Effect of Dietary Flaxseed Intake on Circulating Sex Hormone Levels among Postmenopausal Women: A Randomized Controlled Intervention Trial

An insight into the anticancer potentials of lignan arctiin: A comprehensive review of molecular mechanisms

Natural products are being developed as possible treatment options due to the rising prevalence of cancer and the harmful side effects of synthetic medications. Arctiin is a naturally occurring lignan found in numerous plants and exhibits different pharmacological activities, along with cancer. To elucidate the anticancer properties and underlying mechanisms of action, a comprehensive search of various electronic databases was conducted using appropriate keywords to identify relevant publications. The findings suggest that arctiin exhibits anticancer properties against tumor formation and various cancers such as cervical, myeloma, prostate, endothelial, gastric, and colon cancers in several preclinical pharmacological investigations. This naturally occurring compound exerts its anticancer effect through different cellular mechanisms, including mitochondrial dysfunction, cell cycle at different phases (G2/M), inhibition of cell proliferation, apoptotic cell death, and cytotoxic effects, as well as inhibition of migration and invasion of various malignant cells. Moreover, the study also revealed that, among the various cellular pathways, arctiin was shown to be more potent in terms of the PI3K/AKT and JAK/STAT signaling pathways. However, pharmacokinetic investigation indicated the compound's poor oral bioavailability. Because of these findings, arctiin might be considered a promising chemotherapeutic drug candidate.

Are oilseeds a new alternative protein source for human nutrition?

This review focuses on the potential use, nutritional value and beneficial health effects of oilseeds as a source of food protein. The process of extracting oil from oilseeds produces a by-product that is rich in proteins and other valuable nutritional and bioactive components. This product is primarily used for animal feed. However, as the demand for proteins continues to rise, plant-based proteins have a real success in food applications. Among the different plant protein sources, oilseeds could be used as an alternative protein source for human diet. The data we have so far show that oilseeds present a protein content of up to 40% and a relatively well-balanced profile of amino acids with sulphur-containing amino acids. Nevertheless, they tend to be deficient in lysine and rich in anti-nutritional factors (ANFs), which therefore means they have lower anabolic potential than animal proteins. To enhance their nutritional value, oilseed proteins can be combined with other protein sources and subjected to processes such as dehulling, heating, soaking, germination or fermentation to reduce their ANFs and improve protein digestibility. Furthermore, due to their bioactive peptides, oilseeds can also bring health benefits, particularly in the prevention and treatment of diabetes, obesity and cardiovascular diseases. However, additional nutritional data are needed before oilseeds can be endorsed as a protein source for humans.

Phytonutrients and outcomes following breast cancer: a systematic review and meta-analysis of observational studies

BACKGROUND

Phytonutrient intakes may improve outcomes following breast cancer, but the impact of postdiagnosis introduction vs established prediagnostic exposure as well as optimum doses has not been established. Evidence from observational studies for key exposures was evaluated, including dosage and intake time frames.

METHODS

MEDLINE, EMBASE, CINAHL, Cochrane Library, ClinicalTrials.gov, and the ISRCTN registry were searched for prospective and retrospective observational studies investigating the impact of soybean, lignans, cruciferous (cabbage-family) vegetables, green tea, or their phytonutrients on breast cancer survival outcomes. A random-effects model was used to calculate summary hazard ratios (HRs) and 95% confidence intervals (CIs). Nonlinear dose-response analyses were conducted using restricted cubic splines.

RESULTS

Thirty-two articles were included. Soy isoflavones were associated with a 26% reduced risk of recurrence (HR = 0.74, 95% CI = 0.60 to 0.92), particularly among postmenopausal (HR = 0.72, 95% CI = 0.55 to 0.94) and estrogen receptor-positive survivors (HR = 0.82, 95% CI = 0.70 to 0.97), with the greatest risk reduction at 60 mg/day. In mortality outcomes, the reduction was mostly at 20 to 40 mg/day. Soy protein and products were inversely associated with cancer-specific mortality for estrogen receptor-positive disease (HR = 0.75, 95% CI = 0.60 to 0.92). An inverse association was observed for serum or plasma enterolactone, measured prediagnosis and early postdiagnosis, with cancer-specific mortality (HR = 0.72, 95% CI = 0.58 to 0.90) and all-cause mortality (HR = 0.69, 95% CI = 0.57 to 0.83). No effects were observed for cruciferous vegetables. There was a 44% reduced risk of recurrence with prediagnostic green tea for stage I and II breast cancer (HR = 0.56, 95% CI = 0.38 to 0.83).

CONCLUSIONS

Soy, enterolactone, and green tea demonstrated significant risk reductions in outcomes following breast cancer. Evidence is needed regarding the impact of postdiagnostic introduction or substantial increase of these exposures.

Anti-Cancer Properties of Flaxseed Proteome

Flaxseed has been recognized as a valuable source of nutrients and bioactive compounds, including proteins that possess various health benefits. In recent years, studies have shown that flaxseed proteins, including albumins, globulins, glutelin, and prolamins, possess anti-cancer properties. These properties are attributed to their ability to inhibit cancer cell proliferation, induce apoptosis, and interfere with cancer cell signaling pathways, ultimately leading to the inhibition of metastasis. Moreover, flaxseed proteins have been reported to modulate cancer cell mechanobiology, leading to changes in cell behavior and reduced cancer cell migration and invasion. This review provides an overview of the anti-cancer properties of flaxseed proteins, with a focus on their potential use in cancer treatment. Additionally, it highlights the need for further research to fully establish the potential of flaxseed proteins in cancer therapy.

The effect of flaxseed supplementation on sex hormone profile in adults: a systematic review and meta-analysis

Inconsistent data suggest that flaxseed supplementation may have a role in sex hormones. We aimed to carry out a systematic review and meta-analysis of randomized controlled trials (RCTs) investigating effects of flaxseed supplementation on sex hormone profile. PubMed, Scopus, Embase, Cochrane Library, Web of Science databases, and Google Scholar were searched up to March 2023. Standardized mean difference (SMD) was pooled using a random-effects model. Sensitivity analysis, heterogeneity, and publication bias were reported using standard methods. The quality of each study was evaluated with the revised Cochrane risk-of-bias tool for randomized trials, known as RoB 2. Finding from ten RCTs revealed that flaxseed supplementation had no significant alteration in follicle-stimulating hormone (FSH) (SMD: -0.11; 95% CI: -0.87, 0.66: p = 0.783), sex hormone-binding globulin (SHBG) (SMD: 0.35; 95% CI: -0.02, 0.72; p = 0.063), total testosterone (TT) levels (SMD: 0.17; 95% CI: -0.07, 0.41; p = 0.165), free androgen index (FAI) (SMD = 0.11, 95% CI: -0.61, 0.83; p = 0.759), and dehydroepiandrosterone sulfate (DHEAS) (SMD: 0.08, 95%CI: -0.55, 0.72, p = 0.794). Flaxseed supplementation had no significant effect on sex hormones in adults. Nevertheless, due to the limited included trials, this topic is still open and needs further studies in future RCTs.

Proliferative response of ERα-positive breast cancer cells to 10 μM enterolactone, and the associated alteration in the transcriptomic landscape

Enterolactone (EL) is a product of gut-microbial metabolism of dietary plant lignans. Studies linking EL with breast cancer risk have bolstered investigations into its effects on the mammary epithelial cells, and the mechanisms thereof. While it binds to the estrogen receptor α; ERα, its effect on the proliferation of mammary tumor cell lines is reportedly ambivalent; depending on its concentration. The genomic correlates of EL actions also remain unexplored. Here we have elaborately studied the effect of EL on proliferation of ERα-positive, and ERα-negative cell lines. 10 µM EL significantly enhanced the growth of the ERα-positive MCF-7 or T47D breast cancer cells, but not the ERα-negative MDA-MB-231 or MDA-MB-453 cells. In MCF-7 cells, it significantly increased the expression of TFF1 mRNA, an estrogen-induced transcript. The binding of ERα to the estrogen response element within the TFF1 locus further demonstrated the pro-estrogenic effect of 10 µM EL. We further explored the genome-wide transcriptomic effect of 10 µM EL using the next generation sequencing technology (RNA-seq). Analysis of RNA-seq data obtained from vehicle (0.1% DMSO)- or 10 µM EL treated- MCF-7 cells revealed modulation of expression of diverse sets of functionally related genes, which reflected cell cycle progression. The manner in which 10 µM EL regulated the hallmark G2/M checkpoint, and estrogen-response-late genes correlated with proliferation inducing, and estrogen-like effects of EL on MCF-7 cells.

Influence of Flaxseed (Linum usitatissimum) on Female Reproduction

This review describes the chemical composition of flaxseed (Linum usitatissimum) and its general health effects, as well as the currently available knowledge concerning its action on the female reproductive state, functions on the ovary and ovarian cells and reproductive hormones, as well as possible constituents and extra- and intracellular mediators mediating its effects on female reproductive processes. Flaxseed contains a number of biologically active molecules, which, acting through multiple signalling pathways, can determine numerous physiological, protective and therapeutic effects of flaxseed. The available publications demonstrate the action of flaxseed and its constituents on the female reproductive system - ovarian growth, follicle development, the resulting puberty and reproductive cycles, ovarian cell proliferation and apoptosis, oo- and embryogenesis, hormonal regulators of reproductive processes and their dysfunctions. These effects can be determined by flaxseed lignans, alpha-linolenic acid and their products. Their actions can be mediated by changes in general metabolism, metabolic and reproductive hormones, their binding proteins, receptors and several intracellular signalling pathways, including protein kinases, transcription factors regulating cell proliferation, apoptosis, angiogenesis and malignant transformation. Flaxseed and its active molecules are found potentially useful for improving farm animal reproductive efficiency and treatment of polycystic ovarian syndrome and ovarian cancer.

The Role of Flaxseed in Improving Human Health

Flaxseed contains high amounts of biologically active components such as α-linolenic acid, lignans, and dietary fiber. Due to its numerous nutritional properties, flaxseed has been classified as a "superfood", that is, a food of natural origin with various bioactive components and many health-promoting benefits. Flaxseed consumption can be an important factor in the prevention of diseases, particularly related to nutrition. The regular consumption of flaxseed may help to improve lipid profile and lower blood pressure, fasting glucose, and insulin resistance index (HOMA-IR). Moreover, flaxseed is characterized by anticancer and antioxidant properties and can significantly reduce the intensity of symptoms associated with menopause, constipation, and mental fatigue, improve skin condition, and accelerate wound healing. In addition to its bioactive compounds, flaxseed also contains antinutrients such as cyanogenic glycosides (CGs), cadmium, trypsin inhibitors, and phytic acid that can reduce the bioavailability of essential nutrients and/or limit its health-promoting effects. Three common forms of flaxseed available for human consumption include whole flaxseed, ground flaxseed, and flaxseed oil. The bioavailability of ALA and lignans is also dependent on the form of flaxseed consumed. To ensure high bioavailability of its bioactive components, flaxseed should be consumed in the ground form.

Health benefits of flaxseed and its peptides (linusorbs)

Flaxseed (Linum usitatissimum L.) has been associated with numerous health benefits. The flax plant synthesizes an array of biologically active compounds including peptides or linusorbs (LOs, a.k.a., cyclolinopeptides), lignans, soluble dietary fiber and omega-3 fatty acids. The LOs arise from post-translational modification of four or more ribosome-derived precursors. These compounds exhibit an array of biological activities, including suppression of T-cell proliferation, excessive inflammation, and osteoclast replication as well as induction of apoptosis in some cancer cell lines. The mechanisms of LO action are only now being elucidated but these compounds might interact with other active compounds in flaxseed and contribute to biological activity attributed to other flax compounds. This review focuses on both the biological interaction of LOs with proteins and other molecules and comprehensive knowledge of LO pharmacological and biological properties. The physicochemical and nutraceutical properties of LOs, as well as the biological effects of certain LOs, and their underlying mechanisms of action, are reviewed. Finally, strategies for producing LOs by either peptide synthesis or recombinant organisms are presented. This review will be the first to describe LOs as a versatile scaffold for the action of compounds to deliver physiochemically/biologically active molecules for developing novel nutraceuticals and pharmaceuticals.

Urinary phthalate metabolite concentrations and serum hormone levels in pre- and perimenopausal women from the Midlife Women's Health Study

BACKGROUND

Phthalate exposure is associated with altered reproductive function, but little is known about associations between phthalate and hormone levels in midlife women.

METHODS

This cross-sectional analysis includes 45-54-year-old pre- and perimenopausal women from Baltimore, MD and its surrounding counties enrolled in the Midlife Women's Health Study (n = 718). Serum and urine samples were collected from participants once a week for four consecutive weeks to span the menstrual cycle. Serum samples were assayed for estradiol, testosterone, progesterone, sex hormone binding globulin (SHBG), follicle-stimulating hormone (FSH), and anti-Müllerian hormone (AMH), and geometric means were calculated for each hormone across all four weeks. Urine samples were analyzed for nine phthalate metabolites from pools of one-to-four urine samples. Phthalate metabolite concentrations were specific gravity-adjusted and assessed as individual metabolites or as molar sums of metabolites from common parents (di(2-ethylhexyl) phthalate metabolites, ∑DEHP), exposure sources (plastic, ∑Plastics; personal care products, ∑PCP), biological activity (anti-androgenic, ∑AA), and sum of all metabolites (∑Phthalates). We used linear regression models to assess overall associations of phthalate metabolites with hormones, controlling for important demographic, lifestyle, and health factors. We also explored whether associations differed by menopause status, body mass index (BMI), and race/ethnicity.

RESULTS

Most participants were non-Hispanic white (67%) or black (29%), college-educated (65%), employed (80%), and had somewhat higher mean urinary phthalate metabolite concentrations than other U.S. women. Overall, the following positive associations were observed between phthalate metabolites and hormones: ∑DEHP (%Δ: 4.9; 95%CI: 0.5, 9.6), ∑Plastics (%Δ: 5.1; 95%CI: 0.3, 10.0), and ∑AA (%Δ: 7.8; 95%CI: 2.3, 13.6) with estradiol; MiBP (%Δ: 6.6; 95%CI: 1.5, 12.1) with testosterone; ∑DEHP (%Δ: 8.3; 95%CI: 1.5, 15.6), ∑Plastics (%Δ: 9.8; 95%CI: 2.4, 17.7), MEP (%Δ: 4.6; 95%CI: 0.1, 9.2), ∑PCP (%Δ: 6.0; 95%CI: 0.2, 12.2), ∑Phthalates (%Δ: 9.0; 95%CI: 2.1, 16.5), and ∑AA (%Δ: 12.9; 95%CI: 4.4, 22.1) with progesterone; and MBP (%Δ: 8.5; 95%CI: 1.2, 16.3) and ∑AA (%Δ: 9.0; 95%CI: 1.3, 17.4) with AMH. Associations of phthalate metabolites with hormones differed by menopause status (strongest in premenopausal women for estradiol, progesterone, and FSH), BMI (strongest in obese women for progesterone), and race/ethnicity (strongest in non-Hispanic white women for estradiol and AMH).

CONCLUSIONS

We found that phthalate metabolites were positively associated with several hormones in midlife women, and that some demographic and lifestyle characteristics modified these associations. Future longitudinal studies are needed to corroborate these findings in more diverse midlife populations.

The Effects of Diet and Exercise on Endogenous Estrogens and Subsequent Breast Cancer Risk in Postmenopausal Women

Endogenous estrogens have been associated with overall breast cancer risk, particularly for postmenopausal women, and ways to reduce these estrogens have served as a primary means to decrease overall risk. This narrative review of clinical studies details how various nutritional and exercise lifestyle interventions have been used to modify estrogen levels and metabolism to provide a protective impact against breast cancer incidence. We also summarized the evidence supporting the efficacy of interventions, outcomes of interest and identified emerging research themes. A systematic PubMed MEDLINE search identified scholarly articles or reviews published between 2000-2020 that contained either a cohort, cross-sectional, or interventional study design and focused on the relationships between diet and/or exercise and overall levels of different forms of estrogen and breast cancer risk and occurrence. Screening and data extraction was undertaken by two researchers. Data synthesis was narrative due to the heterogeneous nature of studies. A total of 1625 titles/abstracts were screened, 198 full texts reviewed; and 43 met eligibility criteria. Of the 43 studies, 28 were randomized controlled trials, and 15 were observational studies. Overall, studies that incorporated both diet and exercise interventions demonstrated better control of detrimental estrogen forms and levels and thus likely represent the best strategies for preventing breast cancer development for postmenopausal women. Some of the strongest associations included weight loss via diet and diet + exercise interventions, reducing alcohol consumption, and consuming a varied dietary pattern, similar to the Mediterranean diet. More research should be done on the effects of specific nutritional components on endogenous estrogen levels to understand the effect that the components have on their own and in combination within the diet.

Dietary Lignans: Definition, Description and Research Trends in Databases Development

The study aims to communicate the current status regarding the development and management of the databases on dietary lignans; within the phytochemicals, the class of the lignan compounds is of increasing interest because of their potential beneficial properties, i.e., anticancerogenic, antioxidant, estrogenic, and antiestrogenic activities. Furthermore, an introductory overview of the main characteristics of the lignans is described here. In addition to the importance of the general databases, the role and function of a food composition database is explained. The occurrence of lignans in food groups is described; the initial construction of the first lignan databases and their inclusion in harmonized databases at national and/or European level is presented. In this context, some examples of utilization of specific databases to evaluate the intake of lignans are reported and described.