Soy isoflavones interact with calcium and contribute to blood pressure homeostasis in women: a randomized, double-blind, placebo controlled trial

Dietary isoflavone intake is inversely associated with remnant cholesterol in US adults: A cross-sectional study

BACKGROUND

Several studies have shown that dietary isoflavones are negatively correlated with total cholesterol and low-density lipoprotein cholesterol. However, few studies have investigated the link between dietary isoflavones and remnant cholesterol (RC).

OBJECTIVES

We used the National Health and Nutrition Examination Survey (NHANES) database to explore the association between dietary isoflavone intake and RC.

METHODS

A cross-sectional study was conducted with 4731 participants aged ≥ 20 years from the 2007-2008, 2009-2010, and 2017-2018 NHANES databases. We adopted univariate and multiple linear regression analysis and restricted cubic spline (RCS) to assess the relationship between dietary isoflavone intake and RC. Moreover, we conducted stratified and interaction analyses to ensure the stability of the results and identify specific populations.

RESULTS

The weighted multifactor linear regression model showed a negative correlation between dietary isoflavone intake and remnant cholesterol (Model 2, β = -0.049, 95% CI: (-0.096, -0.002), P = 0.040). The RCS analysis indicated that there was an L-shaped negative correlation between dietary isoflavone intake and RC (P-value for non-linearity was 0.0464). Stratified analyses showed the inverse relationship between dietary isoflavone intake and RC persisted in most subgroups and there was no interaction except for the recreational activity group.

CONCLUSIONS

Our study found a non-linear and negative association between dietary isoflavone intake and RC in US adults, so we hypothesized that consuming an isoflavone-rich diet may help reduce blood RC and further reduce the risk of cardiovascular disease.

Soy isoflavones decrease fibroglandular breast tissue measured by magnetic resonance imaging in premenopausal women: A 2-year randomized double-blind placebo controlled clinical trial

BACKGROUND & AIMS

Populations consuming soy have reduced risk for breast cancer, but the mechanisms are unclear. We tested the hypothesis that soy isoflavones, which have ovarian hormone-like effects, can reduce fibroglandular breast tissue (FGBT, 'breast density'), a strong risk marker for breast cancer.

METHODS

Premenopausal women (age 30-42 years) were randomized to consume isoflavones (136.6 mg as aglycone equivalents, n = 99) or placebo (n = 98) for 5 days per week up to 2 years, and changes in breast composition measured by magnetic resonance imaging at baseline and yearly intervals were compared after square root transformation using linear mixed effects regression models.

RESULTS

By intention-to-treat analyses (n = 194), regression coefficients (β estimates) of the interaction of time and isoflavone treatment were -0.238 (P = 0.06) and -0.258 (P < 0.05) before and after BMI adjustment, respectively for FGBT, 0.620 (P < 0.05) and 0.248 (P = 0.160), respectively for fatty breast tissue (FBT), and -0.155 (P < 0.05) and -0.107 (P < 0.05), respectively for FGBT as percent of total breast (FGBT%). β Estimates for interaction of treatment with serum calcium were -2.705 for FBT, and 0.588 for FGBT% (P < 0.05, before but not after BMI adjustment). BMI (not transformed) was related to the interaction of treatment with time (β = 0.298) or with calcium (β = -1.248) (P < 0.05). Urinary excretion of isoflavones in adherent subjects (n = 135) significantly predicted these changes in breast composition. Based on the modeling results, after an average of 1.2, 2.2 and 3.3 years of supplementation, a mean decrease of FGBT by 5.3, 12.1, and 19.3 cc, respectively, and a mean decrease of FGBT% by 1.37, 2.43, and 3.50%, respectively, were estimated for isoflavone exposure compared to placebo treatment. Subjects with maximum isoflavone excretion were estimated to have 38 cc less FGBT (or ∼3.13% less FGBT%) than subjects without isoflavone excretion. Decrease in FGBT and FGBT% was more precise with daidzein than genistein.

CONCLUSIONS

Soy isoflavones can induce a time- and concentration-dependent decrease in FGBT, a biomarker for breast cancer risk, in premenopausal women, and moderate effects of calcium on BMI and breast fat, suggesting a beneficial effect of soy consumption.

TRIAL REGISTRATION

www.

CLINICALTRIALS

gov identifier: NCT00204490.

TRIAL REGISTRATION

www.

CLINICALTRIALS

gov identifier: NCT00204490.

Targeting Breast Cancer Stem Cells Using Naturally Occurring Phytoestrogens

Breast cancer therapies have made significant strides in improving survival for patients over the past decades. However, recurrence and drug resistance continue to challenge long-term recurrence-free and overall survival rates. Mounting evidence supports the cancer stem cell model in which the existence of a small population of breast cancer stem cells (BCSCs) within the tumor enables these cells to evade conventional therapies and repopulate the tumor, giving rise to more aggressive, recurrent tumors. Thus, successful breast cancer therapy would need to target these BCSCs, as well the tumor bulk cells. Since the Women’s Health Initiative study reported an increased risk of breast cancer with the use of conventional hormone replacement therapy in postmenopausal women, many have turned their attention to phytoestrogens as a natural alternative. Phytoestrogens are plant compounds that share structural similarities with human estrogens and can bind to the estrogen receptors to alter the endocrine responses. Recent studies have found that phytoestrogens can also target BCSCs and have the potential to complement conventional therapy eradicating BCSCs. This review summarized the latest findings of different phytoestrogens and their effect on BCSCs, along with their mechanisms of action, including selective estrogen receptor binding and inhibition of molecular pathways used by BCSCs. The latest results of phytoestrogens in clinical trials are also discussed to further evaluate the use of phytoestrogen in the treatment and prevention of breast cancer.

The multimodal action of genistein in Alzheimer's and other age-related diseases

Genistein is a phytoestrogen that, due to its structural similarity with estrogen, can both mimic and antagonize estrogen effects. Early analysis proved that at high concentrations, genistein inhibits breast cancer cell proliferation, thereby suggesting an anticancer activity. Since then, many discoveries have identified the genistein mechanism of action, including cell cycle arrest, apoptosis induction, as well as angiogenesis, and metastasis inhibition. In this review, we aim to discuss the multimodal action of genistein as an antioxidant, anti-inflammatory, anti-amyloid β, and autophagy promoter, which could be responsible for the genistein beneficial effect on Alzheimer's. Furthermore, we pinpoint the main signal transduction pathways that are known to be modulated by genistein. Genistein has thus several beneficial effects in several diseases, many of them associated with age, such as the above mentioned Alzheimer disease. Indeed, the beneficial effects of genistein for health promotion depend on each multimodality. In the context of geroscience, genistein has promising beneficial effects due to its multimodal action to treat age associated-diseases.

Dietary isoflavones intake is inversely associated with non-alcoholic fatty liver disease, hyperlipidaemia and hypertension

This study investigated associations between total isoflavones and their categories (daidzein, genistein, glycitein) intake and the risks for metabolic disorders. We used the data of 6786 Chinese adults from the Nutrition Health Atlas Project. We performed multiple logistic regression and restricted cubic spline models assessing the risks for metabolic disorders (non-alcoholic fatty liver disease (NAFLD), hyperlipidaemia, hypertension, diabetes and overweight/obesity) in each category of isoflavones. Higher total isoflavones, daidzein and genistein intake were inversely associated with NAFLD (p < .05). Higher total isoflavones, daidzein, genistein and glycitein intake were also inversely associated with hyperlipidaemia (p < .01) and hypertension (p < .01). Dose-response analyses revealed that total isoflavones, daidzein, genistein and glycitein intakes were associated with the risks of metabolic disorders in a nonlinear trend. In conclusion, total isoflavones, daidzein and genistein intake were inversely associated with NAFLD, hyperlipidaemia and hypertension. Glycitein was inversely associated with hyperlipidaemia and hypertension.

Current Perspectives on the Beneficial Effects of Soybean Isoflavones and Their Metabolites for Humans

Soybeans are rich in proteins and lipids and have become a staple part of the human diet. Besides their nutritional excellence, they have also been shown to contain various functional components, including isoflavones, and have consequently received increasing attention as a functional food item. Isoflavones are structurally similar to 17-β-estradiol and bind to estrogen receptors (ERα and ERβ). The estrogenic activity of isoflavones ranges from a hundredth to a thousandth of that of estrogen itself. Isoflavones play a role in regulating the effects of estrogen in the human body, depending on the situation. Thus, when estrogen is insufficient, isoflavones perform the functions of estrogen, and when estrogen is excessive, isoflavones block the estrogen receptors to which estrogen binds, thus acting as an estrogen antagonist. In particular, estrogen antagonistic activity is important in the breast, endometrium, and prostate, and such antagonistic activity suppresses cancer occurrence. Genistein, an isoflavone, has cancer-suppressing effects on estrogen receptor-positive (ER+) cancers, including breast cancer. It suppresses the function of enzymes such as tyrosine protein kinase, mitogen-activated kinase, and DNA polymerase II, thus inhibiting cell proliferation and inducing apoptosis. Genistein is the most biologically active and potent isoflavone candidate for cancer prevention. Furthermore, among the various physiological functions of isoflavones, they are best known for their antioxidant activities. S-Equol, a metabolite of genistein and daidzein, has strong antioxidative effects; however, the ability to metabolize daidzein into S-equol varies based on racial and individual differences. The antioxidant activity of isoflavones may be effective in preventing dementia by inhibiting the phosphorylation of Alzheimer's-related tau proteins. Genistein also reduces allergic responses by limiting the expression of mast cell IgE receptors, which are involved in allergic responses. In addition, they have been known to prevent and treat various diseases, including cardiovascular diseases, metabolic syndromes, osteoporosis, diabetes, brain-related diseases, high blood pressure, hyperlipidemia, obesity, and inflammation. Further, it also has positive effects on menstrual irregularity in non-menopausal women and relieving menopausal symptoms in middle-aged women. Recently, soybean consumption has shown steep increasing trend in Western countries where the intake was previously only 1/20-1/50 of that in Asian countries. In this review, I have dealt with the latest research trends that have shown substantial interest in the biological efficacy of isoflavones in humans and plants, and their related mechanisms.

Production of Bovine Equol-Enriched Milk: A Review

Simple Summary

Milk and dairy products contain many substances beneficial to human health; moreover, the contents of some of these substances can be enhanced. This is also the case of isoflavones which are compounds of plant origin that can be ingested and metabolized by cattle and, subsequently, secreted into bovine milk. An especially healthful substance called equol is ranked among isoflavone metabolites, commonly produced in the digestive tract of cattle. Equol content in milk can be modified by using feedstuffs with different contents of isoflavones or by milk processing and storage.

Abstract

Milk and dairy products are important sources of nutrients in the human diet because they contain a number of essential substances and other biologically active components. Many of these substances can be modified, and thus offer opportunities to use milk and dairy products as functional food. Isoflavones are particularly important in human nutrition due to their diverse pharmacological and antioxidant properties. The clinical effectiveness of isoflavone-rich products is believed to be dependent on their ability to metabolize daidzein to equol, which may directly exert cancer preventive effects. However, only approximately 30–40% of humans are able to produce equol, while animals, in general, produce equol. Equol is the predominant product of bacterial metabolism of isoflavones and can be found in various amounts in some food of animal origin, especially in milk. Therefore, milk and dairy products can be considered to be sources of equol for humans who are not able to produce this metabolite. When the content of isoflavones in milk is to be modified, two groups of factors should be considered, i.e., dietary factors that include the source of isoflavones and the processing effects on feedstuffs and animal factors that include the intake of isoflavones, ruminal and postruminal changes, and the health and physiological status of animals. The approximate content of isoflavones in milk can be predicted using carry-over rates for different dietary sources or using a formula that describes the relationship between equol concentration in milk and formononetin intake. Processing and storage can affect the content and profile of isoflavones in milk and dairy products.