Plasma isoflavone concentrations are not associated with gastric cancer risk among Japanese men and women

Circulating Proteins and Metabolite Biomarkers in Gastric Cancer: A Systematic Review and Meta-analysis

BACKGROUND

Gastric cancer (GC) is often diagnosed at an advanced stage and thus patients have a poor prognosis. This implies that early detection of this cancer will improve patient prognosis and survival. This systematic review explored the association of circulating protein and metabolite biomarkers with GC development.

METHODS

A literature search was conducted until November 2021 on Medline, Embase, Cochrane library, and Web of Science databases. Studies were included if they assessed circulating proteins and metabolites in blood, urine, or saliva and determined their association with GC risk. Quality of identified studies was determined using the Newcastle-Ottawa scale for cohort studies. Random and fixed effects meta-analyses were performed to calculate pooled odds ratio.

RESULTS

A total of 53 studies were included. High levels of anti-Helicobacter pylORi IgG levels, pepsinogen I (PGI) <30 µg/L and serum pepsinogen I/ pepsinogen II (PGI/II) ratio<3 were positively associated with risk of developing GC (pooled odds ratio (OR): 2.70; 95% CI: 1.44-5.04, 5.96, 95% CI: 2.65-13.42 and 4.43; 95% CI: 3.04-6.47). In addition, an inverse relationship was found between ferritin, iron and transferrin levels and risk of developing GC (OR: 0.62; 95% CI: 0.38-1,0.97; 95% CI: 0.94-1 and 0.85; 95% CI: 0.76-0.94). However, there was no association between levels of glucose, cholesterol, vitamin C, vitamin B12, vitamin A, α-Carotene, β-Carotene, α-Tocopherol, γ-Tocopherol, and GC risk.

CONCLUSION

The pooled analysis demonstrated that high levels of anti-Helicobacter pylORi IgG, PGI<30µg/L and serum PGI/II ratio <3 and low levels of ferritin, iron and transferrin were associated with risk of GC.

Genistein: Therapeutic and Preventive Effects, Mechanisms, and Clinical Application in Digestive Tract Tumor

Genistein is one of the numerous recognized isoflavones that may be found in a variety of soybeans and soy products, including tofu and tofu products. The chemical name for genistein is 4', 5, 7-trihydroxyisoflavone, and it is found in plants. In recent years, the scientific world has become more interested in genistein because of its possible therapeutic effects on many forms of cancer. It has been widely investigated for its anticancer properties. The discovery of genistein's mechanism of action indicates its potential for apoptosis induction and cell cycle arrest in gastrointestinal cancer, especially gastric and colorectal cancer. Genistein's pharmacological activities as determined by the experimental studies presented in this review lend support to its use in the treatment of gastrointestinal cancer; however, additional research is needed in the future to determine its efficacy, safety, and the potential for using nanotechnology to increase bioavailability and therapeutic efficacy.

Strategies to achieve significant physiological concentrations of bioactive phytoestrogens in plasma

The benefits to health attributed to the intake of phytoestrogens (PEs) have been demonstrated in previous studies with significant physiological concentrations of bioactive PEs, such as genistein, equol, enterolignans and urolithins in plasma. However, the achievement of high bioactive PE levels in plasma is restricted to a select population group, mainly due to the low intake of plant PEs and/or the absence, or inhibition, of the microbiota capable of producing these bioactive forms. In this study, the intake of plant PEs, the concentration of bioactive PEs in plasma, the ability of the intestinal microbiota to produce bioactive PEs, as well as the different mechanisms used by GRAS bacteria to increase the level of bioactive PEs were evaluated concluding that the use of GRAS bacteria bioactive PE producers and the development of fermented foods enriched in bioactive PEs in addition to a high intake of plant PEs and taking care of the intestinal microbiota, are some of the different strategies to achieve significant physiological concentrations of bioactive PEs in the intestine and, subsequently, in plasma and targets organs which are essential to improve menopausal symptoms or reduce the risk of some pathologies such as breast and colon cancer, or cardiovascular disease.

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

Soybeans are a rich source of isoflavones, which are classified as phytoestrogens. Despite numerous proposed benefits, isoflavones are often classified as endocrine disruptors, based primarily on animal studies. However, there are ample human data regarding the health effects of isoflavones. We conducted a technical review, systematically searching Medline, EMBASE, and the Cochrane Library (from inception through January 2021). We included clinical studies, observational studies, and systematic reviews and meta-analyses (SRMA) that examined the relationship between soy and/or isoflavone intake and endocrine-related endpoints. 417 reports (229 observational studies, 157 clinical studies and 32 SRMAs) met our eligibility criteria. The available evidence indicates that isoflavone intake does not adversely affect thyroid function. Adverse effects are also not seen on breast or endometrial tissue or estrogen levels in women, or testosterone or estrogen levels, or sperm or semen parameters in men. Although menstrual cycle length may be slightly increased, ovulation is not prevented. Limited insight could be gained about possible impacts of in utero isoflavone exposure, but the existing data are reassuring. Adverse effects of isoflavone intake were not identified in children, but limited research has been conducted. After extensive review, the evidence does not support classifying isoflavones as endocrine disruptors.

Effects of Isolated Isoflavones Intake on Health

BACKGROUND

Isoflavones are naturally occurring flavonoids, commonly found in the food consumed for centuries in the East-Asian population, characterized by a structure able to exert nonsteroidal estrogen-like activity on human cells. They have attracted researcher interest all around the word, following the results obtained in epidemiological and clinical studies. The involvement of isoflavones and their metabolites in various biological processes suggests that they can influence several metabolic pathways and can influence the gene expression at epigenetic level, involving effects that probably are due to early life exposure. They show positive health effects on several diseases, especially in the prevention of coronary heart and neurological diseases, hormone-related cancers, osteoporosis, and postmenopausal symptoms.

METHODS

We have performed a critical evaluation of available literature trough a structured search of bibliographic databases about isoflavones health promoting properties, risk assessment and mechanisms of action. In addition, we supplied useful information on their biochemical properties, sources and bioavailability.

RESULTS

Although these molecules have been the subjects of numerous researches, their role for the wellness of the human organism remains controversial. Moreover, there are substantial inconsistencies between the results obtained by epidemiologic studies conducted on Eastern population, which found high health promoting properties, and Western clinical trials, which found much less positive effects.

CONCLUSION

Further epidemiologic studies and well-designed prospective human studies are to determine the beneficial effects of isoflavones exposure, as well as establishing its safe therapeutic.

Bacterial metabolism as responsible of beneficial effects of phytoestrogens on human health

Phytoestrogens (PE) are compounds found in plants such as soy (isoflavones), flax seeds and cereals (lignans) and pomegranates (ellagitannins). PE have shown estrogenic/antiestrogenic, antioxidant, anti-inflammatory, antineoplastic and apoptotic activities. The human studies are showing promising although inconsistent results about the beneficial effects of PE on ameliorating the menopausal symptoms or reducing the risk of certain cancers, cardiovascular disease or diabetes. The effects of PE on the organism are mediated by the intestinal microbiota, which transforms them into bioactive PE such as genistein, equol, enterolignans and certain urolithins. In this work, we review the most recent findings about the bacteria able to metabolize PE, together with the latest studies on the effects of PE on health. In addition, we describe the possible factors hindering the demonstration of the beneficial effect of PE on health, evincing the importance of measuring the actual circulating PE in order to encompass the variability of PE metabolism due to the intestinal microbiota. With this in mind, we also explore an approach to ensure the access to bioactive PE.

Environmental contributions to gastrointestinal and liver cancer in the Asia-Pacific region

In the Asia-Pacific region, gastric, colorectal, and hepatocellular (liver) cancer show substantial regional variation in incidence consistent with the presence of important environmental factors. For gastric cancer, global incidence is concentrated in Asia with substantially higher rates in East Asia than in South-East Asia and Australia. The differences in incidence rates for gastric cancer in the Asia-Pacific region may be due, in part, to differences in the prevalence of Helicobacter pylori infection and the prevalence of H. pylori virulence factors. Smoking is also correlated with gastric cancer risk and is responsible for the highest population attributable fraction among men in East Asia. Colorectal cancer has increased rapidly in incidence to become the third most common digestive cancer in Asia. According to cohort studies in Asia, smoking, alcohol use, obesity, and physical inactivity increase the risk of colorectal cancer. Unlike West Asia, East Asia and Australia have high incidence rates for colorectal cancer that correlates to a high Human Development Index and a high prevalence of alcohol consumption and obesity. Liver cancer is the second most common digestive cancer in Asia. The high incidence of liver cancer in East Asia and South-East Asia is concordant with the high prevalence of hepatitis B virus and hepatitis C virus infection. Other important risk factors include alcohol use, smoking, and diabetes. The identification of the earlier and other environmental factors (currently under investigation) is central to the development and implementation of effective cancer control programs for the region.

Meta-analysis of Soy Consumption and Gastrointestinal Cancer Risk

Soy consumption has received considerable attention for its potential role in reducing cancer incidence and mortality. However, its effects on gastrointestinal (GI) cancer are controversial. Therefore, we performed a meta-analysis to evaluate the association between soy consumption and gastrointestinal cancer risk by searching for prospective studies in PubMed, Web of Science, EMBASE and the reference lists of the included articles. The study-specific odds ratio (OR), relative risk (RR) or hazard ratio (HR) estimates and 95% confidence intervals (CIs) were pooled using either a fixed-effect or random-effect model. Twenty-two independent prospective studies were eligible for our meta-analysis, including 21 cohort studies and one nested case-control study. Soy product consumption was inversely associated with the incidence of overall GI cancer (0.857; 95% CI: 0.766, 0.959) and the gastric cancer subgroup (0.847; 95% CI: 0.722, 0.994) but not the colorectal cancer subgroup. After stratifying the results according to gender, an inverse association was observed between soy product intake and the incidence of GI cancer for females (0.711; 95% CI: 0.506, 0.999) but not for males.

Dietary isoflavones and gastric cancer: A brief review of current studies

Background:

Although several in vitro and animal studies have suggested that isoflavones might exert inhibitory effects on gastric carcinogenesis, epidemiologic studies have reported inconclusive results in this field. The aim of this brief review was to investigate whether such an association exists among dietary isoflavones and gastric cancer incidence, prevention, and mortality in epidemiologic studies.

Materials and Methods:

We conducted a search of PubMed, Google Scholar, Cochrane, Science direct, and Iranian Scientific Databases including Scientific Information Database and IranMedex Database (up to November 2014) using common keywords for studies that focused on dietary isoflavones and gastric cancer risk.

Results:

A total of nine epidemiologic studies consisting of five case-controls, three prospective cohorts, and one ecologic study were included in this review. An inverse association between dietary isoflavones and gastric cancer was shown in only one case-control and one ecologic study.

Conclusion:

In summary, whether anticarcinogenic properties of isoflavones are established, research found no substantial correlation in this field. There are insufficient studies to draw any firm conclusions about the relationship between isoflavones intake and the risk of gastric cancer. Hence, further evidence from cohort and trial studies are needed.

Genistein and cancer: current status, challenges, and future directions

Primary prevention through lifestyle interventions is a cost-effective alternative for preventing a large burden of chronic and degenerative diseases, including cancer, which is one of the leading causes of morbidity and mortality worldwide. In the past decade, epidemiologic and preclinical evidence suggested that polyphenolic phytochemicals present in many plant foods possess chemopreventive properties against several cancer forms. Thus, there has been increasing interest in the potential cancer chemopreventive agents obtained from natural sources, such as polyphenols, that may represent a new, affordable approach to curb the increasing burden of cancer throughout the world. Several epidemiologic studies showed a relation between a soy-rich diet and cancer prevention, which was attributed to the presence of a phenolic compound, genistein, present in soy-based foods. Genistein acts as a chemotherapeutic agent against different types of cancer, mainly by altering apoptosis, the cell cycle, and angiogenesis and inhibiting metastasis. Targeting caspases, B cell lymphoma 2 (Bcl-2)-associated X protein (Bax), Bcl-2, kinesin-like protein 20A (KIF20A), extracellular signal-regulated kinase 1/2 (ERK1/2), nuclear transcription factor κB (NF-κB), mitogen-activated protein kinase (MAPK), inhibitor of NF-κB (IκB), Wingless and integration 1 β-catenin (Wnt/β-catenin), and phosphoinositide 3 kinase/Akt (PI3K/Akt) signaling pathways may act as the molecular mechanisms of the anticancer, therapeutic effects of genistein. Genistein also shows synergistic behavior with well-known anticancer drugs, such as adriamycin, docetaxel, and tamoxifen, suggesting a potential role in combination therapy. This review critically analyzes the available literature on the therapeutic role of genistein on different types of cancer, focusing on its chemical features, plant food sources, bioavailability, and safety.

Biomarkers of Dietary Polyphenols in Cancer Studies: Current Evidence and Beyond

Polyphenols, commonly contained in fruits and vegetables, have long been associated with a protective role against multiple diseases and adverse health effects. Generally, in vitro and animal experiments have provided strong positive evidence, whereas evidence from in vivo and human epidemiological studies is not strong enough. Most epidemiological studies to date use food frequency questionnaire based dietary intake estimations, which inevitably incur imprecision. Biomarkers of polyphenol have the potential to complement and enhance current studies. This review performed a literature search of all epidemiological studies or controlled clinical/intervention trials which employed biomarkers of exposure for polyphenols to help assess their anticarcinogenic role, using studies on green tea polyphenols as a study model. Currently, studies on this topic are still limited; breast cancer and prostate cancer were the only widely studied cancer types. Isoflavone is the only widely studied polyphenol. In addition to associations between polyphenols and cancer risks, factors such as host genetic susceptibility, epigenetic modification, and gut microbiome patterns may also impact on the protective roles of polyphenols. More evidence should be collected by utilizing biomarkers of exposure for polyphenols in future epidemiological studies before a clear conclusion can be made.

Plasma isoflavones and risk of primary liver cancer in Japanese women and men with hepatitis virus infection: a nested case-control study

BACKGROUND

Evidence suggests that estrogen plays a preventive role in primary liver cancer development, and it might be thought that isoflavones, which are structurally similar to estrogens and bind to estrogen receptors, are associated with the risk of liver cancer. We investigated this suspected association by measuring plasma concentrations of isoflavones in a nested case-control study of a population-based prospective cohort in Japan.

METHODS

From 18,628 target participants ages 40 to 69 years who returned the baseline questionnaire and provided blood samples, we selected those with either hepatitis B or hepatitis C virus infection at baseline (n = 1,544). Among these, 90 (28 women and 62 men) were newly diagnosed with primary liver cancer from 1993 through 2006; they were matched with 175 controls (54 women and 121 men). Plasma concentrations of isoflavones (genistein, daidzein, glycitein, and equol) were measured using triple quadrupole tandem liquid chromatography-mass spectrometry. The ORs of liver cancer development based on plasma concentrations were estimated with a conditional logistic regression model.

RESULTS

Basically, distributions of plasma isoflavone concentrations did not differ between the cases and controls. No statistically significant associations of genistein, daidzein, glycitein, and equol with primary liver cancer risk were found in either women or men.

CONCLUSIONS

In middle-aged Japanese women and men with hepatitis virus infection, plasma isoflavones were unassociated with the occurrence of primary liver cancer.

IMPACT

The role of isoflavones in liver carcinogenesis merits further study using both biomarkers and data on dietary intake of isoflavones. Cancer Epidemiol Biomarkers Prev; 24(3); 532-7. ©2014 AACR.