Soy for breast cancer survivors: a critical review of the literature

Changes in the consumption of isoflavones, omega-6, and omega-3 fatty acids in women with metastatic breast cancer adopting a whole-food, plant-based diet: post-hoc analysis of nutrient intake data from an 8-week randomized controlled trial

Background

Diets rich in minimally processed plant-based foods are recommended to breast cancer patients, and some may have an interest in whole-food, plant-based (WFPB) diets that avoid animal-based foods, added fats, and refined sugars. Within WFPB diets, the intakes of isoflavones, omega-6 polyunsaturated fatty acids (n-6 PUFAs), and omega-3 polyunsaturated FAs (n-3 PUFAs), which have been discussed in reference to breast cancer outcomes, have not been well characterized.

Methods

Women with stage IV breast cancer on stable therapy were randomized 2:1 into (1) a WFPB intervention (N = 21) or (2) usual care (N = 11) for 8 weeks. Three meals per day were provided. Outcomes presented here include dietary intake of isoflavones, n-3 and n-6- PUFAs, which were assessed using three-day food records at baseline and 8 weeks. Baseline and 8-week mean intake within groups were compared using the Wilcoxon signed-rank test and between control and intervention groups by a two-sample t-test.

Results

The WFPB intervention participants increased their daily consumption of total isoflavones from a mean of 0.8 mg/day to 14.5 mg/day (p < 0.0001) and decreased the n-6:n-3 ratio of their diet from a mean of 9.3 to 3.7 (p < 0.0001). Within the WFPB group, linoleic acid (n-6 PUFA) consumption decreased by a mean of 3.8 g (p = 0.0095), from 12.8 g/day to 9.0 g/day; total n-3 PUFA consumption increased by a mean of 1.1 g (p = 0.0005), from 1.6 g/day to 2.7 g/day.

Conclusion

Transitioning to a WFPB diet resulted in significantly increased isoflavone intake and decreased n-6:n-3 ratio in women with breast cancer.

Reproductive late effects after hematopoietic stem cell transplant in pediatric, adolescent, and young adult cancer survivors

Reproductive late effects after hematopoietic stem cell transplant can have a significant impact on cancer survivors' quality of life. Potential late effects include gonadal insufficiency, genital graft-versus-host disease, uterine injury, psychosexual dysfunction, and an increased risk of breast and cervical cancer in patients treated with total body irradiation. Despite guidelines, screening and treatment are not standardized among at-risk patients. Provider barriers include lack of knowledge of at-risk therapies and evidenced-based guidelines. Patient barriers include a reluctance to report symptoms and lack of awareness of treatment options. System barriers include inefficient implementation of screening tools and poor dissemination of guidelines to providers who serve as the medical home for survivors. This review guides the clinician in identifying and managing reproductive late effects after hematopoietic stem cell transplant to improve outcomes.

Improvement of Soybean; A Way Forward Transition from Genetic Engineering to New Plant Breeding Technologies

Soybean is considered one of the important crops among legumes. Due to high nutritional contents in seed (proteins, sugars, oil, fatty acids, and amino acids), soybean is used globally for food, feed, and fuel. The primary consumption of soybean is vegetable oil and feed for chickens and livestock. Apart from this, soybean benefits soil fertility by fixing atmospheric nitrogen through root nodular bacteria. While conventional breeding is practiced for soybean improvement, with the advent of new biotechnological methods scientists have also engineered soybean to improve different traits (herbicide, insect, and disease resistance) to fulfill consumer requirements and to meet the global food deficiency. Genetic engineering (GE) techniques such as transgenesis and gene silencing help to minimize the risks and increase the adaptability of soybean. Recently, new plant breeding technologies (NPBTs) emerged such as zinc-finger nucleases, transcription activator-like effector nucleases, and Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR/Cas9), which paved the way for enhanced genetic modification of soybean. These NPBTs have the potential to improve soybean via gene functional characterization precision genome engineering for trait improvement. Importantly, these NPBTs address the ethical and public acceptance issues related to genetic modifications and transgenesis in soybean. In the present review, we summarized the improvement of soybean through GE and NPBTs. The valuable traits that have been improved through GE for different constraints have been discussed. Moreover, the traits that have been improved through NPBTs and potential targets for soybean improvements via NPBTs and solutions for ethical and public acceptance are also presented.

Impacts of nutritive and bioactive compounds on cancer development and therapy

For persons who survive with progressive cancer, nutritional therapy and exercise may be significant factors to improve the health condition and life quality of cancer patients. Nutritional therapy and medications are essential to managing progressive cancer. Cancer survivors, as well as cancer patients, are mostly extremely encouraged to search for knowledge about the selection of diet, exercise, and dietary supplements to recover as well as maintain their treatment consequences, living quality, and survival of patients. A healthy diet plays an important role in cancer treatment. Different articles are studied to collect information and knowledge about the use of nutrients in cancer treatment as well as cancer prevention. The report deliberates nutrition and exercise strategies during the range of cancer care, emphasizing significant concerns during treatment of cancer and for patients of advanced cancer, but concentrating mostly on the requirements of the population of persons who are healthy or who have constant disease following their repossession from management. It also deliberates choice nutrition and exercise problems such as dietary supplements, food care, food selections, and weight; problems interrelated to designated cancer sites, and common questions about diet, and cancer survival. Decrease the side effects of medicines both during and after treatment.

Mechanism of Soy Isoflavone Daidzein-Induced Female-Specific Anorectic Effect

Epidemiological studies suggest that regular intake of soy isoflavone exerts a preventive effect on postmenopausal obesity and other forms of dysmetabolism. Estrogens inhibit eating behavior. Soy isoflavones may act as estrogen agonist in estrogen-depleted conditions, whereas they may either act as an estrogen antagonist or be ineffective in estrogen-repleted conditions. We investigated the effects of dietary soy isoflavone on food intake under various estrogen conditions using male, ovariectomized (OVX), and non-OVX female rats, and compared the effects with those of estradiol. We found that soy isoflavones reduced food intake in females specifically, regardless of whether ovariectomy had been performed, whereas subcutaneous implantation of estradiol pellet did not reduce food intake in intact female rats, but did so in OVX female and male rats. Contrary to this hypothesis, the reduction in food intake may not be caused by the estrogenic properties of soy isoflavones. It is of great interest to understand the mechanisms underlying the anorectic effects of soy isoflavones. In this non-systematic review, we summarize our recent studies that have investigated the bioactive substances of anorectic action, pharmacokinetic properties of soy isoflavones, and the modification of central and peripheral signals regulating appetite by soy isoflavones, and selected studies that were identified via database mining.

Development of Nano Soy Milk through Sensory Attributes and Consumer Acceptability

Nanotechnology is currently applied in food processing and packaging in the food industry. Nano encapsulation techniques could improve sensory perception and nutrient absorption. The purpose of this study was to identify the sensory characteristics and consumer acceptability of three types of commercial and two types of laboratory-developed soy milk. A total of 20 sensory attributes of the five different soy milk samples, including appearance, smell (odor), taste, flavor, and mouthfeel (texture), were developed. The soy milk samples were evaluated by 100 consumers based on their overall acceptance, appearance, color, smell (odor), taste, flavor, mouthfeel (texture), goso flavor (nuttiness), sweetness, repeated use, and recommendation. One-way analysis of variance (ANOVA), principal component analysis (PCA), and partial least square regression (PLSR) were used to perform the statistical analyses. The SM_D sample generally showed the highest scores for overall liking, flavor, taste, mouthfeel, sweetness, repeated consumption, and recommendation among all the consumer samples tested. Consumers preferred sweet, goso (nuttiness), roasted soybean, and cooked soybean (nuttiness) attributes but not grayness, raw soybean flavor, or mouthfeel. Sweetness was closely related to goso (nuttiness) odor and roasted soybean odor and flavor based on partial least square regression (PLSR) analysis. Determination of the sensory attributes and consumer acceptance of soymilk provides insight into consumer needs and desires along with basic data to facilitate the expansion of the consumer market.

Metabolic Engineering of Isoflavones: An Updated Overview

Isoflavones are ecophysiologically active secondary metabolites derived from the phenylpropanoid pathway. They were mostly found in leguminous plants, especially in the pea family. Isoflavones play a key role in plant-environment interactions and act as phytoalexins also having an array of health benefits to the humans. According to epidemiological studies, a high intake of isoflavones-rich diets linked to a lower risk of hormone-related cancers, osteoporosis, menopausal symptoms, and cardiovascular diseases. These characteristics lead to the significant advancement in the studies on genetic and metabolic engineering of isoflavones in plants. As a result, a number of structural and regulatory genes involved in isoflavone biosynthesis in plants have been identified and characterized. Subsequently, they were engineered in various crop plants for the increased production of isoflavones. Furthermore, with the advent of high-throughput technologies, the regulation of isoflavone biosynthesis gains attention to increase or decrease the level of isoflavones in the crop plants. In the review, we begin with the role of isoflavones in plants, environment, and its benefits in human health. Besides, the main theme is to discuss the updated research progress in metabolic engineering of isoflavones in other plants species and regulation of production of isoflavones in soybeans.

Cell Cycle Modulation of CHO-K1 Cells Under Genistein Treatment Correlates with Cells Senescence, Apoptosis and ROS Level but in a Dose-Dependent Manner

Purpose: Genistein, a soy isoflavone, exhibits a biphasic effect on cells proliferation with some different effects between ER-alpha and ER-beta. The objective of this present study is to determine the modulatory effect based on cell cycle progression under genistein treatment in combination with 17-β estradiol (E2) on CHO-K1 cells. Methods: The effect of genistein 0.1-100 µM on cells proliferation was examined by MTT assay. The modulation of genistein and estradiol (E2) on cell cycle and apoptosis were observed by using flowcytometry with PI and PI/AnnexinV staining, respectively. Moreover, the effect of genistein and E2 on senescence cells, and ROS level were determined by senescence-associated β-galactosidase (SA β-gal) staining and by using flowcytometry with 2', 7'-dichlorofluorescin diacetate (DCFDA) staining, respectively. The expression level of the cell cycle and senescence protein markers were observed by immunoblotting. Results: Single treatment of genistein at physiologically achievable (low) concentration (<2 µM) induced proliferation of CHO-K1 cells while at a pharmacological (high) concentration (50 and 100 µM) suppressed cells proliferation. Interestingly, treatment of genistein at the physiological concentration in combination with E2 for 24, 48 and 72 h decreased cells viability on CHO-K1 cells compared to untreated cells. Further analysis of the cells showed that 50 µM genistein induced G2/M phase accumulation and induced apoptosis. Moreover, genistein induced cell senescence and increased ROS level. Immunoblotting analysis showed the decreasing of ERalpha, Bcl2, and ppRb protein level upon treatment of 1 µM Gen and 1 nM E2. Conclusion: Our results suggest that the cell proliferation inhibitory mechanism of genistein at pharmacological concentration involved the induction of cell senescence, and the elevation of ROS level. Moreover, the decreased of cells proliferation upon treatment of physiological concentration of genistein in combination with E2 may be correlated with the alteration of ER expression.

Multicenter Randomized Controlled Trial of Omega-3 Fatty Acids Versus Omega-6 Fatty Acids for the Control of Cancer-Related Fatigue Among Breast Cancer Survivors

Background

Cancer-related fatigue (CRF) is a common side effect of adjuvant therapy and becomes a chronic problem for approximately one-third of survivors. Omega-3 polyunsaturated fatty acids (O3-PUFA) demonstrated preliminary antifatigue effects in previous research, but have not been investigated in fatigued cancer survivors.

Methods

Breast cancer survivors 4–36 months posttreatment with a CRF score of 4 or more of 10 using the symptom inventory (SI) were randomly assigned to O3-PUFA (fish oil, 6 g/d), omega-6 PUFA (O6-PUFA; soybean oil, 6 g/d), or a low-dose combination of O3-/O6-PUFA (3 g/d O3-PUFA and O6-PUFA) for 6 weeks. CRF was assessed by the SI (screening question), the Brief Fatigue Inventory, and the Multidimensional Fatigue Symptom Index. Protein and mRNA levels of inflammatory and antioxidant biomarkers, along with fatty acid and lipid levels, were assessed at baseline and week 6. Statistical tests were two-sided.

Results

A total of 108 breast cancer survivors consented; 97 subjects were randomly assigned and 81 completed the trial. The SI CRF score decreased by 2.51 points at week 6 with O6-PUFA and by 0.93 points with O3-PUFA, with statistically significant between-group difference (effect size = −0.86, P < .01). Similar changes were observed for the Brief Fatigue Inventory and Multidimensional Fatigue Symptom Index but were not statistically significant. Stratified analyses showed the largest benefit was observed in those with severe baseline CRF (≥7). Compared with O3-PUFA, O6-PUFA supplementation statistically significantly decreased proinflammatory markers in the TNF-α signaling pathway.

Conclusion

Contrary to our original hypothesis, O6-PUFA statistically significantly reduced CRF compared with O3-PUFA. Further research is needed to confirm these findings and to elucidate mechanisms of action.

Bioactivity of soy-based fermented foods: A review

For centuries, fermented soy foods have been dietary staples in Asia and, now, in response to consumer demand, they are available throughout the world. Fermentation bestows unique flavors, boosts nutritional values and increases or adds new functional properties. In this review, we describe the functional properties and underlying action mechanisms of soy-based fermented foods such as Natto, fermented soy milk, Tempeh and soy sauce. When possible, the contribution of specific bioactive components is highlighted. While numerous studies with in vitro and animal models have hinted at the functionality of fermented soy foods, ascribing health benefits requires well-designed, often complex human studies with analysis of diet, lifestyle, family and medical history combined with long-term follow-ups for each subject. In addition, the contribution of the microbiome to the bioactivities of fermented soy foods, possibly mediated through direct action or bioactive metabolites, needs to be studied. Potential synergy or other interactions among the microorganisms carrying out the fermentation and the host's microbial community may also contribute to food functionality, but the details still require elucidation. Finally, safety evaluation of fermented soy foods has been limited, but is essential in order to provide guidelines for consumption and confirm lack of toxicity.

Flavonoids in Cancer and Apoptosis

Cancer is the second leading cause of death globally. Although, there are many different approaches to cancer treatment, they are often painful due to adverse side effects and are sometimes ineffective due to increasing resistance to classical anti-cancer drugs or radiation therapy. Targeting delayed/inhibited apoptosis is a major approach in cancer treatment and a highly active area of research. Plant derived natural compounds are of major interest due to their high bioavailability, safety, minimal side effects and, most importantly, cost effectiveness. Flavonoids have gained importance as anti-cancer agents and have shown great potential as cytotoxic anti-cancer agents promoting apoptosis in cancer cells. In this review, a summary of flavonoids and their effectiveness in cancer treatment targeting apoptosis has been discussed.

Dietary intake of soy and cruciferous vegetables and treatment-related symptoms in Chinese-American and non-Hispanic White breast cancer survivors

PURPOSE

This project was undertaken to examine the association between dietary intake of soy or cruciferous vegetables and breast cancer treatment-related symptoms among Chinese-American (CA) and Non-Hispanic White (NHW) breast cancer survivors.

METHODS

This cross-sectional study included 192 CA and 173 NHW female breast cancer survivors (stages 0-III, diagnosed between 2006 and 2012) recruited from two California cancer registries, who had completed primary treatment. Patient-reported data on treatment-related symptoms and potential covariates were collected via telephone interviews. Dietary data were ascertained by mailed questionnaires. The outcomes evaluated were menopausal symptoms (hot flashes, night sweats, vaginal dryness, vaginal discharge), joint problems, fatigue, hair thinning/loss, and memory problems. Associations between soy and cruciferous vegetables and symptoms were assessed using logistic regression. Analyses were further stratified by race/ethnicity and endocrine therapy usage (non-user, tamoxifen, aromatase inhibitors).

RESULTS

Soy food and cruciferous vegetable intake ranged from no intake to 431 and 865 g/day, respectively, and was higher in CA survivors. Higher soy food intake was associated with lower odds of menopausal symptoms (≥ 24.0 vs. 0 g/day, OR 0.51, 95% CI 0.25, 1.03), and fatigue (≥ 24.0 vs. 0 g/day, OR 0.43, 95% CI 0.22, 0.84). However, when stratified by race/ethnicity, associations were statistically significant in NHW survivors only. Compared with low intake, higher cruciferous vegetable intake was associated with lower odds of experiencing menopausal symptoms (≥ 70.8 vs. < 33.0 g/day, OR 0.50, 95% CI 0.25, 0.97) in the overall population.

CONCLUSIONS

In this population of breast cancer survivors, higher soy and cruciferous vegetable intake was associated with less treatment-related menopausal symptoms and fatigue.

The history and basic science development of soy isoflavones

This review summarizes the 2016 NAMS/Pfizer-Wulf H. Utian Endowed Lecture that focused on the history and basic science of soy isoflavones. Described is a personal perspective of the background and history that led to the current interest in soy and isoflavones with a specific focus on the role that soy isoflavones play in the health of postmenopausal women. This overview covers the metabolism and physiological behavior of isoflavones, their biological properties that are of potential relevance to aging, issues related to the safety of soy isoflavones, and the role of the important intestinally derived metabolite S-(-)equol.

Influence of the addition of soy product and wheat fiber on rheological, textural, and other quality characteristics of pizza

The effect of partial replacement of wheat flour with soy paste and wheat fiber on rheological, textural, physicochemical, and organoleptic characteristics of an enriched pizza base (E) was investigated in comparison with those of a control pizza base (C). New ingredients (e.g., enriched cooked ham, whey cheese, and tomato sauce realized using food industry by-products) were also used in E pizza topping to further increase its nutritional properties. Enriched dough was developed first at a laboratory level. Large and small deformation, moisture, leavening activity, and metabolic heat were tested. On the final product, produced at the industrial level, textural, color, sensory, and nutritional analyses were performed. Preliminary rheological analysis was essential to evaluate the suitability of the new pizza to be processed at industrial level. Both pizza dough samples showed a solid elastic-like behavior; however, the addition of soy and fiber increased moisture content of E pizza, due to the water binding ability of soy protein and to the effect of fibers that also decreased E dough elasticity. No differences in extensibility between the two samples were observed, whereas significantly lower values of resistance to extension and dough force were shown in sample E. These differences were likely due to the presence of soy that interfere with gluten formation and to the dietary fibers that interact with water. Ingredients used in E pizza improved its nutritional quality increasing dietary fibers and protein, and decreasing saturated fatty acids and cholesterol content, which contributed to decrease energy value, in terms of kilocalorie reduction.

PRACTICAL APPLICATIONS

In this work, the effects of using new ingredients (e.g., soy paste, wheat fiber) on the rheological, textural, physicochemical, nutritional, and organoleptic characteristics of an enriched pizza type were investigated both at laboratory and industrial levels. The new pizza provides a product that combines solid technological performances, in terms of rheological properties and dough elasticity, with improved and balanced nutritional quality, thanks also to the ingredients used in the topping. Results demonstrate the possibility of obtaining new pizza products characterized by nutritional and sensorial properties tailored for different group of consumers.

The role of soybean extracts and isoflavones in hormone-dependent breast cancer: aromatase activity and biological effects

Estrogen receptor-positive (ER+) breast cancer is the most common cause of cancer death in women worldwide. Nowadays, the relationship between soya diet and breast cancer is controversial due to the unknown role of its isoflavones, genistein (G) and daidzein (D). In this work, we investigated not only the anti-tumor properties of a soybean extract (NBSE) but also whether the biotransformation of extract (BSE) by the fungus Aspergillus awamori increased its effectiveness. The BSE showed a stronger anti-aromatase activity and anti-proliferative efficacy in ER+ aromatase-overexpressing breast cancer cells. D and G were weak aromatase inhibitors, but inhibited cancer cell growth, being G the isoflavone that contributed to the BSE-induced effects. This work demonstrated that the biotransformation increased the anti-aromatase activity and the anti-tumoral efficacy of soybean extract in breast cancer cells. Moreover, it elucidated the potential use of soya in the prevention and/or treatment of ER+ breast cancer.

Proteins in Soy Might Have a Higher Role in Cancer Prevention than Previously Expected: Soybean Protein Fractions Are More Effective MMP-9 Inhibitors Than Non-Protein Fractions, Even in Cooked Seeds

The search for anticancer MMP-9 inhibitors (MMPIs) in food products has become a major goal for research. MMPIs in soy have been related only to saponins and isoflavones, but recently, low specific protein fractions in soybeans were shown to reduce MMP-9 activity as well. The present work aimed at comparing the MMPI potential of protein fractions (P) and non-protein fractions (NP) isolated from soybean seeds, before and after soaking and cooking, mimicking dietary exposures. Reverse and substrate zymography, as well as a fluoregenic DQ gelatin assay were used to evaluate MMP-9 activities. Colon cancer cell migration and proliferation was also tested in HT29 cells. Regarding MMP-9 inhibition, proteins in soy presented IC₅₀ values 100 times lower than non-protein extracts, and remained active after cooking, suggesting that proteins may be more effective MMP-9 inhibitors than non-protein compounds. Using the determined IC₅₀ concentrations, NP fractions were able to induce higher inhibitions of HT29 cell migration and proliferation, but not through MMP-9 inhibition, whilst protein fractions were shown to specifically inhibit MMP-9 activity. Overall, our results show that protein fractions in soybeans might have a higher role in soy-related cancer prevention as MMPIs than previously expected. Being nontoxic and active at lower concentrations, the discovery of these heat-resistant specific MMPI proteins in soy can be of significant importance for cancer preventive diets, particularly considering the increasing use of soy proteins in food products and the controversy around isoflavones amongst consumers.

The Phytoestrogen Genistein Affects Breast Cancer Cells Treatment Depending on the ERα/ERβ Ratio

Genistein (GEN) is a phytoestrogen found in soybeans. GEN exerts its functions through its interaction with the estrogen receptors (ER), ERα and ERβ, and we previously reported that the ERα/ERβ ratio is an important factor to consider in GEN-treated breast cancer cells. The aim of this study was to investigate the effects of GEN in breast cancer cells with different ERα/ERβ ratio: MCF-7 (high ratio), T47D (low ratio), and MCF-7 overexpressing ERβ (MCF7 + ERβ) treated with cisplatin (CDDP), paclitaxel (PTX) or tamoxifen (TAM). Cell viability, ROS production, autophagy, apoptosis, antioxidant enzymes protein levels, and cell cycle were analyzed. GEN treatment provoked an increase in cell viability in MCF-7 cells and in the antioxidant enzymes protein levels in combination with the cytotoxic agents, decreasing ROS production (CDDP + GEN and TAM+GEN) and autophagy (TAM + GEN) or apoptosis (CDDP + GEN and TAM + GEN). Moreover GEN treatment enhanced the cell cycle S phase entry in CDDP+GEN- and TAM + GEN-treated MCF-7 cells and, in the case of CDDP + GEN, increased the proportion of cells in the G2/M phase and decreased it in the subG0 /G1 phase. Otherwise, in the T47D and MCF7 + ERβ cells the combination of GEN with cytotoxic treatments did not cause significant changes in these parameters, even TAM + GEN-treated T47D cells showed less cell viability due to an increment in the autophagy. In conclusion, GEN consumption may be counterproductive in those patients receiving anticancer treatment with a high ERα/ERβ ratio diagnosed breast cancer and it could be harmless or even beneficial in those patients with a lower ERα/ERβ ratio breast cancer cells.

Carcinogenetic mechanisms of endocrine disruptors in female cancers (Review)

Endocrine disruptors (EDs) are pollutants that alter the endocrine system and are involved in carcinogenesis. EDs have multiple and complex levels of action. They can affect the synthesis, release and transport of natural hormones. In target tissues, EDs can reduce or increase the effects of natural hormones on their receptors and change signaling cascades. When ED exposure happens at critical periods of life, from embryo to puberty, they can act at doses considered safe for an adult. Furthermore, their epigenetic effects can also influence the cancer risk of future generations. The cancer mechanisms of known EDs are hereby reviewed, There are thousands of newly introduced substances whose potential endocrine-disrupting and cancer effects are completely unknown. Although there are still gaps in our knowledge, these data support the urgent need for health and environmental policies aimed at protecting the public and in particular, the developing fetus and women of reproductive age.

Impact of Elimination or Reduction of Dietary Animal Proteins on Cancer Progression and Survival: Protocol of an Online Pilot Cohort Study

Background

Current evidence suggests that the incidence of cancer is low in vegan populations, and experimental studies have revealed a significant role of dietary proteins in cancer development and progression. However, little data currently exists regarding the effect of a plant-based diet on the progression of diagnosed cancer.

Objective

The main objective of this study is to determine if a reduction or total elimination of animal protein from the diet can positively influence the outcome of an existing cancer and, in addition to standard oncological therapies, increase remission rates.

Methods

The primary aim of this online study is to test the effect on remission rates in cancer patients (primary outcome) with distinct self-selected dietary patterns (omnivore, lacto-ovo-vegetarian, vegan), and allow for an estimation of the effect size. Secondary outcomes are tumor behavior, relapse-free interval, therapies, therapy tolerability and side-effects, comorbidities, medication, quality of life, acceptance, and feasibility of the selected diet. Safety concerns exist for vegan diets (especially in cancer patients) and the study will carefully monitor for deterioration of health, tumor progression, or malnutrition. Furthermore, the study will evaluate the online portal as a study platform (technical and safety aspects, and sequence of displayed questionnaires) as well as the validity of self-reported and online-generated data.

Results

The study was performed between April, 2015 and June, 2016, and a preliminary evaluation of safety aspects was undertaken after June, 2016. Primary and secondary outcomes will be evaluated when the final patients complete the study in December, 2016.

Conclusions

This study will reveal information about the effects of dietary patterns on cancer disease and progression. The methodology of the study addresses several aspects and limitations of nutrition studies in cancer patients, such as precision of nutrition data, acceptance criteria, online methodology, and safety aspects.

ClinicalTrial

Clinicaltrials.gov NCT02437474; https://clinicaltrials.gov/ct2/show/NCT02437474 (Archived by WebCite at http://www.webcitation.org/6jL7UUCVq)

Long-term soy consumption and tumor tissue MicroRNA and gene expression in triple-negative breast cancer

BACKGROUND

Soy food intake may have protective effects against the risk for breast cancer, including estrogen receptor (ER)-negative breast cancer. However, the underlying molecular mechanisms remain unclear.

METHODS

To evaluate the association of soy intake with the expression of microRNAs (miRNAs) and genes in the tumor tissue of patients with triple-negative breast cancer (TNBC; ie, breast cancer lacking expression of ER, progesterone receptor, and human epidermal growth factor receptor 2), the expression of 800 miRNAs and 302 genes were measured with NanoString nCounter assays in formalin-fixed, paraffin-embedded tumor tissue from 272 TNBC patients. Soy intake during the 1-year period before the cancer diagnosis was assessed with a validated food-frequency questionnaire. The association of soy intake with the expression of miRNAs and genes was evaluated via linear regression analysis with adjustments for patient age and TNM stage.

RESULTS

A total of 14 miRNAs and 24 genes were significantly associated with soy food intake (P < .05): Thirteen of the 14 miRNAs (92.9%) and 9 of the 24 genes (37.5%), including tumor suppressors miR-29a-3p and IGF1R, showed overexpression for those women with high soy intake, whereas the remaining miRNAs and genes, including oncogenes KRAS and FGFR4, showed underexpression. Furthermore, cell growth-related genes showed a predominantly underexpression pattern according to a comparison of tumor samples from women with high soy food intake and samples from women with lower soy food intake.

CONCLUSIONS

This study suggests that long-term prediagnosis soy intake may lead to increased expression of tumor suppressors and decreased expression of oncogenes, especially cell growth-related genes, in breast tumor tissues. Cancer 2016;122:2544-51. © 2016 American Cancer Society.

Genistein induces apoptosis by the inactivation of the IGF-1R/p-Akt signaling pathway in MCF-7 human breast cancer cells

Genistein is an estrogenic soy-derived compound belonging to the isoflavone class and shows anti-cancer effects. However, the specific cell apoptosis mechanisms of genistein have not been fully understood. In this study, we investigated the specific cell apoptosis mechanisms of genistein and the potential involvement of the IGF1R-Akt-Bcl-2 and Bax-mediated pathways in human breast cancer cells in vitro. MCF-7 human breast cancer cells were treated with various concentrations of genistein, and cell proliferation was evaluated by the MTT assay. Morphological changes in treated cells were examined by Hoechst 33258 staining, and treated cells were examined by flow cytometry. The levels of IGF-1R, p-Akt, Bcl-2, and Bax protein expression and Bcl-2 and Bax mRNA expression were evaluated by western blot and RT-PCR, respectively. Genistein inhibited the proliferation of MCF-7 cells and induced cell apoptosis, as determined by Hoechst staining and flow cytometry analysis. Furthermore, genistein induced the inactivation of IGF-1R and p-Akt and downregulated the Bcl-2/Bax protein ratio. These results suggest that genistein inhibited cell proliferation by inactivating the IGF-1R-PI3 K/Akt pathway and decreasing the Bcl-2/Bax mRNA and protein expressions. Our findings help elucidate the mechanisms by which genistein may contribute to the prevention of breast cancer carcinogenesis.

An effective and simple procedure to isolate abundant quantities of biologically active chemopreventive Lunasin Protease Inhibitor Concentrate (LPIC) from soybean

Lunasin is a 5-kDa soybean bioactive peptide with demonstrated anti-cancer and anti-inflammatory properties. Recently, purification methods have been developed to obtain gram quantities of lunasin. However, these methods are cumbersome, time consuming and cost-prohibitive. To overcome these constrains we have developed a novel method which involves extraction of soybean flour with 30% ethanol followed by preferential precipitation of lunasin and protease inhibitors by calcium. The calcium precipitated protein fraction, which we termed as Lunasin Protease Inhibitor Concentrate (LPIC), contains three abundant proteins with molecular weights of 21, 14 and 5 kDa. This simple procedure yields 3.2g of LPIC from 100g of soybean flour and the entire isolation procedure can be completed in less than 2h. Treatment of THP-1 human monocyte cell lines with LPIC resulted in suppression of lipopolysaccharide-stimulated cytokine expression, demonstrating that the LPIC isolated by our simple procedure is biologically active.

Potential therapeutic mechanism of genistein in breast cancer involves inhibition of cell cycle regulation

Genistein can prevent tumorigenesis and reduce the incidence of diseases that are dependent upon estrogen. Previous research, however, has shown that genistein can also increase the risk of breast cancer. Thus, the aim of the present study was to investigate the mechanism underlying the effect of genistein in breast cancer and to determine whether genistein produces a therapeutic effect or promotes the development of breast cancer. Gene microarray data obtained from three samples treated with alcohol (control group), three samples treated with 3 μmol/l genistein and three samples treated with 10 μmol/l genistein for 48 h, were downloaded from the Gene Expression Omnibus database. Analysis of the differentially expressed genes (DEGs) and functional enrichment in the two genistein groups was performed. The interaction networks of the DEGs were constructed and the overlapping network was extracted. Finally, the functions and pathways of the DEGs in the overlapping network were enriched. In total, 224 DEGs coexisted in the two genistein groups, and the most significant function of these was the cell cycle. The number and the fold change of expression values of the DEGs in the 10 μmol/l genistein group were significantly higher compared with that of the 3 μmol/l genistein group. The most significant function and pathway of the DEGs in the overlapping network was the cell cycle involving several genes, including GLIPR1, CDC20, BUB1, MCM2 and CCNB1. Thus, genistein stimulation resulted in gene expression changes in breast cancer cell lines and discrepancies increased with higher doses of genistein. The DEGs were most significantly associated with cell cycle regulation.

The effects of soy supplementation on gene expression in breast cancer: a randomized placebo-controlled study

BACKGROUND

There are conflicting reports on the impact of soy on breast carcinogenesis. This study examines the effects of soy supplementation on breast cancer-related genes and pathways.

METHODS

Women (n = 140) with early-stage breast cancer were randomly assigned to soy protein supplementation (n = 70) or placebo (n = 70) for 7 to 30 days, from diagnosis until surgery. Adherence was determined by plasma isoflavones: genistein and daidzein. Gene expression changes were evaluated by NanoString in pre- and posttreatment tumor tissue. Genome-wide expression analysis was performed on posttreatment tissue. Proliferation (Ki67) and apoptosis (Cas3) were assessed by immunohistochemistry.

RESULTS

Plasma isoflavones rose in the soy group (two-sided Wilcoxon rank-sum test, P < .001) and did not change in the placebo group. In paired analysis of pre- and posttreatment samples, 21 genes (out of 202) showed altered expression (two-sided Student's t-test, P < .05). Several genes including FANCC and UGT2A1 revealed different magnitude and direction of expression changes between the two groups (two-sided Student's t-test, P < .05). A high-genistein signature consisting of 126 differentially expressed genes was identified from microarray analysis of tumors. This signature was characterized by overexpression (>2-fold) of cell cycle transcripts, including those that promote cell proliferation, such as FGFR2, E2F5, BUB1, CCNB2, MYBL2, CDK1, and CDC20 (P < .01). Soy intake did not result in statistically significant changes in Ki67 or Cas3.

CONCLUSIONS

Gene expression associated with soy intake and high plasma genistein defines a signature characterized by overexpression of FGFR2 and genes that drive cell cycle and proliferation pathways. These findings raise the concerns that in a subset of women soy could adversely affect gene expression in breast cancer.

Review article: health benefits of some physiologically active ingredients and their suitability as yoghurt fortifiers

The article is concerned with health benefits of two main physiologically active ingredients namely, Isoflavones and γ-Aminobutyric acid, with emphasis on their fitness for fortification of yoghurt to be consumed as a functional food. Isoflavones (ISO) are part of the diphenol compounds, called "phytoestrogens," which are structurally and functionally similar to estradiol, the human estrogen, but much less potent. Because of this similarity, ISO were suggested to have preventive effects for many kinds of hormone-dependent diseases. In nature, ISO usually occur as glycosides and, once deconjugated by the intestinal microflora, the ISO can be absorbed into the blood. At present, it seems convincing their possible protective actions against various cancers, osteoporosis and menopausal symptoms and high levels of blood cholesterol as well as the epidemiological evidence. Γ-Aminobutyric acid (GABA), it is an amino acid that has long been reported to lower blood pressure by intravenous administration in experimental animals and in human subjects. GABA is present in many vegetables and fruits but not in dairy products. GABA was reported to lower blood pressure in people with mild hypertension. It was suggested that low-dose oral GABA has a hypotensive effect in spontaneously hypertensive. Yoghurt beyond its ability to be probiotic food via its culturing with the gut strains, it could further carry more healthy benefits when it was fortified with physiological active ingredients, especially GABA versus ISO preferring, whether, bacteriologically or biochemically, a fortification level of 50 mg ISO/kg or 200 mg GABA/kg.

Combination of low dose of genistein and daidzein has synergistic preventive effects on isogenic human prostate cancer cells when compared with individual soy isoflavone

The reduced incidence of prostate cancer (PCa) in Asia countries has been attributed to high soy diets, and major soy isoflavones, in particular daidzein and genistein, are thought to be the source of the beneficial and anti-cancer effects of soy foods. However, attention has been drawn to the safety of using high levels of soy isoflavones in humans, which is especially the concern for consumers taking regular soy isoflavone dietary supplements. The main objective of this study is thus to identify a soy isoflavone combination with lower levels of daidzein and genistein to be a more efficacious and safer chemo-preventive agent for PCa. The anticancer effects of daidzein and genistein, and their combinations on early-stage androgen-dependent PCa cells (LNCaP) and bone metastatic LNCaP-derivative PCa cells (C4-2B) were compared. Cells were treated with varying concentrations of daidzein, genistein (25-200 μM) or their combinations (25 or 50 μM) and cell proliferation, apoptosis, cell cycles and cellular uptakes of the isoflavones were measured after 48 h. Daidzein and genistein showed a synergistic effect on inhibiting cell proliferation and inducing apoptosis of both PCa cells. Twenty-five μM daidzein/50 μM genistein and 50 μM daidzein/50 μM genistein significantly increased the apoptotic effects on C4-2B cells although they did not show any effect when used individually. Except 50 μM daidzein/50 μM genistein, all other combinations had no impacts on cell cycles. For treatment with soy isoflavone combination, genistein was always better taken up than daidzein by both LNCaP and C4-2B cells.

Post-diagnosis soy food intake and breast cancer survival: a meta-analysis of cohort studies

BACKGROUND AND OBJECTIVES

Data on associations between soy food intake after cancer diagnosis with breast cancer survival are conflicting, so we conducted this meta-analysis for more accurate evaluation.

METHODS

Comprehensive searches were conducted to find cohort studies of the relationship between soy food intake after cancer diagnosis and breast cancer survival. Data were analyzed with comprehensive meta-analysis software.

RESULTS

Five cohort studies (11,206 patients) were included. Pooling all comparisons, soy food intake after diagnosis was associated with reduced mortality (HR 0.85, 95%CI 0.77 0.93) and recurrence (HR 0.79, 95%CI 0.72 0.87). Pooling the comparisons of highest vs. lowest dose, soy food intake after diagnosis was again associated with reduced mortality (HR 0.84, 95%CI 0.71 0.99) and recurrence (HR 0.74, 95%CI 0.64 0.85). Subgroup analysis of ER status showed that soy food intake was associated with reduced mortality in both ER negative (highest vs. lowest: HR 0.75, 95%CI 0.64 0.88) and ER positive patients (highest vs. lowest: HR 0.72, 95%CI 0.61 0.84), and both premenopausal (highest vs. lowest: HR 0.78, 95%CI 0.69 0.88) and postmenopausal patients (highest vs. lowest: HR 0.81, 95%CI 0.73 0.91). In additioin, soy food intake was associated with reduced recurrence in ER negative (highest vs. lowest: HR 0.64, 95%CI 0.44 0.94) and ER+/PR+ (highest vs. lowest: HR 0.65, 95%CI 0.49 0.86), and postmenopausal patients (highest vs. lowest: HR 0.67, 95%CI 0.56 0.80).

CONCLUSION

Our meta- analysis showed that soy food intake might be associated with better survival, especially for ER negative, ER+/ PR+, and postmenopausal patients.

Cytology in nipple aspirate fluid during a randomized soy food intervention among premenopausal women

Because soy food consumption may influence breast tissue activity, we examined its effect on the presence of epithelial cells in nipple aspirate fluid (NAF). In a randomized, crossover design, 82 premenopausal women completed a high-soy and a low-soy diet for 6 mo each, separated by a 1-mo washout period. They provided NAF samples at baseline, 6 mo, and 13 mo during the midluteal phase of the menstrual cycle. Papanicolaou-stained cytology slides (for 33 women at baseline, 24 at low-soy, and 36 at high-soy) were evaluated in women with sufficient NAF. Mixed models evaluated the effect of the high-soy diet on epithelial cytology as compared to baseline and the low-soy diet. At the end of the high-soy diet, cytological subclass had decreased in 8 (24%) and increased in 3 (9%) women as compared to baseline, whereas the respective values were 3 (14%) and 6 (29%) for the low-soy diet samples (P = 0.32). Only the change in subclass indicated a trend in lower cytological class (P = 0.06). Contrary to an earlier report, the number of NAF samples with hyperplastic epithelial cells did not increase after a soy intervention in amounts consumed by Asians.

Anti-breast cancer potential of daidzein in rodents

AIMS

This study was carried out to explore anti-breast cancer potential of isoflavone daidzein or its related compounds using appropriate animal models and their anti-tumor mechanism.

MAIN METHODS

Daidzein or its major metabolite equol at a dose molar equivalent to tamoxifen [1.0 mg(2.7 μmol)/kg or 10 mg (27 μmol)/kg/day] was treated orally to rats bearing 7,12-dimethylbenz(a)anthracene(DMBA)-induced mammary tumors or ovariectomized athymic nude mice implanted with human MCF-7 breast cancer xenograft and an estrogen pellet. The growth of tumors was monitored for several weeks after the treatment. The cell-cycle and apoptotic stages in mammary tumors collected from rats were analyzed by flow cytometry. Immunohistochemistry analysis was also used to determine the expression of caspase-3.

KEY FINDINGS

Oral treatment with daidzein or equol at a human equivalent dose suppressed the growth of both DMBA-induced mammary tumors and human MCF-7 breast cancer xenografts in rodents, the inhibitory activity being superior to that of genistein or tamoxifen. Strong apoptosis induced by daidzein or equol contributes to the anti-tumor potential.

SIGNIFICANCE

Daidzein and its metabolite equol showed the potential of inhibiting the growth of mammary tumors in rodents. Daidzein or equol could be used as a core structure to design new drugs for breast cancer therapy. Our results indicate that consumption of daidzein may protect against breast cancer.

Nutrition and physical activity guidelines for cancer survivors

Cancer survivors are often highly motivated to seek information about food choices, physical activity, and dietary supplements to improve their treatment outcomes, quality of life, and overall survival. To address these concerns, the American Cancer Society (ACS) convened a group of experts in nutrition, physical activity, and cancer survivorship to evaluate the scientific evidence and best clinical practices related to optimal nutrition and physical activity after the diagnosis of cancer. This report summarizes their findings and is intended to present health care providers with the best possible information with which to help cancer survivors and their families make informed choices related to nutrition and physical activity. The report discusses nutrition and physical activity guidelines during the continuum of cancer care, briefly highlighting important issues during cancer treatment and for patients with advanced cancer, but focusing largely on the needs of the population of individuals who are disease free or who have stable disease following their recovery from treatment. It also discusses select nutrition and physical activity issues such as body weight, food choices, food safety, and dietary supplements; issues related to selected cancer sites; and common questions about diet, physical activity, and cancer survivorship.

Soy food intake after diagnosis of breast cancer and survival: an in-depth analysis of combined evidence from cohort studies of US and Chinese women

BACKGROUND

Soy isoflavones have antiestrogenic and anticancer properties but also possess estrogen-like properties, which has raised concern about soy food consumption among breast cancer survivors.

OBJECTIVE

We prospectively evaluated the association between postdiagnosis soy food consumption and breast cancer outcomes among US and Chinese women by using data from the After Breast Cancer Pooling Project.

DESIGN

The analysis included 9514 breast cancer survivors with a diagnosis of invasive breast cancer between 1991 and 2006 from 2 US cohorts and 1 Chinese cohort. Soy isoflavone intake (mg/d) was measured with validated food-frequency questionnaires. HRs and 95% CIs were estimated by using delayed-entry Cox regression models, adjusted for sociodemographic, clinical, and lifestyle factors.

RESULTS

After a mean follow-up of 7.4 y, we identified 1171 total deaths (881 from breast cancer) and 1348 recurrences. Despite large differences in soy isoflavone intake by country, isoflavone consumption was inversely associated with recurrence among both US and Chinese women, regardless of whether data were analyzed separately by country or combined. No heterogeneity was observed. In the pooled analysis, consumption of ≥10 mg isoflavones/d was associated with a nonsignificant reduced risk of all-cause (HR: 0.87; 95% CI: 0.70, 1.10) and breast cancer-specific (HR: 0.83; 95% CI: 0.64, 1.07) mortality and a statistically significant reduced risk of recurrence (HR: 0.75; 95% CI: 0.61, 0.92).

CONCLUSION

In this large study of combined data on US and Chinese women, postdiagnosis soy food consumption of ≥10 mg isoflavones/d was associated with a nonsignificant reduced risk of breast cancer-specific mortality and a statistically significant reduced risk of recurrence.

Alternative and complementary therapies for the menopause

Despite a re-evaluation of risks in recent years, hormone replacement therapy is still surrounded by controversy. Almost 30% of women in a recent survey sought a natural approach to combat climacteric symptoms. Nevertheless, a large proportion of patients felt that they wanted a good safety profile and strong evidence base for treatment. This article seeks to review the evidence supporting non-hormonal approaches to treatment. There is only conflicting evidence at best to support alpha-2 agonists, e.g. clonidine and limited evidence for dihydroepiandrosterone and natural progesterones. There is limited randomized controlled trial data for gabapentin, selective norepinephrine re-uptake inhibitors (SNRIs) and selective serotonin re-uptake inhibitors (SSRIs), many of these studies being related to breast cancer patients. Of the herbal medicinal products, the largest evidence base rests with phytoestrogens. A Cochrane Database review looking at all types of phytoestrogens, e.g. red clover extracts, dietary soya and soya extracts concluded that there was no evidence to support improvement in climacteric symptoms and the meta-analysis of a 178 studies on soy products was inconsistent. Nevertheless, other studies disagree. Mammographic density is not affected by soy or phytoestrogen products and recent in vitro work shows only a weakly proliferative effect of soy isoflavone on breast cancer cells and evidence that soy isoflavone blocks the proliferative effect of estradiol on these cells. There are no studies looking at clinical outcome measures for cardiovascular disease but a number of studies looking at biochemical markers including arterial wall stiffness and apolipo protein B. Recent studies have also looked at the effects of red clover isoflavone on mood and depression, using specific depression rating scales. Finally, it is important to note that herbal medicinal products should not be used without caution. Some may produce quite marked side-effects in high doses and others can interact with pre-existing medication. A strategy for which patients are suitable for herbal medicinal products is reviewed.

Urinary estrogen metabolites in two soy trials with premenopausal women

Background

Soy consumption may protect against breast cancer through modification of estrogen metabolism.

Objective

We examined the effect of soy foods on urinary estrogens and the 2-hydroxy (OH)/16α-OH estrone (E₁) ratio in 2 dietary interventions with premenopausal women.

Methods

BEAN1 was a 2-year randomized trial and BEAN2 a 13-month randomized crossover study. In both interventions, study participants consumed a high-soy diet with 2 soy food servings/day and a low-soy diet with <3 servings of soy/week. Urine samples were collected at baseline and at the end of the diet periods, analyzed for 9 estrogen metabolites by liquid chromatography mass spectrometry, and adjusted for creatinine levels. For BEAN1, 2 samples for 188 participants and for BEAN2, 3 samples for 79 women were analyzed. We applied mixed-effects regression models with log-transformed values of estrogen metabolites and soy intake as the exposure variable.

Results

In BEAN1, no effect of the high-soy diet on individual estrogen metabolites or hydroxylation pathways was observed. The median 2-OH/16α-OH E₁ ratio decreased non-significantly in the intervention group from 6.2 to 5.2 as compared to 6.8 and 7.2 in the control group (p=0.63). In BEAN2, only 4-OHE₁ was significantly lower after the high-soy diet. Interaction terms of the high-soy diet with equol producer status, ethnicity, and weight status revealed no significant effect modification.

Conclusions

Contrary to our hypothesis and some previous reports, the results from 2 well controlled dietary interventions do not support an effect of a high-soy diet on a panel of urinary estrogen metabolites and the 2-OH/16α-OHE₁ ratio.

Conventional (MG-BR46 Conquista) and transgenic (BRS Valiosa RR) soybeans have no mutagenic effects and may protect against induced-DNA damage in vivo

In the present study, we evaluated the pesticide and metal concentrations as well as the antimutagenic and mutagenic properties of commercial soybeans (Glycine max). Male Swiss mice were fed diets containing 1%, 10%, or 20% (w/w) transgenic soybeans (BRS Valiosa RR) or parental isogenic conventional soybeans (MG-BR46 Conquista). Cyclophosphamide (50 mg kg⁻¹ b.w.) was added in a single dose 24 h before euthanasia as an induction agent. There was no difference in the composition (ash, total fat, protein, moisture, and carbohydrates) of the diets containing the same soybean concentration. The results show that the commercially available Brazilian soybeans tested are free of organochlorine, organophosphate, and carbamate pesticides and contain acceptable heavy metal concentrations. Both cyclophosphamide and soybean treatments were not sufficient to cause detectable oxidative damage on liver by the levels of malondialdehyde and protein carbonyl. The transgenic soybeans are also nonmutagenic and have protective effects against DNA damage similar to those of conventional soybeans but to a lesser percentage (64%-101% for conventional and 23%-33% for transgenic diets).

Epigenetics and breast cancers

Several of the active compounds in foods, poisons, drugs, and industrial chemicals may, by epigenetic mechanisms, increase or decrease the risk of breast cancers. Enzymes that are involved in DNA methylation and histone modifications have been shown to be altered in several types of breast and other cancers resulting in abnormal patterns of methylation and/or acetylation. Hypermethylation at the CpG islands found in estrogen response element (ERE) promoters occurs in conjunction with ligand-bonded alpha subunit estrogen receptor (Erα) dimers wherein the ligand ERα dimer complex acts as a transcription factor and binds to the ERE promoter. Ligands could be 17-β-estradiol (E2), phytoestrogens, heterocyclic amines, and many other identified food additives and heavy metals. The dimer recruits DNA methyltransferases which catalyze the transfer of methyl groups from S-adenosyl-L-methionine (SAM) to 5'-cytosine on CpG islands. Other enzymes are recruited to the region by ligand-ERα dimers which activate DNA demethylases to act simultaneously to increase gene expression of protooncogenes and growth-promoting genes. Ligand-ERα dimers also recruit histone acetyltransferase to the ERE promoter region. Histone demethylases such as JMJD2B and histone methyltransferases are enzymes which demethylate lysine residues on histones H3 and/or H4. This makes the chromatin accessible for transcription factors and enzymes.

Dietary, endocrine, and metabolic factors in the development of colorectal cancer

INTRODUCTION

Colorectal cancer is the third cause of death in industrialized countries. Genetic susceptibility and diet are determinant of cancer risk and tumor behavior. Variation in cancer incidence among and within populations with similar dietary patterns suggests that an individual response may reflect interactions with genetic factors, which may modify gene, protein, and metabolite expression patterns. Nutrigenomics, defined as the interaction between nutrition and an individual genome, will likely provide important clues about responders and non-responders to nutritional intervention.

DISCUSSION

Epidemiological and experimental studies suggest a protective role of some normal components of daily diet (fish oil, milk, and vegetables), estrogens, and phytoestrogens in colorectal cancer. The effect of estrogen seems to be mediated by their binding to estrogen receptor beta (ER-β), one of the two estrogen receptors with high affinity for these hormones. Very recently, the demonstration of an involvement of ER-β in the development of adenomatous polyps of the colon has also been documented, suggesting the use of selective ER-β agonists in primary colorectal cancer prevention. Phytoestrogens are plant-derived compounds that structurally and functionally act as estrogen agonists in mammals. They are characterized by a higher binding affinity to ER-β as compared to estrogen receptor alpha (ER-α), the other estrogen receptor subtype. These biological characteristics explain why the administration of phytoestrogens does not produce the classical side effects associated to estrogen administration (cerebro- and cardiovascular accidents, higher incidence of endometrial and breast cancer) and makes these substances potential candidates for colorectal cancer prevention.