Soy food consumption and breast cancer

Association between dietary factors and breast cancer risk: a matched case-control study in Vietnam

BACKGROUND

The role of diet in breast cancer prevention is controversial and limited in low-middle-income countries (LMICs). This study aimed to investigate the association between different dietary factors and breast cancer risk in Vietnamese women.

METHODS

Three hundred seventy newly histologically confirmed breast cancer cases and 370 controls matched by 5-year age from September 2019 to March 2020 in Ho Chi Minh City were recorded dietary intake using a validated food frequency questionnaire. Odds ratios (OR) and 95% confidence intervals (95% CI) were evaluated using conditional logistic regression and adjusted with potential confounders.

RESULTS

Compared to the lowest quartile of intake, we found that the highest intake of vegetables, fruit, soybean products, coffee, and egg significantly decreased breast cancer risk, including dark green vegetables (OR 0.46, 95% CI 0.27-0.78, ptrend=0.022), legumes (OR 0.19, 95% CI 0.08-0.44, ptrend <0.001), starchy vegetables (OR 0.37, 95% CI 0.21-0.66, ptrend=0.003), other vegetables (OR 0.46, 95% CI 0.28-0.77, ptrend=0.106), fruits (OR 0.44, 95% CI 0.26-0.74, ptrend <0.001), soybean product (OR 0.45, 95% CI 0.24-0.86, ptrend=0.311), coffee (OR 0.47, 95% CI 0.23-0.95, ptrend 0.004), and egg (OR 0.4, 95% CI 0.23-0.71, ptrend=0.002).

CONCLUSION

Greater consumption of vegetables, fruit, soybean products, coffee, and eggs is associated with a lower risk of breast cancer. This study provides evidence of breast cancer prevention by increasing the intake of these dietary groups, especially in LMICs.

Pre-diagnosis and early post-diagnosis dietary soy isoflavone intake and survival outcomes: A prospective cohort study of early stage breast cancer survivors

BACKGROUND

There is concern that the estrogen-like effects of soy isoflavones may stimulate mammary tumor growth and interfere with the efficacy of breast cancer treatment. This study aimed to examine prospectively the associations of dietary soy isoflavone intake with all-cause mortality and breast cancer (BC) specific mortality and recurrence among BC survivors.

DESIGN

The study included 1460 Chinese women with early-stage incident BC. Pre-diagnosis and early post-diagnosis soy food intakes were assessed at study entry, and at 18-month follow-up using validated soy food frequency questionnaire. Associations of soy isoflavone intake with prognostic outcomes within 48 months were examined using multivariable adjusted Cox proportional hazards models.

RESULTS

We observed increasing pre-diagnosis and early post-diagnosis soy isoflavone intakes up to the third quartile (Q3) were associated with reductions for adverse prognostic outcomes. Relative to the lowest quartile (Q1), the hazard ratios (HRs) for all-cause mortality for pre-diagnosis and post-diagnosis Q3 intake were respectively 0.34 (95% CI, 0.16-0.74), and 0.44 (95% CI, 0.22-0.89). A similar risk reduction was observed for pre- and post-diagnosis intakes and BC-specific mortality when comparing Q3 versus Q1 with the respective HRs 0.36 (95% CI, 0.16-0.82), and 0.49 (95% CI, 0.23-1.01). Subgroup analyses showed more favourable prognostic outcomes in association with moderate soy intake among premenopausal women, those with triple negative cancer and recipients of tamoxifen treatment.

CONCLUSION

Moderate soy isoflavone intake was associated with favourable prognostic outcomes in Chinese early stage BC survivors.

Dietary Intake of Essential Elements (Na, K, Mg, Ca, Mn, Zn, Fe, Cu, Mo, Co) from Tofu Consumption

Tofu is one of the most consumed soybean products. Currently, tofu is consumed in vegan and vegetarian diets to avoid meat. However, it is necessary to determine the content of essential elements to assess the dietary intake. Essential elements (Na, K, Mg, Ca, Mn, Zn, Fe, Cu, Mo, Co) were determined in 130 samples of tofu by ICP-OES (inductively coupled plasma optical emission spectroscopy). The highest element content was found in flavoured tofu; the most notable were Na (2519 mg/kg wet weight) and Fe (19.5 mg/kg ww). Consumption of 200 g/day of flavoured tofu by adults would mean a high contribution of Cu (46.9% women, 38.1% men), Fe (55.7% women, 65.0% men) and Na (25.2% adults) to its AI (adequate intakes) sets by the EFSA (European Food Safety Authority). Natural tofu would mean a remarkably Mn contribution (50% adults) to the AI. Tofu could be an important source of essential elements such as Mg, Mn, Na, Cu and Fe.

Phytochemicals in Legumes: A Qualitative Reviewed Analysis

Legumes are an excellent source of nutrients and phytochemicals. They have been recognized for their contributions to health, sustainability, and the economy. Although legumes comprise several species and varieties, little is known about the differences in their phytochemical composition and the magnitude of these. Therefore, the aim of this review is to describe and compare the qualitative profile of phytochemicals contained in legumes and identified through LC-MS and GC-MS methods. Among the 478 phytochemicals reported in 52 varieties of legumes, phenolic compounds were by far the most frequently described (n = 405, 85%). Metabolomics data analysis tools were used to visualize the qualitative differences, showing beans to be the most widely analyzed legumes and those with the highest number of discriminant phytochemicals (n = 180, 38%). A Venn diagram showed that lentils, beans, soybeans, and chickpeas shared only 7% of their compounds. This work highlighted the huge chemical diversity among legumes and identified the need for further research in this field and the use of metabolomics as a promising tool to achieve it.

Breast Cancer Primary Prevention and Diet: An Umbrella Review

Introduction: Many studies have been published, but none have pooled the useful evidence available in the literature to produce guidelines and health policies promoting healthy eating styles to prevent breast cancer (BC). The present study aimed to summarize the evidence produced to date, taking a judicious, critical approach to the quality of the studies analyzed. Methods: An umbrella review method was adopted, which is a systematic review of second-level studies, meta-analyses and literature reviews. Results: In all, 48 studies were considered: 32 meta-analyses, 4 pooled analyses, 5 systematic reviews, and 7 qualitative reviews. A higher intake of total meat, or red or processed meats, or foods with a high glycemic index, or eggs would seem to be associated with a higher risk of BC. Some foods, such as vegetables, would seem instead to have an inverse association with BC risk. One meta-analysis revealed an inverse association between citrus fruit and mushroom consumption and BC. Some nutrients, such as calcium, folate, vitamin D, lignans and carotenoids, also seem to be inversely associated with BC risk. The evidence is still conflicting as concerns exposure to other dietary elements (e.g., polyunsaturated fatty acids, dairy foods). Conclusion: Nutrition is one of the most modifiable aspects of people's lifestyles and dietary choices can affect health and the risk of cancer. Overall, adhering to a healthy eating style may be associated with a significant reduction in the risk of BC.

Impact of soy consumption on human health: integrative review

Abstract Soy consumption is a millenary habit of populations of the eastern world and has recently increased in the western world. The risks and benefits of this practice have been extensively studied, with a current fundamental need of integration of available information. The aim of this study was to carry out an integrative review on this topic, in order to consolidate the available information. Based on the main question: “What is the impact of soy consumption on human health?”, were reviewed publications classified as original articles and reviews published from 1998 to 2020 in the databases Scopus, PubMed, SciELO, Web of Science, and Cochrane Library. A total of 97 studies were selected. In the present review were described the general impact of soy on human health and its protein quality, the effects of early exposure using soy formulas, and the effects of soy consumption on breast cancer, endometrial and ovarian cancer, prostate cancer, gastrointestinal cancer, cardiovascular disease, glucose metabolism and type 2 diabetes, obesity, reproductive health, menopause, female and male osteoporosis, microbiota, immunity and immunomodulation, thyroid function, attention-deficit hyperactivity disorder, and renal function.

Secular Trends in Energy and Macronutrient Intakes and Distribution among Adult Females (1991-2015): Results from the China Health and Nutrition Survey

With rapid nutrition transition in China, dietary intake and nutritional status of women has gained more and more attention in the past decades. This study aimed to investigate temporal trends of total energy and macronutrient intakes among Chinese adult females. The longitudinal data are from the Chinese Health and Nutrition Survey (CHNS, 1991-2015). Information on the intake of energy and macronutrient was obtained from consecutive three-day dietary recall techniques and compared with the Chinese Dietary Reference Intakes (DRI). Mixed-effect models were performed to evaluate temporal trends of total energy and macronutrient intake. From 1991 to 2015, a significant reduction in daily energy, protein and carbohydrate intakes was seen among all adult females (p < 0.001). Daily fat intake, the proportion of energy from fat, the proportion of females consuming more than 30% of energy from fat and less than 50% of energy from carbohydrate were observed significant increment in the present study (p < 0.001). In 2015, the proportion met the DRI for energy and protein intakes were 47.0% and 48.0%, respectively; the proportion with lower carbohydrate and higher fat intakes compare with the DRI were 45.5% and 66.9%, respectively. Further nutritional education and policy interventions still needed to improve nutrition status for Chinese females.

Comprehensive evaluation of the role of soy and isoflavone supplementation in humans and animals over the past two decades

Soy and soy-based foods are considered healthy, particularly in many Asia-Pacific countries, where soy products have long been consumed. Soy and soy-related products have been found to help prevent the occurrence of cardiovascular diseases and certain types of cancer, such as breast and prostate cancer. These products can also have antioxidative effects that alleviate hot flashes during menopause and bone loss. These biological and therapeutic functions are primarily due to the isoflavones derived from soy, whose structure is similar to the structure of 17-β-oestradiol. Despite the many health benefits for humans and animals, the application of isoflavones remains controversial because of their anti-oestrogenic properties. We focused on general information regarding isoflavones, as well as their structure, function, and application. We summarized evidence showing that dietary or supplemental isoflavones exert protective effects on the health of humans and animals. Based on the literature, we conclude that soy foods and isoflavones may be effective and safe; however, more high-quality trials are needed to fully substantiate their potential use.

Estrogenic Potentials of Traditional Chinese Medicine

Estrogen, a steroid hormone, is associated with several human activities, including environmental, industrial, agricultural, pharmaceutical and medical fields. In this review paper, estrogenic activity associated with traditional Chinese medicines (TCMs) is discussed first by focusing on the assays needed to detect estrogenic activity (animal test, cell assay, ligand-binding assay, protein assay, reporter-gene assay, transcription assay and yeast two-hybrid assay), and then, their sources, the nature of activities (estrogenic or anti-estrogenic, or other types), and pathways/functions, along with the assay used to detect the activity, which is followed by a summary of effective chemicals found in or associated with TCM. Applications of estrogens in TCM are then discussed by a comprehensive search of the literature, which include basic study/pathway analysis, cell functions, diseases/symptoms and medicine/supplements. Discrepancies and conflicting cases about estrogenicity of TCM among assays or between TCM and their effective chemicals, are focused on to enlarge estrogenic potentials of TCM by referring to omic knowledge such as transcriptome, proteome, glycome, chemome, cellome, ligandome, interactome and effectome.

Phytochemical profiling of underexploited Fabaceae species: Insights on the ontogenic and phylogenetic effects over isoflavone levels

There is an increasing trend towards finding alternative sources of valued phytochemicals due to their diverse potentialities in food industry and pharmaceutical applications. Phenolic compounds, in particular, have been the focus of several profiling reports, but isoflavones characterization has been studied in fewer cases and in a very limited group of plant species. Despite their acknowledged bioactivity, there's actually a strict number of plants validated for their isoflavones contents. In a previous report, we have identified nine Leguminosae species (from genera Biserrula, Lotus, Ornithopus and Scorpiurus) as potential alternative sources of these phenolic compounds. However, the isoflavone profiles are highly modulated by the ontogenic stage. Therefore, the present study was conducted in the same Leguminosae species, but harvested at three sequential vegetative development stages: vegetative elongation, late bud and late flowering, with the main purpose of assessing the evolution of isoflavones content throughout the plant development. In general, the plant species from Biserrula and Lotus genera showed the highest potential as new natural sources of isoflavones, especially owing their high levels of biochanin A. Independently of the plant species, it was possible to identify the phenologic stages where each of the quantified isoflavones is maximized. These findings are useful to predict isoflavone yields according to harvesting time, validating the potential use of the studied plants in innovative food formulations.

Colloidal gold-based indirect competitive immunochromatographic assay for rapid detection of bioactive isoflavone glycosides daidzin and genistin in soy products

Daidzin (DZ) and genistin (GEN) are two major soy isoflavone glycosides isolated from soybeans. Soy products containing isoflavones have recently been widely accepted for commercial use. However, the Japanese Government has suggested that soy isoflavone intake should be limited because of their estrogenic effects due to their interactions with estrogen receptors. In this study, we established a one-step indirect competitive immunochromatographic assay (ICA) for rapid and sensitive detection of total isoflavone glycosides (DZ and GEN) using gold nanoparticles conjugated with a monoclonal antibody against DZ. This assay was able to be completed in 15min following the immersion of a test strip in an analyte solution. Furthermore, the limit of detection for the total amount of isoflavone glycosides was ∼125ngmL(-1). Considering that the major soy isoflavone glycosides found in soy products are DZ and GEN, this study demonstrates the potential use of ICA for the assessments of over consumption of isoflavones in soy supplements and foods, which would increase the safe dietary intake of soy products.

Resveratrol for breast cancer prevention and therapy: Preclinical evidence and molecular mechanisms

Globally, breast cancer is the most frequently diagnosed cancer among women. The major unresolved problems with metastatic breast cancer is recurrence after receiving objective response to chemotherapy, drug-induced side effects of first line chemotherapy and delayed response to second line of treatment. Unfortunately, very few options are available as third line treatment. It is clear that under such circumstances there is an urgent need for new and effective drugs. Phytochemicals are among the most promising chemopreventive treatment options for the management of cancer. Resveratrol (3,5,4'-trihydroxy-trans-stilbene), a non-flavonoid polyphenol present in several dietary sources, including grapes, berries, soy beans, pomegranate and peanuts, has been shown to possess a wide range of health benefits through its effect on a plethora of molecular targets.The present review encompasses the role of resveratrol and its natural/synthetic analogue in the light of their efficacy against tumor cell proliferation, metastasis, epigenetic alterations and for induction of apoptosis as well as sensitization toward chemotherapeutic drugs in various in vitro and in vivo models of breast cancer. The roles of resveratrol as a phytoestrogen, an aromatase inhibitor and in stem cell therapy as well as adjuvent treatment are also discussed. This review explores the full potential of resveratrol in breast cancer prevention and treatment with current limitations, challenges and future directions of research.

Mechanism of Breast Cancer Preventive Action of Pomegranate: Disruption of Estrogen Receptor and Wnt/β-Catenin Signaling Pathways

A pomegranate emulsion (PE), containing various bioactive phytochemicals, has recently been found to exert substantial chemopreventive effect against 7,12-dimethylbenz(a)anthracene (DMBA)-induced mammary tumorigenesis in rats via antiproliferative and proapoptotic actions. Nevertheless, the underlying mechanisms of action are not completely understood. The present study was designed to investigate the effects of PE treatment on intratumor expression of estrogen receptor (ER)-α, ER-β,β-catenin and cyclin D1 during DMBA rat mammary carcinogenesis. Mammary tumor sections were harvested from a chemopreventive study in which PE (0.2, 1.0 and 5.0 g/kg) exhibited inhibition of mammary tumorigenesis in a dose-response manner. The expressions of ER-α, ER-β, β-catenin and cyclin D1 were analyzed by immunohistochemical techniques. PE downregulated the expression of intratumor ER-α and ER-β and lowered ER-α:ER-β ratio. PE also decreased the expression, cytoplasmic accumulation, and nuclear translocation of β-catenin, an essential transcriptional cofactor for Wnt signaling. Moreover, PE suppressed the expression of cell growth regulatory protein cyclin D1, which is a downstream target for both ER and Wnt signaling. Our current results in conjunction with our previous findings indicate that concurrent disruption of ER and Wnt/β-catenin signaling pathways possibly contributes to antiproliferative and proapoptotic effects involved in PE-mediated chemoprevention of DMBA-inflicted rat mammary tumorigenesis.

Punica granatum and its therapeutic implications on breast carcinogenesis: A review

Punica granatum has a recorded history of pharmacological properties which can be attributed to its rich reservoir of phytochemicals. Investigations in recent years have established its tremendous potential as an antitumorogenic agent against various cancers including breast cancer, which is the second leading cause of cancer-related deaths in women. The plausible role of Punica as a therapeutic agent, as an adjuvant in chemotherapy, and its dietary implications as chemopreventive agent in breast cancer have been explored. Mechanistic studies have revealed that Punica extracts and its components, individually or in combination, can modulate and target key proteins and genes involved in breast cancer. Our earlier finding also demonstrated the role of methanolic extract of pomegranate pericarp in reducing proliferation in breast cancer by binding to estrogen receptor at the same time not affecting uterine weight unlike estradiol or tamoxifen. This review analyses other plausible mechanisms of Punica in preventing the progression of breast cancer and how it can possibly be a therapeutic agent by acting at various steps of carcinogenesis including proliferation, invasion, migration, metastasis, angiogenesis, and inflammation via various molecular mechanisms.

Simultaneous determination of soy isoflavone glycosides, daidzin and genistin by monoclonal antibody-based highly sensitive indirect competitive enzyme-linked immunosorbent assay

Soy isoflavones are known as major bioactive compounds in soybean (Glycine max), which is an indispensable food. Despite their utility, the consumption of isoflavones has recently been limited because they exhibit oestrogenic and topoisomerase II inhibitory effects. To assess their intake limitation, accurate, sensitive, and effective quantitative analyses are necessary. In this study, we produced the monoclonal antibody (MAb) against daidzin (DZ) and applied it to an indirect competitive enzyme-linked immunosorbent assay (icELISA) for the simultaneous determination of DZ and genistin (GEN), which are known as two major soy isoflavone glycosides in soy products. Using the DZ-MAb, we developed a sensitive icELISA method, where the limit of detection for DZ and GEN was 1.95ng/ml. Several validation analyses revealed that the icELISA is sufficiently accurate and sensitive to be used to assess the overconsumption of soy isoflavones, which would lead to the safe dietary intake of soy products.

High levels of dietary soy decrease mammary tumor latency and increase incidence in MTB-IGFIR transgenic mice

BACKGROUND

Epidemiologic data indicates that Asian diets, which are high in soy protein, reduce a women's risk of developing breast cancer. However, it has been difficult to dissociate the benefits of soy from other variables including environmental and lifestyle factors. Since prospective studies in humans would take decades to complete, rodent models provide a valuable research alternative.

METHODS

In this study, MTB-IGFIR transgenic mice, which develop mammary tumors resulting from overexpression of the type I insulin-like growth factor receptor (IGF-IR), were utilized. MTB-IGFIR mice were fed a soy-based or casein-based diet throughout all stages of development to reflect soy exposure in Asian cultures. Mammary tumors were initiated at 2 different developmental stages by commencing IGF-IR transgene expression either during puberty or in adult mice.

RESULTS

MTB-IGFIR mice fed a soy-based diet displayed increased tumor incidence and accelerated tumor onset compared to MTB-IGFIR mice fed a casein diet. Two markers of estrogen receptor signaling, Pgr and Areg, were elevated in mammary tissue from mice fed the soy diet compared to mice fed the casein diet suggesting that high levels of soy may promote mammary tumor development through acting as an estrogen receptor agonist. Mammary tumors from mice fed a soy diet more frequently expressed metaplastic markers such as cytokeratins 5 and 14 as well as p63 and displayed reduced lung metastases compared to mammary tumors from mice fed a casein diet.

CONCLUSIONS

Diets consisting of very high levels of soy protein promote mammary tumor development and decrease tumor latency possibly through activating estrogen receptor signaling. Additional studies are required to determine whether a more moderate amount of dietary soy can inhibit oncogene-induced mammary tumorigenesis.