Soy and soy isoflavones in prostate cancer: a systematic review and meta-analysis of randomized controlled trials

The potential health effects of dietary phytoestrogens

Phytoestrogens are plant-derived dietary compounds with structural similarity to 17-β-oestradiol (E2), the primary female sex hormone. This structural similarity to E2 enables phytoestrogens to cause (anti)oestrogenic effects by binding to the oestrogen receptors. The aim of the present review is to present a state-of-the-art overview of the potential health effects of dietary phytoestrogens. Various beneficial health effects have been ascribed to phytoestrogens, such as a lowered risk of menopausal symptoms like hot flushes and osteoporosis, lowered risks of cardiovascular disease, obesity, metabolic syndrome and type 2 diabetes, brain function disorders, breast cancer, prostate cancer, bowel cancer and other cancers. In contrast to these beneficial health claims, the (anti)oestrogenic properties of phytoestrogens have also raised concerns since they might act as endocrine disruptors, indicating a potential to cause adverse health effects. The literature overview presented in this paper illustrates that several potential health benefits of phytoestrogens have been reported but that, given the data on potential adverse health effects, the current evidence on these beneficial health effects is not so obvious that they clearly outweigh the possible health risks. Furthermore, the data currently available are not sufficient to support a more refined (semi) quantitative risk-benefit analysis. This implies that a definite conclusion on possible beneficial health effects of phytoestrogens cannot be made.

LINKED ARTICLES

This article is part of a themed section on Principles of Pharmacological Research of Nutraceuticals. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.11/issuetoc.

Does soy protein affect circulating levels of unbound IGF-1?

INTRODUCTION

Despite the enormous amount of research that has been conducted on the role of soyfoods in the prevention and treatment of chronic disease, the mechanisms by which soy exerts its physiological effects are not fully understood. The clinical data show that neither soyfoods nor soy protein nor isoflavones affect circulating levels of reproductive hormones in men or women. However, some research suggests that soy protein, but not isoflavones, affects insulin-like growth factor I (IGF-1).

METHODS

Since IGF-1 may have wide-ranging physiological effects, we sought to determine the effect of soy protein on IGF-1 and its major binding protein insulin-like growth factor-binding protein (IGFBP-3). Six clinical studies were identified that compared soy protein with a control protein, albeit only two studies measured IGFBP-3 in addition to IGF-1.

RESULTS

Although the data are difficult to interpret because of the different experimental designs employed, there is some evidence that large amounts of soy protein (>25 g/day) modestly increase IGF-1 levels above levels observed with the control protein.

CONCLUSION

The clinical data suggest that a decision to incorporate soy into the diet should not be based on its possible effects on IGF-1.

Reporting and methodological quality of meta-analyses in urological literature

Purpose

To assess the overall quality of published urological meta-analyses and identify predictive factors for high quality.

Materials and Methods

We systematically searched PubMed to identify meta-analyses published from January 1st, 2011 to December 31st, 2015 in 10 predetermined major paper-based urology journals. The characteristics of the included meta-analyses were collected, and their reporting and methodological qualities were assessed by the PRISMA checklist (27 items) and AMSTAR tool (11 items), respectively. Descriptive statistics were used for individual items as a measure of overall compliance, and PRISMA and AMSTAR scores were calculated as the sum of adequately reported domains. Logistic regression was used to identify predictive factors for high qualities.

Results

A total of 183 meta-analyses were included. The mean PRISMA and AMSTAR scores were 22.74 ± 2.04 and 7.57 ± 1.41, respectively. PRISMA item 5, protocol and registration, items 15 and 22, risk of bias across studies, items 16 and 23, additional analysis had less than 50% adherence. AMSTAR item 1, “a priori” design, item 5, list of studies and item 10, publication bias had less than 50% adherence. Logistic regression analyses showed that funding support and “a priori” design were associated with superior reporting quality, following PRISMA guideline and “a priori” design were associated with superior methodological quality.

Conclusions

Reporting and methodological qualities of recently published meta-analyses in major paper-based urology journals are generally good. Further improvement could potentially be achieved by strictly adhering to PRISMA guideline and having “a priori” protocol.

Legume bioactive compounds: influence of rhizobial inoculation

Legumes consumption has been recognized as beneficial for human health, due to their content in proteins, fiber, minerals and vitamins, and their cultivation as beneficial for sustainable agriculture due to their ability to fix atmospheric nitrogen in symbiosis with soil bacteria known as rhizobia. The inoculation with these baceria induces metabolic changes in the plant, from which the more studied to date are the increases in the nitrogen and protein contents, and has been exploited in agriculture to improve the crop yield of several legumes. Nevertheless, legumes also contain several bioactive compounds such as polysaccharides, bioactive peptides, isoflavones and other phenolic compounds, carotenoids, tocopherols and fatty acids, which makes them functional foods included into the nutraceutical products. Therefore, the study of the effect of the rhizobial inoculation in the legume bioactive compounds content is gaining interest in the last decade. Several works reported that the inoculation of different genera and species of rhizobia in several grain legumes, such as soybean, cowpea, chickpea, faba bean or peanut, produced increases in the antioxidant potential and in the content of some bioactive compounds, such as phenolics, flavonoids, organic acids, proteins and fatty acids. Therefore, the rhizobial inoculation is a good tool to enhance the yield and quality of legumes and further studies on this field will allow us to have plant probiotic bacteria that promote the plant growth of legumes improving their functionality.

Influence of testosterone on phase II metabolism and availability of soy isoflavones in male Wistar rats

Genistein and daidzein are the main isoflavones in soy. Their potential beneficial or adverse effects in males like the prevention of prostate cancer or the impact on reproductive functions are controversially discussed. Major determinants of their bioactivity are the absorption and biotransformation of isoflavones. In this study, we focused on the influence of testosterone on plasma availability and phase II metabolism of isoflavones. Male Wistar rats, receiving an isoflavones rich diet, were randomized into three groups: Two groups were orchiectomized (ORX) at postnatal day (PND) 80 and treated for 11 days with testosterone propionate (TP) (ORX TP group) or a vehicle (ORX group) after a 7 days lasting hormonal decline. The third group served as control and remained intact. Rats were sacrificed at PND 98. ORX rats had reduced isoflavones plasma levels. Differently regulated mRNA expressions of transporters relevant for transport of phase II metabolites in liver and kidney may be responsible for this reduction, more precisely Slc10a1 and Slc21a1 in kidney as well as Slc22a8 in liver. While main phase II metabolites in intact rats were disulfates and sulfoglucuronides, the amount of sulfate conjugates was significantly diminished by ORX. In accordance with that, mRNA expression of different sulfotransferases was reduced in liver by ORX. The observed effects could be almost restored by TP treatment. In conclusion, testosterone, and likely further androgens, has a huge impact on phase II metabolism and availability of isoflavones by influencing the expression of different sulfotransferases and transporters.

An updated review of dietary isoflavones: Nutrition, processing, bioavailability and impacts on human health

Isoflavones (genistein, daidzein, and glycitein) are bioactive compounds with mildly estrogenic properties and often referred to as phytoestrogen. These are present in significant quantities (up to 4-5 mg·g^-1 on dry basis) in legumes mainly soybeans, green beans, mung beans. In grains (raw materials) they are present mostly as glycosides, which are poorly absorbed on consumption. Thus, soybeans are processed into various food products for digestibility, taste and bioavailability of nutrients and bioactives. Main processing steps include steaming, cooking, roasting, microbial fermentation that destroy protease inhibitors and also cleaves the glycoside bond to yield absorbable aglycone in the processed soy products, such as miso, natto, soy milk, tofu; and increase shelf lives. Processed soy food products have been an integral part of regular diets in many Asia-Pacific countries for centuries, e.g. China, Japan and Korea. However, in the last two decades, there have been concerted efforts to introduce soy products in western diets for their health benefits with some success. Isoflavones were hailed as magical natural component that attribute to prevent some major prevailing health concerns. Consumption of soy products have been linked to reduction in incidence or severity of chronic diseases such as cardiovascular, breast and prostate cancers, menopausal symptoms, bone loss, etc. Overall, consuming moderate amounts of traditionally prepared and minimally processed soy foods may offer modest health benefits while minimizing potential for any adverse health effects.

Dietary phytochemical intake from foods and health outcomes: a systematic review protocol and preliminary scoping

INTRODUCTION

Dietary phytochemicals are found in plant-based foods such as fruits, vegetables and grains and may be categorised in a nested hierarchical manner with many hundred individual phytochemicals identified to date. To associate phytochemical intakes with positive health outcomes, a fundamental step is to accurately estimate the dietary phytochemical intake from foods reported. The purpose of this systematic review protocol is to describe the process to be undertaken to summarise the evidence for food-based dietary phytochemical intakes and health outcomes for adults.

METHODS AND ANALYSIS

The review will be undertaken following the PRISMA guidelines and the Cochrane Handbook for Systematic Reviews of Interventions using the Review Manager software. Phytochemical subclasses (phenolic acids, flavanols, etc) will be used to search for relevant studies using the Web of Science and Scopus scientific databases. The retrieved studies will be screened based on inclusion of natural whole food items and health outcomes. Phytochemical studies related to cardiovascular disease, cancer, overweight, glucose tolerance, digestive, reproductive, macular and bone health and mental disorders, fatigue and immunity will be examined based on prior scoping. The evidence will be aggregated by the food types and health outcomes. Comparison of differences in the outcomes for randomised controlled trials and observational studies will be undertaken. The strength of the review lies in its focus on whole food items and health conditions rather than one type of phytochemical related to one single health condition. Subgroup and sensitivity analyses will be conducted where an adequate number of publications are found per phytochemical subclass.

DISSEMINATION

By comparing the outcomes from experimental and observational studies, the review will determine whether the overall conclusions related to the phytochemical subclasses are the same between study types for the identified health conditions. This is useful to public health policymakers and health professionals alike.

TRIAL REGISTRATION NUMBER

#CRD42014015610.

Isoflavones and Prostate Cancer: A Review of Some Critical Issues

Objective:

The purpose of this review is to discuss some critical issues of isoflavones protective against the development of prostate cancer (PCa).

Data Sources:

Data cited in this review were obtained primarily from PubMed and Embase from 1975 to 2015.

Study Selection:

Articles were selected with the search terms “isoflavone”, “Phytoestrogen”, “soy”, “genistin”, and “PCa”.

Results:

Isoflavones do not play an important role on prostate-specific antigen levels reduction in PCa patients or healthy men. The effect of isoflavones on sex hormone levels and PCa risk may be determined by equol converting bacteria in the intestine, specific polymorphic variation and concentrations of isoflavones. The intake of various types of phytoestrogens with lower concentrations in the daily diet may produce synergistic effects against PCa. Moreover, prostate tissue may concentrate isoflavones to potentially anti-carcinogenic levels. In addition, it is noteworthy that isoflavones may act as an agonist in PCa.

Conclusions:

Isoflavones play a protective role against the development of PCa. However, careful consideration should be given when isoflavones are used in the prevention and treatment of PCa.

Soy-Based Therapeutic Baby Formulas: Testable Hypotheses Regarding the Pros and Cons

Soy-based infant formulas have been consumed in the United States since 1909, and currently constitute a significant portion of the infant formula market. There are efforts underway to generate genetically modified soybeans that produce therapeutic agents of interest with the intent to deliver those agents in a soy-based infant formula platform. The threefold purpose of this review article is to first discuss the pros and cons of soy-based infant formulas, then present testable hypotheses to discern the suitability of a soy platform for drug delivery in babies, and finally start a discussion to inform public policy on this important area of infant nutrition.

Partial improvements in the flavor quality of soybean seeds using intercropping systems with appropriate shading

The profiles of isoflavone and fatty acids constitute important quality traits in soybean seeds, for making soy-based functional food products, due to their important contributions to the flavor and nutritional value of these products. In general, the composition of these constituents in raw soybeans is affected by cultivation factors, such as sunlight; however, the relationship of the isoflavone and fatty acid profiles with cultivation factors is not well understood. This study evaluated the isoflavone and fatty acid profiles in soybeans grown under a maize-soybean relay strip intercropping system with different row spacings, and with changes in the photosynthetic active radiation (PAR) transmittance. The effects of PAR on the isoflavone and fatty acid contents were found to be quadratic. Appropriate intercropping shading may reduce the bitterness of soybeans caused by soy aglycone and could improve their fatty acid composition.

Equol inhibits prostate cancer growth through degradation of androgen receptor by S-phase kinase-associated protein 2

Chemopreventive and potential therapeutic effects of soy isoflavones have been shown to be effective in numerous preclinical studies as well as clinical studies in prostate cancer. Although the inhibition of androgen receptor signaling has been supposed as one mechanism underlying their effects, the precise mechanism of androgen receptor inhibition remains unclear. Thus, this study aimed to clarify their mechanism. Among soy isoflavones, equol suppressed androgen receptor as well as prostate-specific antigen expression most potently in androgen-dependent LNCaP cells. However, the inhibitory effect on androgen receptor expression and activity was less prominent in castration-resistant CxR and 22Rv1 cells. Consistently, cell proliferation was suppressed and cellular apoptosis was induced by equol in LNCaP cells, but less so in CxR and 22Rv1 cells. We revealed that the proteasome pathway through S-phase kinase-associated protein 2 (Skp2) was responsible for androgen receptor suppression. Taken together, soy isoflavones, especially equol, appear to be promising as chemopreventive and therapeutic agents for prostate cancer based on the fact that equol augments Skp2-mediated androgen receptor degradation. Moreover, because Skp2 expression was indicated to be crucial for the effect of soy isoflavones, soy isoflavones may be applicable for precancerous and cancerous prostates.

Is There a Future for Chemoprevention of Prostate Cancer?

The outcome of the Selenium and Vitamin E Cancer Prevention Trial, demonstrating harm and no preventive activity of selenomethionine and α-tocopherol for prostate cancer, and the lack of approval by the FDA for the use of 5α-reductase inhibitors to prevent prostate cancer have cast doubt about the future of chemoprevention of prostate cancer. This article attempts to critically assess whether the notion that chemoprevention of prostate cancer has no future is warranted. Risk of prostate cancer is modifiable and chemoprevention of prostate cancer, particularly fatal/lethal cancer, is both needed and possible. However, the approach to prostate cancer-chemopreventive agent development has not followed a rational and systematic process. To make progress, the following steps are necessary: (i) identification of intermediate biomarkers predictive of fatal/lethal disease; (ii) development of a rational approach to identification of candidate agents, including high-throughput screening and generation of information on mechanism and biology of candidate agents and potential molecular targets; and (iii) systematic evaluation of the predictive value of preclinical models, phase II trials, and intermediate biomarkers for the outcome of phase III trials. New phase III trials should be based on adequate preclinical and phase II studies. Cancer Prev Res; 9(8); 642-7. ©2016 AACR.

Phytotherapeutic interventions in the management of biochemically recurrent prostate cancer: a systematic review of randomised trials

OBJECTIVE

To evaluate the evidence from randomised trials for the efficacy and safety of phytotherapeutic interventions in the management of biochemically recurrent (BCR) prostate cancer, indicated by prostate-specific antigen (PSA) progression, numbers progressing to/time to initiation of androgen-deprivation therapy or salvage therapy.

PATIENTS AND METHODS

MEDLINE (Ovid), EMBASE (Ovid), AMED (Ovid), CINAHL (EBSCO) and the Cochrane Library databases were searched. Clinical trials investigating phytotherapeutic interventions as dietary supplements or dietary components, including multi-component herbal formulations, in men with BCR prostate cancer were located. Eight of nine authors contacted for further information responded. Methodological quality was assessed using the Cochrane Collaboration's risk of bias assessment tool. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement for reporting systematic reviews was followed.

RESULTS

Of 23 full-text articles assessed for eligibility, five met the criteria for inclusion. Two studies were placebo controlled; two were active control trials; and one a high-/low-dose trial. The interventions were administered as isolated phytochemicals (sulphoraphane), phytotherapeutic extracts [Pomi-T (pomegranate, turmeric, green tea and broccoli sprout extract), soy, lycopene, and POMx (pomegranate extract)], or plant-derived dietary items (soy and lycopene). All studies found serum PSA levels to stabilise, decrease or rise more slowly in a significant number of men, and three studies reported stabilising or lengthening of PSA-doubling time. Studies were generally of good quality, but sample sizes were predominantly small, and durations short.

CONCLUSIONS

High-quality studies in this area are lacking. Sulphoraphane, lycopene, soy isoflavones, POMx, and Pomi-T are safe and well tolerated. There is limited evidence that they can affect PSA dynamics. No recommendation can be made for the use of these agents in managing prostate cancer morbidity and mortality until high-quality, fully powered studies are available. Recommendations are made for improving reproducibility and translation of findings with regard to study population, study endpoints, design, and the reporting of phytotherapeutic interventions.

Soy Intake Is Associated With Lower Endometrial Cancer Risk: A Systematic Review and Meta-Analysis of Observational Studies

Epidemiologic studies reporting the effect of soy intake on endometrial cancer risk conveyed conflicting results. We systematically reviewed the literature to investigate whether there was an inverse relation between dietary soy intake and endometrial cancer risk. PubMed, EMBASE, the Cochrane Library, and 4 main Chinese literature databases were searched from their inception to August 25, 2015 for both case-control studies and cohort studies that assessed the effect of soy intake on endometrial cancer risk. Study-specific most-adjusted odds ratios (ORs) or relative risks (RRs) were combined by using fixed-effects or random-effects model to calculate pooled risk estimates (REs). A total of 10 epidemiologic studies were included in this meta-analysis, including 8 case-control studies and 2 prospective cohort studies. Dietary soy intake was inversely associated with endometrial cancer risk with an overall RE of 0.81 (95% CI: 0.72, 0.91). In subgroup analyses, a statistically significant protective effect of soy intake was found for unfermented soy food (RE: 0.81, 95% CI: 0.67, 0.97), postmenopausal women (RE: 0.76, 95% CI: 0.61, 0.95), and Asian (RE: 0.79, 95% CI: 0.66, 0.95) and non-Asian population (RE: 0.83, 95% CI: 0.71, 0.96). Current evidence indicates that soy food intake is associated with lower endometrial cancer risk. Further larger cohort studies are warranted to fully clarify such an association.

Synergistic Effects of Dietary Natural Products as Anti-Prostate Cancer Agents

This review is to describe synergistic effects of various combinations of dietary natural products including curcumin, quercetin, soybean isoflavones, silibinin, and EGCG that have potential for the treatment of prostate cancer. These data can provide valuable insights into the future rational design and development of synergistic and/or hybrid agents for potential treatment of prostate cancer.

A systematic review of dietary, nutritional, and physical activity interventions for the prevention of prostate cancer progression and mortality

PURPOSE

Given the long-term, although potentially fatal, nature of prostate cancer, there is increasing observational evidence for the reduction in disease progression and mortality through changes in lifestyle factors.

METHODS

We systematically reviewed dietary, nutritional, and physical activity randomized interventions aimed at modifying prostate cancer progression and disease-specific mortality, including a detailed assessment of risk of bias and methodological quality.

RESULTS

Forty-four randomized controlled trials of lifestyle interventions, with prostate cancer progression or mortality outcomes, were identified. Substantial heterogeneity of the data prevented a meta-analysis. The included trials involved 3,418 prostate cancer patients, median 64 men per trial, from 13 countries. A trial of a nutritional supplement of pomegranate seed, green tea, broccoli, and turmeric; a trial comparing flaxseed, low-fat diet, flaxseed, and low-fat diet versus usual diet; and a trial supplementing soy, lycopene, selenium, and coenzyme Q10, all demonstrated beneficial effects. These trials were also assessed as having low risk of bias and high methodological quality (as were seven other trials with no evidence of benefit). The remaining trials were either underpowered, at high or unclear risk of bias, inadequately reported, of short duration or measured surrogate outcomes of unproven relationship to mortality or disease progression, which precluded any benefits reported being reliable.

CONCLUSION

Large, well-designed randomized trials with clinical endpoints are recommended for lifestyle modification interventions.

Consumption of soy isoflavone enriched bread in men with prostate cancer is associated with reduced proinflammatory cytokines and immunosuppressive cells

We hypothesized that soy phytochemicals may have immunomodulatory properties that may affect prostate carcinogenesis and progression. A randomized, phase II trial was conducted in 32 patients with prostate cancer with asymptomatic biochemical recurrence but no measurable disease on standard staging studies. Patients were randomized to two slices of soy bread (34 mg isoflavones/slice) or soy bread containing almond powder daily as a source of β-glucosidase. Flow cytometry and bioplex assays were used to measure cytokines or immune cell phenotype in blood at baseline (day 0) and following intervention (day 56). Adequate blood samples were available at enrollment and day 56 and evaluated. Multiple plasma cytokines and chemokines were significantly decreased on day 56 versus baseline. Subgroup analysis indicated reduced TH1 (P = 0.028) and myeloid-derived suppressor cell (MDSC)-associated cytokines (P = 0.035). TH2 and TH17 cytokines were not significantly altered. Phenotypic analysis revealed no change in CD8(+) or CD4(+) T cells but showed increased CD56(+) natural killer (NK) cells (P = 0.038). The percentage of cells with a T regulatory cell phenotype (CD4(+)CD25(+)FoxP3(+)) was significantly decreased after 56 days of soy bread (P = 0.0136). Significantly decreased monocytic (CD33(+)HLADR(neg)CD14(+)) MDSC were observed in patients consuming soy bread (P = 0.0056). These data suggest that soy bread modulates systemic soluble and cellular biomarkers consistent with limiting inflammation and suppression of MDSCs. Additional studies to elucidate impact on the carcinogenic process or as a complement to immune-based therapy are required.

Does night-shift work increase the risk of prostate cancer? a systematic review and meta-analysis

Background

Night-shift work is suggested to be associated with an increased risk of breast cancer, but its association with prostate cancer is still controversial. We examined this association by conducting a systematic review and meta-analysis.

Methods

Studies were identified by searching PubMed, EMBASE, Ovid, Web of Science, the Cochrane register, and the China National Knowledge Infrastructure databases through December 25, 2014. Summary relative risks (SRRs) with their corresponding 95% confidence intervals (CIs) were calculated using a random effects or fixed effects model. Heterogeneity and publication bias were also evaluated.

Results

A total of 2,459,845 individuals from eight published studies were included in this meta-analysis. Analysis of all studies suggested that night-shift work was associated with a significantly increased risk of prostate cancer (RR: 1.24, 95% CI: 1.05–1.46; P=0.011). Sensitivity analysis showed that the association remained significant when repeating the analysis after removing one study each time. Dose–response meta-analysis suggested that an increase in night-shift work of 5 years duration was statistically significantly associated with a 2.8% (95% CI: 0.3, 5.4%, P=0.030) increase in the risk of prostate cancer. There was no significant publication bias.

Conclusion

Based on a meta-analysis, night-shift work is associated with an increased risk of prostate cancer. Because of the limited number of included studies and the large level of heterogeneity, further well-designed studies are still warranted to confirm the findings of our analysis.

Lifestyle and dietary factors in relation to prostate cancer risk

The aim of the present study was to determine the association between the socio-demographic, lifestyle factors, and dietary habits with the risk of prostate cancer (PC) in a case-control study of Spanish men. None of the socio-demographic, lifestyle or dietetic variables was found predictors of PC risk. Body mass index was associated with an increased risk for aggressive PC and fruit consumption with lower Gleason scores, thus less aggressive cancers. Nonetheless, after applying Bonferroni correction, these variables were not still associated with PC aggressiveness. More adequately, powered epidemiological studies that measure the effect of lifestyle and dietary intake in PC risk and aggressiveness are warranted to further elucidate the role of these modifiable factors on PC etiology.

Genome-wide DNA methylation modified by soy phytoestrogens: role for epigenetic therapeutics in prostate cancer?

In prostate cancer, DNA methylation is significantly associated with tumor initiation, progression, and metastasis. Previous studies have suggested that soy phytoestrogens might regulate DNA methylation at individual candidate gene loci and that they play a crucial role as potential therapeutic agents for prostate cancer. The purpose of our study was to examine the modulation effects of phytoestrogens on a genome-wide scale in regards to DNA methylation in prostate cancer. Prostate cancer cell lines DU-145 and LNCaP were treated with 40 μM of genistein and 110 μM of daidzein. DNMT inhibitor 5-azacytidine (2 μM) and the methylating agent budesonide (2 μM) were used to compare their demethylation/methylation effects with phytoestrogens. The regulatory effects of phytoestrogens on DNA methylation were analyzed by using a methyl-DNA immunoprecipitation method coupled with Human DNA Methylation Microarrays (MeDIP-chip). We observed that the methylation profiles of 58 genes were altered by genistein and daidzein treatments in DU-145 and LNCaP prostate cancer cells. In addition, the methylation frequencies of the MAD1L1, TRAF7, KDM4B, and hTERT genes were remarkably modified by genistein treatment. Our results suggest that the modulation effects of phytoestrogens on DNA methylation essentially lead to inhibition of cell growth and induction of apoptosis. Genome-wide methylation profiling reported here suggests that epigenetic regulation mechanisms and, by extension, epigenetics-driven novel therapeutic candidates warrant further consideration in future "omics" studies of prostate cancer.

Nutrition, dietary interventions and prostate cancer: the latest evidence

Prostate cancer (PCa) remains a leading cause of mortality in US men and the prevalence continues to rise world-wide especially in countries where men consume a 'Western-style' diet. Epidemiologic, preclinical and clinical studies suggest a potential role for dietary intake on the incidence and progression of PCa. 'This minireview provides an overview of recent published literature with regard to nutrients, dietary factors, dietary patterns and PCa incidence and progression. Low carbohydrates intake, soy protein, omega-3 (w-3) fat, green teas, tomatoes and tomato products and zyflamend showed promise in reducing PCa risk or progression. A higher saturated fat intake and a higher β-carotene status may increase risk. A 'U' shape relationship may exist between folate, vitamin C, vitamin D and calcium with PCa risk. Despite the inconsistent and inconclusive findings, the potential for a role of dietary intake for the prevention and treatment of PCa is promising. The combination of all the beneficial factors for PCa risk reduction in a healthy dietary pattern may be the best dietary advice. This pattern includes rich fruits and vegetables, reduced refined carbohydrates, total and saturated fats, and reduced cooked meats. Further carefully designed prospective trials are warranted.

A hypothesis regarding the molecular mechanism underlying dietary soy-induced effects on seizure propensity

Numerous neurological disorders including fragile X syndrome, Down syndrome, autism, and Alzheimer’s disease are co-morbid with epilepsy. We have observed elevated seizure propensity in mouse models of these disorders dependent on diet. Specifically, soy-based diets exacerbate audiogenic-induced seizures in juvenile mice. We have also found potential associations between the consumption of soy-based infant formula and seizure incidence, epilepsy comorbidity, and autism diagnostic scores in autistic children by retrospective analyses of medical record data. In total, these data suggest that consumption of high levels of soy protein during postnatal development may affect neuronal excitability. Herein, we present our theory regarding the molecular mechanism underlying soy-induced effects on seizure propensity. We hypothesize that soy phytoestrogens interfere with metabotropic glutamate receptor signaling through an estrogen receptor-dependent mechanism, which results in elevated production of key synaptic proteins and decreased seizure threshold.

Prostate cancer and the influence of dietary factors and supplements: a systematic review

Background

Prostate cancer is the second most common cause of cancer worldwide after lung cancer. There is increasing evidence that diet and lifestyle plays a crucial role in prostate cancer biology and tumourigenesis. Prostate cancer itself represents a good model of cancer in which to look for chemopreventive agents due to the high disease prevalence, slowly progressive nature, and long latency period. Dietary agents have gained considerable attention, often receiving much publicity in the media.

Aim

To review the key evidence available for potential chemopreventive nutrients.

Methods

The methodology for this review involved a PubMed search from 1990 to 2013 using the key-words “diet and prostate cancer”, “nutrition and prostate cancer”, “dietary factors and prostate cancer”, “prostate cancer epidemiology”, “prostate cancer prevention”, “prostate cancer progression”.

Results

Red meat, dietary fat and milk intake should be minimised as they appear to increase the risk of prostate cancer. Fruit and vegetables and polyphenols may be preventive in prostate cancer, but further studies are needed to draw more solid conclusions and to clarify their role in patients with an established diagnosis of prostate cancer. Selenium and vitamin supplements cannot be advocated for the prevention of prostate cancer and indeed higher doses may be associated with a worse prognosis. There is no specific evidence regarding benefits of probiotics or prebiotics in prostate cancer.

Conclusions

From the wealth of evidence available, many recommendations can be made although more randomised control trials are required. These need to be carefully designed due to the many confounding factors and heterogeneity of the population.