Dietary phytoestrogens and plasma lipids in Dutch postmenopausal women; a cross-sectional study

Hyperlipoproteinemia (a) and Phytoestrogen Therapy in Dialysis Patients: A Review

PURPOSE

Hyperlipoproteinemia (a) is a prevalent complication in dialysis patients, with no valid treatment strategy. The aim of this narrative review was to investigate the clinical significance of hyperlipoproteinemia (a) and phytoestrogen therapy in dialysis patients.

METHODS

A comprehensive literature search of the published data was performed regarding the effects of phytoestrogen therapy on hyperlipoproteinemia (a) in dialysis patients.

FINDINGS

Hyperlipoproteinemia (a) occurs in dialysis patients due to decreased catabolism and increased synthesis of lipoprotein (a) [Lp(a)]. A few clinical trials have studied the effects of phytoestrogens on serum Lp(a). All studies of dialysis patients or nonuremic individuals with hyperlipoproteinemia (a), except one, showed that phytoestrogens could significantly reduce serum Lp(a) levels. However, all investigations of phytoestrogen therapy in individuals with normal serum Lp(a) levels showed that it had no effect on serum Lp(a). Phytoestrogens seem to have effects similar to those of estrogen in lowering Lp(a) concentrations.

IMPLICATIONS

Considering the high prevalence of hyperlipoproteinemia (a) in dialysis patients, phytoestrogen therapy is a reasonable approach for reducing serum Lp(a) levels and its complications in these patients.

Dietary phytoestrogens and total and cause-specific mortality: results from 2 prospective cohort studies

BACKGROUND

Evidence regarding dietary phytoestrogens in relation to mortality remains limited.

OBJECTIVES

The objective of the study is to examine the associations of intake of isoflavones, lignans, and coumarins with total and cause-specific mortality in US males and females.

METHODS

We followed 75,981 females in the Nurses' Health Study (1984-2018) and 44,001 males in the Health Professionals Follow-up Study (1986-2018), who were free of cardiovascular disease (CVD), diabetes, or cancer at baseline. Their diet was repeatedly assessed using validated food frequency questionnaires every 2-4 y. Associations with mortality were assessed using time-dependent Cox models with adjustments for demographics, dietary and lifestyle factors, and medical history.

RESULTS

During 3,427,156 person-years of follow-up, we documented 50,734 deaths, including 12,492 CVD deaths, 13,726 cancer deaths, and 24,516 other non-CVD and noncancer deaths. After multivariable adjustment, the higher total phytoestrogen intake was associated with lower risk of total CVD and other non-CVD and noncancer mortality: comparing extreme quintiles, the pooled HRs (95% CIs) were 0.89 (0.87, 0.92), 0.90 (0.85, 0.96), and 0.86 (0.82, 0.90), respectively. We did not find a significant association with cancer mortality [0.97 (0.92, 1.03)]. For individual phytoestrogens in relation to total mortality, the pooled HRs (95% CIs) comparing extreme quintiles were 0.90 (0.87, 0.92) for isoflavones, 0.93 (0.90, 0.96) for lignans, and 0.93 (0.90, 0.95) for coumarins. Individual phytoestrogens were also significantly associated with lower risk of CVD mortality and other types of mortality. Primary food sources of phytoestrogens, including tofu, soy milk, whole grains, tea, and flaxseed, were also inversely associated with total mortality.

CONCLUSIONS

A higher intake of total phytoestrogens, including isoflavones, lignans, and coumarins, and foods rich in these compounds was associated with lower risk of total and certain cause-specific mortality in generally healthy US adults. These data suggest that these phytochemicals and their dietary sources may be integrated into an overall healthy diet to achieve a longer life span.

Dietary supplementation for female infertility: Recent advances in the nutritional therapy for premature ovarian insufficiency

Premature ovarian insufficiency (POI) ranks top in the reproductive disorders that may impair multiple functioning systems, reduce the quality of life and ultimately deprive patients of their fertility among women. Symptoms can be partially alleviated by present hormone replacement therapy that cannot improve conception or decrease occurrence rates of systemic complication. Nutritional dietary supplements are attracting more and more attention because of their safety, bioavailability, and efficacy for well-being. Nutrients in the daily food are composed of carbohydrates, fat and lipoprotein, protein and polypeptide, vitamins, and vegetable or fruits containing phytoestrogens. These are functional nutrients due to the proliferative, anti-inflammatory, anti-oxidant, and mitochondria-protective potential during the course of menopause. Apart from dietary nutrients, microbe-related nutritional substances, including probiotics, prebiotics and the combination-synbiotics, display high potential as well in supporting estrous cycle, ovarian viability and modulating other vital reproductive functions. The present review will discuss dietary and microbial nutrients and their roles and applications in the living body based upon animal or human research, evaluate possible effect mechanisms from molecular, cellular and tissue levels, and provide insights into nutritional therapy for prolonging reproductive lifespan in female patients.

Lignan Intake and Risk of Coronary Heart Disease

BACKGROUND

Evidence regarding lignan consumption in relation to coronary heart disease (CHD) risk remains limited and mixed.

OBJECTIVES

The aim of this study was to prospectively examine associations between lignan intake and CHD risk in U.S. men and women.

METHODS

We prospectively followed 214,108 men and women in 3 cohorts who did not have cardiovascular disease or cancer at baseline. Diet was repeatedly assessed using a validated food frequency questionnaire every 2-4 years since baseline.

RESULTS

During 5,517,225 person-years of follow-up, we documented 10,244 CHD cases, including 6,283 nonfatal myocardial infarction and 3,961 fatal CHD cases. In multivariable-adjusted analyses, comparing extreme quintiles, the pooled hazard ratios of CHD were 0.85 (95% CI: 0.79-0.92) for total lignans, 0.76 (95% CI: 0.71-0.82) for matairesinol, 0.87 (95% CI: 0.81-0.93) for secoisolariciresinol, 0.89 (95% CI: 0.83-0.95) for pinoresinol, and 0.89 (95% CI: 0.83-0.95) for lariciresinol (all P values for trend ≤0.003). Nonlinear relationships were found for total lignan, matairesinol, and secoisolariciresinol: the risk reduction plateaued at intakes above approximately 300 μg/d, 10 μg/d, and 100 μg/d, respectively (P < 0.01 for all nonlinearity). The inverse associations for total lignan intake appeared to be more apparent among participants with higher total fiber intake (P = 0.04 for interaction). In addition, lignan intake was more strongly associated with plasma concentrations of enterolactone when fiber intake was higher.

CONCLUSIONS

Increased long-term intake of lignans was associated with a significantly lower risk of total CHD in both men and women. Possible synergistic effects may exist between lignan and fiber intake in relation to CHD risk reduction, possibly through enhancing the production of enterolignans.

Effects of soy isoflavones on serum lipids and lipoprotein (a) in peritoneal dialysis patients

BACKGROUND AND AIM

Lipid abnormalities are common in peritoneal dialysis (PD) patients and no effective treatment to decrease serum lipoprotein (a) [Lp(a)] in dialysis patients is known so far. Therefore, this research was designed to investigate the effects of soy isoflavone supplement on serum lipids and Lp(a) in PD patients.

METHODS & RESULTS

In this randomized, double-blind, placebo-controlled trial, 40 PD patients were randomly assigned to either the isoflavone or the placebo group. The patients in the isoflavone group received 100 mg soy isoflavone daily for 8 weeks, whereas the placebo group received corresponding placebos. At baseline and the end of the 8th week, 7 mL of blood was obtained from each patient and serum triglycerides, total cholesterol, low density lipoprotein-cholesterol (LDL-C), high density lipoprotein-cholesterol (HDL-C), and Lp(a) were measured. Serum Lp(a) reduced significantly up to 10% in the isoflavone group at the end of week 8 compared to baseline (P < 0.05), and the reduction was significant in comparison with the placebo group (P < 0.05). Serum HDL-C increased significantly up to 11.5% in the isoflavone group at the end of week 8 compared to baseline (P = 0.05), and the increment was significant in comparison with the placebo group (P < 0.05). There were no significant differences between the two groups in mean changes of serum triglycerides, total cholesterol, and LDL-C.

CONCLUSIONS

This study indicates that daily administration of 100 mg soy isoflavones reduces serum Lp(a) and increases HDL-C concentration which are two determinants of cardiovascular disease in PD patients. CLINICALTRIALS.GOV: NCT03773029.

REGISTRATION NUMBER AND DATE

NCT03773029 - 2018.

Lignans' Potential in Pre and Post-onset Type 2 Diabetes Management

INTRODUCTION

Type 2 Diabetes (T2D) cases continue to rise dramatically despite efforts to get people to exercise and eat with a view to health and combatting the cluster of 7 issues (central obesity (elevated waist circumference), hyperglycaemia, hypertension, dyslipidemia, pro-thrombotic state, increased oxidation (including Low-density Lipoprotein (LDL)) and the pro-inflammatory state associated with pre- and post-onset T2D.

BACKGROUND

There are numerous medications available to deal with these seven major issues. However, each medication currently available manages a maximum of two cluster members at a time. Consequently, polypharmacy is frequently required to manage the cluster of seven. Polypharmacy brings with it high financial costs for numerous medications, the risk of poor compliance (particularly so in older patients), side effects and drug interactions. Thus, there is a search for new agents that reduce the high costs and risks of polypharmacy while at the same time combatting three or more of the cluster of seven. There is very limited evidence to suggest that one or more lignans may efficaciously and safely, in the short and long term, manage at least three of the cluster of seven, pre- and post-T2D onset, thus reducing polypharmacy. However, multi-centre, large clinical trials are required before any definitive conclusions about these lignans can be reached regarding their safe and efficacious polypharmacy reduction potential, both long and short-term, in pre and post-onset T2D management.

CONCLUSION

It is concluded that some lignans appear to have the potential to manage at least three members of the cluster of seven in pre- or post-T2D onset and hence reduce polypharmacy but much more investigation is required to confirm if such is the case. At the moment, there is not enough evidence that any of the lignans will, in the long or short term, safely and efficaciously manage the cluster of seven via polypharmacy reduction.

Urinary enterolignan concentrations are positively associated with serum HDL cholesterol and negatively associated with serum triglycerides in U.S. adults

Fiber-rich diets are associated with favorable lipid profiles, but the specific compounds and the mechanisms behind this effect are yet to be fully understood. Lignans are fiber-related polyphenols that have been associated with lower prevalence of cardiovascular disease. The objective of this study was to investigate the relationship between dietary lignan exposure, measured as the urinary concentration of their metabolites, enterolactone and enterodiol, and serum lipids in a representative sample of U.S. adults. We carried out a cross-sectional analysis of data from 1492 adults who participated in the 1999-2004 NHANES. The mean urinary concentration of enterolignans in U.S. adults was 1.9 μmol/L. The multivariate-adjusted mean differences comparing the highest and lowest enterolignan tertile were 0.06 mmol/L for HDL cholesterol and -0.17 mmol/L for TG (P < 0.05). In spline regression models, we also found an inverse association between serum TG and urinary enterolignan concentrations. Serum HDL cholesterol levels increased linearly with increasing enterolignan concentrations. Modest or no associations were found between enterolignan concentrations and serum LDL cholesterol or total cholesterol. In conclusion, enterolignan concentrations are associated with lower serum TG concentrations and greater HDL cholesterol concentrations in U.S. adults.

Rapid simultaneous determination of isoflavones in Radix puerariae using high-performance liquid chromatography-triple quadrupole mass spectrometry with novel shell-type column

A high-performance liquid chromatography (HPLC) coupled with triple quadrupole mass spectrometry (MS/MS) method was developed for rapid determination of 13 isoflavones in Radix puerariae. A novel shell-type column, namely Kinetex core-shell C(18) column (50 mm×2.1 mm id, 2.6 μm), and gradient elution were used during the analysis. The chromatographic peaks of 13 investigated compounds were identified by comparing their retention time and MS data with the related reference compounds. Multiple-reaction monitoring (MRM) was employed for the quantitative analysis with negative ionization mode. All calibration curves showed good linearity (r(2)>0.9990) within test ranges. The LOD and LOQ were lower than 0.017 and 0.873 μg/mL on column, respectively. The intra- and inter-day precisions for 13 analytes were <1.17 and 2.17%, respectively, and the recoveries were 93.1-104.4%. The validated method was applied for quantitative analysis of 13 isoflavones in 7 species of Radix puerariae. The result demonstrated that HPLC-MS/MS system with Kinetex column could be a promising analytical tool for the determination of isoflavones in traditional Chinese medicines, which is helpful for comprehensive evaluation of quality of R. puerariae.

Dietary lignans: physiology and potential for cardiovascular disease risk reduction

The present review of the literature on lignan physiology and lignan intervention and epidemiological studies was conducted to determine if lignans decrease the risks of cardiovascular disease in Western populations. Five intervention studies using flaxseed lignan supplements indicated beneficial associations with C-reactive protein, and a meta-analysis that included these studies also suggested lignans have a lowering effect on plasma total and low-density lipoprotein cholesterol. Three intervention studies using sesamin supplements indicated possible lipid- and blood pressure-lowering associations. Eleven human observational epidemiological studies examined dietary intakes of lignans in relation to cardiovascular disease risk. Five showed decreased risk with either increasing dietary intakes of lignans or increased levels of serum enterolactone (an enterolignan used as a biomarker of lignan intake), five studies were of borderline significance, and one was null. The associations between lignans and decreased risk of cardiovascular disease are promising, but they are yet not well established, perhaps due to low lignan intakes in habitual Western diets. At the higher doses used in intervention studies, associations were more evident.

Soy extract phytoestrogens with high dose of isoflavones for menopausal symptoms

AIM

The aim of the present study was to assess the efficacy and safety of a standardized compound based on an extract of soy phytoestrogens, with high doses of isoflavones in the management of menopausal hot flushes.

METHODS

A total of 180 women aged 40-65 years with a minimum of five moderate-to-severe hot flushes in the last 7 days at baseline and absence of menstruation for at least 6 months participated in a 12-week prospective, randomized, double-blind, placebo-controlled multicenter trial. After a 2-week run-in period, women received one tablet a day of 80 mg isoflavones (corresponding to 60 mg of genistein) or a matching placebo.

RESULTS

The mean daily number of moderate-to-severe hot flushes decreased in both study groups, but the reduction was greater in the isoflavones arm at 6 (36.2%) and 12 weeks (41.2%) than in the placebo arm (24.0% at 6 weeks, 29.3% at 12 weeks), with a difference of 1.1 (95% CI [-2.0 to -0.06]) (P = 0.038) at 6 weeks and 1.1 (95% CI [-2.05 to -0.15]) (P = 0.023) at 12 weeks. Similar findings were obtained for hot flushes of any intensity. The Kupperman index decreased in both study groups. Relief of hot flushes was greater when time to menopause was >or=12 months and in cases of BMI >or=27 kg/m(2).

CONCLUSION

In daily practice conditions, high doses of isoflavones, particularly genistein, can be used for the management of hot flushes in postmenopausal women not treated with hormone replacement therapy due to their superior efficacy to placebo and very good safety profile.

Role of exercise and nutrition in menopause

Menopause and the aging process itself cause many physiologic changes, which explain the increased prevalence of chronic diseases observed in postmenopausal women. Exercise and nutrition play important roles in the prevention and treatment of cardiovascular disease, cancer, obesity, diabetes, osteoporosis, and depression.

Inulin-enriched pasta affects lipid profile and Lp(a) concentrations in Italian young healthy male volunteers

BACKGROUND

Inulin has been suggested to have beneficial effects on lipids, especially on triglyceridemia. Few data are available about the effects of inulin on Lipoprotein(a), a low-density lipoprotein-like particle considered as an independent risk factor for atherosclerosis. Adding inulin to pasta could be a preventive strategy for delaying the onset of atherosclerosis.

AIM OF THE STUDY

was to evaluate the effects of inulin-enriched pasta on lipid profile and on Lipoprotein(a) in young healthy subjects.

METHODS

Twenty-two young healthy male volunteers entered a randomized double blind cross-over study consisting of a 2-weeks run-in period, a baseline assessment, two 5-weeks study periods (11% inulin-enriched or control pasta), and an 8-weeks wash-out period in between. Serum lipid concentrations were evaluated by routine biochemical analyses and plasma Lipoprotein(a) concentrations by ELISA. The size of apolipoprotein(a) isoforms was determined by Western blot and immunodetection.

RESULTS

Significant differences at baseline and in the treatment groups were found for HDL-cholesterol (P = 0.004), total cholesterol/HDL-cholesterol ratio (P = 0.006), triglycerides (P = 0.04), and Lipoprotein(a) (P = 0.02) concentrations (data analyzed by Friedman test). Dunn's multiple comparison test was used to assess the significance of differences between inulin-enriched pasta diet vs. baseline. HDL-cholesterol concentrations increased by 35.9%; total cholesterol/HDL-cholesterol ratio, triglycerides, and Lipoprotein(a) concentrations decreased by 22.2, 23.4, and 16.5% respectively.

CONCLUSIONS

Inulin-enriched pasta administration induced significant effects on lipid pattern parameters in young healthy volunteers, including a significant reduction in Lipoprotein(a) concentrations.

Isoflavones--safe food additives or dangerous drugs?

The sales volume of products containing isoflavone has increased since the publication of the Women's Health Initiative. The many apparently contradictory results published on the effects of isoflavones on a variety of estrogen-regulated organs point to both beneficial as well as adverse effects on human health. It is of particular importance that psychovegetative climacteric complaints such as hot flushes are, if at all, only slightly influenced by isoflavones. The substances appear to have weak anti-osteoporotic effect. Their anti-atherosclerotic action is debatable, as not all authors find any beneficial effect on lipids. Most importantly, there is dispute as to whether isoflavones derived from soy or red clover have negative, positive or any effect at all on the mammary gland or endometrium. It is beyond any doubt that soy products may have cancer preventing properties in a variety of organs including the mammary gland. However, these properties may only be exerted if the developing organ was under the influence of isoflavones during childhood and puberty. This may also explain the often quoted "Japanese Phenomenon", the fact that breast cancer occurs to a lesser extent in Japanese women. When administered to isoflavone "inexperienced" women at the time of menopause, the phytoestrogens appear to share the same effects as estrogen used in classical preparations for hormone replacement therapy, i.e. they may stimulate the proliferation of endometrial and mammary gland tissue with at present unknown and unpredictable risk to these organs. Therefore, the following question arises for the clinician: Why should soy or red clover products containing isoflavone be recommended, if the positive effects are only negligible but the adverse effects serious?

Effect of 6 months of exercise and isoflavone supplementation on clinical cardiovascular risk factors in obese postmenopausal women: a randomized, double-blind study

OBJECTIVE

To investigate whether 6 months of exercise combined with isoflavone supplementation could improve clinical risk factors that predispose to cardiovascular disease in obese postmenopausal women.

DESIGN

This was a randomized, double-blind, controlled trial in which 50 healthy obese postmenopausal women were divided into two groups and assigned to isoflavone supplementation (n=25) or a placebo (n=25) for 1 year. For the last 6 months, both groups participated in an exercise program (three times per week), at the end of which cardiovascular disease risk factors were compared between groups. Body composition (using dual-energy x-ray absorptiometry), metabolic profile (blood lipids, fasting insulin, fasting glucose, sex hormone-binding globulin, C-reactive protein) were determined at baseline and at 6 and 12 months.

RESULTS

We observed a significant effect of exercise and isoflavone supplementation on body weight, total and abdominal fat mass (kilograms and percentage), body mass index, appendicular fat-free mass, fat-free mass/fat mass ratio, and sex hormone-binding globulin, but not with exercise alone. No difference was observed for other biochemical characteristics, although the quantitative insulin sensitivity check index increased equally in both groups. Conversely, although not significant, we observed a tendency for a treatment effect on body mass index (P=0.07) and on absolute (kilograms) (P=0.07) and percentage of (P=0.053) abdominal fat mass, whereas no effect of treatment was found for other variables using the Mann-Whitney test.

CONCLUSIONS

Compared to an aerobic exercise program alone, 70 mg/day of isoflavones combined with exercise may promote significant improvements in body composition parameters that are known to influence cardiovascular disease risk in postmenopausal women.

Whole grains and CVD risk

There is an increasing body of evidence, including that from prospective population studies and epidemiological observational studies, suggesting a strong inverse relationship between increased consumption of wholegrain foods and reduced risk of CVD. This evidence has translated into specific dietary recommendations in the USA to consume at least three servings of whole grain per d, and has informed the development of specific health claims for wholegrain foods both in the USA and in Europe. Wholegrain foods are rich sources of many nutrients and phytochemicals, including complex carbohydrates, dietary fibre, minerals, vitamins, antioxidants and phyto-oestrogens such as lignans. Many of these components are lost from the grain during processing and although some may be replaced (such as in the mandatory fortification of white flour), this practice ignores the possible synergistic effects of the ‘natural’ constituents. The notion that wholegrain foods are simply a source of dietary fibre has been dispelled, although the additional components that contribute to the health benefits have not been clearly identified. In addition, the mechanisms by which wholegrain foods may have their effect are poorly understood. At present there are few strictly-controlled intervention studies that have confirmed a beneficial effect of increased consumption of wholegrain foods, demonstrated the level of consumption required to elicit a beneficial effect or provided evidence of modes of action. Although wholegrain foods are considered amongst the healthiest food choices available, their consumption falls well below current recommendations, which have been based mainly on epidemiological evidence. Well-controlled intervention studies are needed to provide more detailed mechanistic evidence to support the health claims and findings which can be used to develop effective public health strategies to promote whole-grain consumption.

Serum enterolactone concentration and the risk of coronary heart disease in a case-cohort study of Finnish male smokers

The lignan enterolactone produced by the intestinal microflora from dietary precursors has been hypothesized to protect against coronary heart disease. The present study examined the association between serum enterolactone concentration and the risk of coronary heart disease. A prospective case-cohort study was conducted among male smokers randomized to receive a placebo supplement in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study (1986-1999). Serum enterolactone concentrations were measured by the gas chromatography-mass spectrometry method in serum collected at trial baseline from 340 men diagnosed with nonfatal myocardial infarction (n = 205) or coronary death (n = 135) during follow-up and from the randomly selected subcohort of 420 subjects. The classic risk factors-adjusted rate ratios for all coronary heart disease events in increasing quintiles of enterolactone were 1.00 (referent), 0.85 (95% confidence interval (CI): 0.51, 1.43), 0.59 (95% CI: 0.35, 1.00), 0.69 (95% CI: 0.40, 1.16), and 0.63 (95% CI: 0.33, 1.11), and the p(trend) was 0.07. For the highest versus the lowest quintile of enterolactone, the rate ratios for nonfatal myocardial infarction and coronary death were 0.67 (95% CI: 0.37, 1.23; p(trend) = 0.10) and 0.57 (95% CI: 0.26, 1.25; p(trend) = 0.18), respectively. In conclusion, only weak support for the association between serum enterolactone concentration and coronary heart disease was found.

Phytoestrogens: end of a tale?

Phytoestrogens are plant-derived hormone-like diphenolic compounds of dietary origin that are present at high levels in plasma of subjects living in areas with low atherosclerosis and cancer incidence. The term phytoestrogen is commonly applied to the soy isoflavones genistein, daidzein and glycitein. As outlined in a previous review article in this journal by Adlercreutz and Mazur 1, these compounds are weakly estrogenic and appear to influence the cardiovascular system, the production, metabolism and biological activity of sex-hormones, as well as malignant cell proliferation, differentiation and angiogenesis. Recently skepticism has developed concerning the true potential of phytoestrogens to beneficially modify these processes. A critical analysis of the early findings from supplementing the diet with soy protein has failed to confirm phytoestrogens as the responsible agent for beneficial cardiovascular effects, be it by way of lipid reduction, vasodilation or lipoprotein oxidation. Furthermore, contrasting data have been reported on the potential of phytoestrogens to prevent hormone-dependent cancers (e.g. breast and prostate) and to successfully treat post-menopausal complaints, an indication for which they are widely used. These potentially negative findings have led health authorities in several countries to suggest maximum daily intake levels for phytoestrogens. There is now growing interest in the use of soy products containing low levels of phytoestrogens and in research on other phytoestrogen free legumes such as lupin.