated colorectal cancer (CAC) mouse model. The CJ alleviated AOM/DSS-induced pathological symptoms such as colonic shortening, increased spleen weight, tumor formation, and histological changes. It also modulated pro-inflammatory and anti-inflammatory cytokine levels via the suppression of NF-κB and inflammatory mediator signaling pathways. Furthermore, the CJ improved intestinal integrity by regulating mucin-associated and tight junction proteins. In addition, it suppressed tumor growth by regulating apoptosis and proliferation. These results highlight the anti-tumor effects of CJ in an AOM/DSS-induced CAC mouse model.

Evaluation of the Safety and Effectiveness of Nutritional Supplements for Treating Hair Loss: A Systematic Review

Importance

Despite the widespread use of nutritional supplements and dietary interventions for treating hair loss, the safety and effectiveness of available products remain unclear.

Objective

To evaluate and compile the findings of all dietary and nutritional interventions for treatment of hair loss among individuals without a known baseline nutritional deficiency.

Evidence Review

The MEDLINE, Embase, and CINAHL databases were searched from inception through October 20, 2021, to identify articles written in English with original findings from investigations of dietary and nutritional interventions in individuals with alopecia or hair loss without a known baseline nutritional deficiency. Quality was assessed with Oxford Centre for Evidence Based Medicine criteria. Outcomes of interest were disease course, both objectively and subjectively measured. Data were evaluated from January 3 to 11, 2022.

Findings

The database searches yielded 6347 citations to which 11 articles from reference lists were added. Of this total, 30 articles were included: 17 randomized clinical trials (RCTs), 11 clinical studies (non-RCT), and 2 case series studies. No diet-based interventional studies met inclusion criteria. Studies of nutritional interventions with the highest-quality evidence showed the potential benefit of Viviscal, Nourkrin, Nutrafol, Lamdapil, Pantogar, capsaicin and isoflavone, omegas 3 and 6 with antioxidants, apple nutraceutical, total glucosides of paeony and compound glycyrrhizin tablets, zinc, tocotrienol, and pumpkin seed oil. Kimchi and cheonggukjang, vitamin D3, and Forti5 had low-quality evidence for disease course improvement. Adverse effects were rare and mild for all the therapies evaluated.

Conclusions and Relevance

The findings of this systematic review should be interpreted in the context of each study's design; however, this work suggests a potential role for nutritional supplements in the treatment of hair loss. Physicians should engage in shared decision-making by covering the potential risks and benefits of these treatments with patients experiencing hair loss. Future research should focus on larger RCTs with active comparators.

Microbiology, flavor formation, and bioactivity of fermented soybean curd (furu): A review

Soybeans are an important plant-based food but its beany flavor and anti-nutritional factors limit its consumption. Fermentation is an effective way to improve its flavor and nutrition. Furu is a popular fermented soybean curd and mainly manufactured in Asia, which has been consumed for thousands of years as an appetizer because of its attractive flavors. This review first classifies furu products on the basis of various factors; then, the microorganisms involved in its fermentation and their various functions are discussed. The mechanisms for the formation of aroma and taste compounds during fermentation are also discussed; and the microbial metabolites and their bioactivities are analyzed. Finally, future prospects and challenges are introduced and further research is proposed. This information is needed to protect the regional characteristics of furu and to regulate its consistent quality. The current information suggests that more in vivo experiments and further clinical trials are needed to confirm its safety and the microbial community needs to be optimized and standardized for each type of furu to improve the production process.

Melanoidins present in traditional fermented foods and beverages

Traditional fermented foods and beverages (TFFB) are an important dietary component consumed in large quantities worldwide. Currently, much attention has been focused on the health benefits of TFFB. Melanoidins, a class of bioactive substance produced in the final stage of the Maillard reaction, not only have a significant impact on sensory properties of TFFB but also contribute to the health effects. Melanoidins formed in the fermentation system with a long reaction time at low temperature could be different from those obtained from high-temperature, short-duration roasted systems due to the multiple formative stages and involvement of microorganisms and enzymes. In this paper, the current state of knowledge regarding the formation, distribution, extraction and purification, physicochemical properties, structure characteristics, and biological activities of TFFB melanoidins are comprehensively reviewed, with predominant focus on TFFB that are typically brown like douchi, miso, cheonggukjang, soy sauce, huangjiu (Chinese rice wine), beer, vinegar, and sweet wine. The current challenges and prospective recommendations for the research of melanoidins in fermented systems are also presented. In future, people should pay more attention to the basic research on TFFB melanoidins, especially purification methods and formation mechanisms, further substantiation of health properties of TFFB melanoidins in vivo, and development of specific melanoidins to fulfill technological, productive, or health needs of consumers.

Fermented Soy Products and Their Potential Health Benefits: A Review

In the growing search for therapeutic strategies, there is an interest in foods containing natural antioxidants and other bioactive compounds capable of preventing or reversing pathogenic processes associated with metabolic disease. Fermentation has been used as a potent way of improving the properties of soybean and their components. Microbial metabolism is responsible for producing the β-glucosidase enzyme that converts glycosidic isoflavones into aglycones with higher biological activity in fermented soy products, in addition to several end-metabolites associated with human health development, including peptides, phenolic acids, fatty acids, vitamins, flavonoids, minerals, and organic acids. Thus, several products have emerged from soybean fermentation by fungi, bacteria, or a combination of both. This review covers the key biological characteristics of soy and fermented soy products, including natto, miso, tofu, douchi, sufu, cheonggukjang, doenjang, kanjang, meju, tempeh, thua-nao, kinema, hawaijar, and tungrymbai. The inclusion of these foods in the diet has been associated with the reduction of chronic diseases, with potential anticancer, anti-obesity, antidiabetic, anticholesterol, anti-inflammatory, and neuroprotective effects. These biological activities and the recently studied potential of fermented soybean molecules against SARS-CoV-2 are discussed. Finally, a patent landscape is presented to provide the state-of-the-art of the transfer of knowledge from the scientific sphere to the industrial application.

Fermented food: Should patients with cardiometabolic diseases go back to an early neolithic diet?

Fermentation has been used since the Early Neolithic period to preserve foods. It has inherent organoleptic and nutritive properties that bestow health benefits, including reducing inflammation and oxidative stress, supporting the growth of salutogenic microbiota, enhancing intestinal mucosal protection and promoting beneficial immunometabolic health effects. The fermentation of food with specific microbiota increases the production salutogenic bioactive compounds that can activate Nrf2 mediated cytoprotective responses and mitigate the effects of the 'diseasome of aging' and its associated inflammageing, which presents as a prominent feature of obesity, type-2 diabetes, cardiovascular and chronic kidney disease. This review discusses the importance of fermented food in improving health span, with special reference to cardiometabolic diseases.

Fermented Food in Asthma and Respiratory Allergies—Chance or Failure?

In the last few decades, a dramatic increase in the global prevalence of allergic diseases and asthma was observed. It was hypothesized that diet may be an important immunomodulatory factor influencing susceptibility to allergic diseases. Fermented food, a natural source of living microorganisms and bioactive compounds, has been demonstrated to possess health-promoting potentials and seems to be a promising strategy to reduce the risk of various immune-related diseases, such as allergic diseases and asthma. The exact mechanisms by which allergic diseases and asthma can be alleviated or prevented by fermented food are not well understood; however, its potential to exert an effect through modulating the immune response and influencing the gut microbiota has been recently studied. In this review, we provide the current knowledge on the role of diet, including fermented foods, in preventing or treating allergic diseases and asthma.

Bioactive peptides of plant origin: distribution, functionality, and evidence of benefits in food and health

The multiple functions of peptides released from proteins have immense potential in food and health. In the past few decades, research interest in bioactive peptides of plant origin has surged tremendously, and new plant-derived peptides are continually discovered with advances in extraction, purification, and characterization technology. Plant-derived peptides are mainly extracted from dicot plants possessing bioactive functions, including antioxidant, cholesterol-lowering, and antihypertensive activities. Although the distinct functions are said to depend on the composition and structure of amino acids, the practical or industrial application of plant-derived peptides with bioactive features is still a long way off. In summary, the present review mainly focuses on the state-of-the-art extraction, separation, and analytical techniques, functional properties, mechanism of action, and clinical study of plant-derived peptides. Special emphasis has been placed on the necessity of more pre-clinical and clinical trials to authenticate the health claims of plant-derived peptides.

Protective Effects of Fermented Soybeans (Cheonggukjang) on Dextran Sodium Sulfate (DSS)-Induced Colitis in a Mouse Model

Inflammatory bowel disease (IBD) is a chronic inflammatory disease, and the incidence of IBD is increasing every year owing to changes in dietary structure. Although the exact pathogenesis of IBD is still unclear, recent evidence suggests that gut dysbiosis is closely associated with IBD pathogenesis. Cheonggukjang is a traditional Korean fermented soybean paste produced using traditional and industrial methods, and contains probiotics, which affect the gut microbiota composition. However, the protective effect of Cheonggukjang against IBD is unknown. In this study, we investigated the bacterial community structure of traditional and commercial Cheonggukjang samples, as well as the protective effect of Cheonggukjang on a dextran sulfate sodium (DSS)-induced colitis mouse model. Traditional and commercial Cheonggukjang were found to contain various type of useful probiotics in their bacterial community structure. Cheonggukjang reduced the progression of DSS-induced symptoms, such as body weight loss, colonic shortening, disease activity index, and histological changes. Further, Cheonggukjang improved the intestinal epithelial barrier integrity on DSS-induced colitis mice. In addition, Cheonggukjang suppressed the expression of proinflammatory cytokines and inflammatory mediators through the inactivation of NF-κB and MAPK signaling pathways. These results indicate that Cheonggukjang exerts protective effects against DSS-induced colitis, suggesting its possible application as a functional food for improving inflammatory diseases.

Genistein-Opportunities Related to an Interesting Molecule of Natural Origin

Nowadays, increasingly more attention is being paid to a holistic approach to health, in which diet contributes to disease prevention. There is growing interest in functional food that not only provides basic nutrition but has also been demonstrated to be an opportunity for the prevention of disorders. A promising functional food is soybean, which is the richest source of the isoflavone, genistein. Genistein may be useful in the prevention and treatment of such disorders as psoriasis, cataracts, cystic fibrosis, non-alcoholic fatty liver disease and type 2 diabetes. However, achievable concentrations of genistein in humans are low, and the use of soybean as a functional food is not devoid of concerns, which are related to genistein's potential side effects resulting from its estrogenic and goitrogenic effects.

Impact of solid-state fermentation on factors and mechanisms influencing the bioactive compounds of grains and processing by-products

Cereal and legume grains and their processing by-products are rich sources of bioactives such as phenolics with considerable health potential, but these bioactives suffer from low bioaccessibility and bioavailability, resulting in limited use. Several studies have demonstrated that solid-state fermentation (SSF) with food-grade microorganisms is effective in releasing bound phenolic compounds in cereal and legume products. In this review, we discuss the effect of SSF on cereal and legume grains and their by-products by examining the role of specific microorganisms, their hydrolytic enzymes, fermentability of agri-food substrates, and the potential health benefits of SSF-enhanced bioactive compounds. SSF with fungi (Aspergillus spp. and Rhizopus spp.), bacteria (Bacillus subtilis and lactic acid bacteria (LAB) spp.) and yeast (Saccharomyces cerevisiae) significantly increased the bioactive phenolics and antioxidant capacities in cereal and legume grains and by-products, mainly through carbohydrate-cleaving enzymes. Increased bioactive phenolic and peptide contents of SSF-bioprocessed cereal and legume grains have been implicated for improved antioxidant, anti-inflammatory, anti-carcinogenic, anti-diabetic, and angiotensin-converting-enzyme (ACE) inhibitory effects in fermented agri-food products, but these remain as preliminary results. Future research should focus on the microbial mechanisms, suitability of substrates, and the physiological health benefits of SSF-treated grains and by-products.

Beneficial Effects of Soybean-Derived Bioactive Peptides

Peptides present in foods are involved in nutritional functions by supplying amino acids; sensory functions related to taste or solubility, emulsification, etc.; and bioregulatory functions in various physiological activities. In particular, peptides have a wide range of physiological functions, including as anticancer agents and in lowering blood pressure and serum cholesterol levels, enhancing immunity, and promoting calcium absorption. Soy protein can be partially hydrolyzed enzymatically to physiologically active soy (or soybean) peptides (SPs), which not only exert physiological functions but also help amino acid absorption in the body and reduce bitterness by hydrolyzing hydrophobic amino acids from the C- or N-terminus of soy proteins. They also possess significant gel-forming, emulsifying, and foaming abilities. SPs are expected to be able to prevent and treat atherosclerosis by inhibiting the reabsorption of bile acids in the digestive system, thereby reducing blood cholesterol, low-density lipoprotein, and fat levels. In addition, soy contains blood pressure-lowering peptides that inhibit angiotensin-I converting enzyme activity and antithrombotic peptides that inhibit platelet aggregation, as well as anticancer, antioxidative, antimicrobial, immunoregulatory, opiate-like, hypocholesterolemic, and antihypertensive activities. In animal models, neuroprotective and cognitive capacity as well as cardiovascular activity have been reported. SPs also inhibit chronic kidney disease and tumor cell growth by regulating the expression of genes associated with apoptosis, inflammation, cell cycle arrest, invasion, and metastasis. Recently, various functions of soybeans, including their physiologically active functions, have been applied to health-oriented foods, functional foods, pharmaceuticals, and cosmetics. This review introduces some current results on the role of bioactive peptides found in soybeans related to health functions.

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.