Randomised, controlled, cross-over trial of soy protein with isoflavones on blood pressure and arterial function in hypertensive subjects

Association between PEMT rs7946 and blood pressure levels in Chinese adolescents

OBJECTIVES

This study was to explore blood pressure levels in Chinese adolescents with different genotypes of phosphatidylethanolamine N-methyltransferase (PEMT) gene (PEMT) rs7946, as well as effects of dietary intake on blood pressure levels with different genders and different genotypes of PEMT rs7946.

METHODS

PEMT rs7946 genotypes were identified by PCR-restriction fragment length polymorphism and verified by DNA sequencing. Blood pressure was measured using a standard mercury sphygmomanometer. Dietary intakes were analyzed based on a 3-day diet diary, and dietary components were calculated using computer software.

RESULTS

A total of 721 high school students (314 males and 407 females) at the age of 16.86 ± 0.59 years were included. The A allele carriers of PEMT rs7946 had increased levels of SBP, DBP, mean arterial pressure (MAP) and pulse pressure (PP) than the GG homozygotes in the female subjects. There were significant interactions between PEMT rs7946 and gender on SBP and MAP levels, regardless of whether an unadjusted or adjusted model was used. When dietary intake was taken into account, fat intake was positively associated with SBP and PP in the male GG homozygotes, while protein intake was positively associated with PP in the female A allele carriers of PEMT rs7946.

CONCLUSION

This study suggests that PEMT rs7946 is significantly associated with blood pressure levels in human being. There might be interactions among PEMT rs7946, gender, and dietary intake on blood pressure levels in the adolescent population.

The Inverse Association Between Isoflavone Intake and Prevalence of Metabolic Syndrome: A Cross-Sectional Study from National Health and Nutrition Examination Survey

Objective: Metabolic syndrome (MetS) is a global disease burden that has resulted in 10 million people being affected by it, yet no new drugs have been approved for clinical treatment. Isoflavone may be able to stop the development of MetS or enhance its treatment. Therefore, we investigated the relationship between dietary intake of isoflavone and prevalence of MetS to find potentially effective treatments. Methods: We conducted a cross-sectional study using data from 8512 National Health and Nutrition Examination Survey (NHANES) participants from 2007 to 2010 and 2017 to 2018 and their associated isoflavone intake from the flavonoid database in the USDA Food and Nutrient Database for Dietary Studies (FNDDS). We investigated the relationship between MetS status and isoflavone intake by adjusting for confounding variables using multivariable logistic regression models. Results: In a multivariable-adjusted model, there was a negative association between isoflavone intake and the incidence of MetS (odds ratio for Q4 vs. Q1 was 0.66, 95% confidence interval = 0.51-0.86, P = 0.003, p for trend was <0.001). This inverse association remained robust across most subgroups, while nonsignificant interactions were tested between isoflavone intake and age, sex, ethnicity, economic status, body mass index, smoking status, alcohol consumption, and physical activity level (P values for interaction >0.05). Conclusions: We found that MetS prevalence decreased with increased isoflavone intake, suggesting that dietary patterns of soy food or supplement consumption may be a valuable strategy to reduce the disease burden and the prevalence of MetS.

The Influence of Dietary Interventions on Arterial Stiffness in Overweight and Obese Subjects

Arterial stiffness is often increased in overweight/obese subjects before the development of hypertension. It is also one of the earliest indicators of increased cardiovascular disease risk and can be considered a good predictor of the development of subclinical cardiovascular dysfunction. Arterial stiffness is a significant prognostic factor influencing cardiovascular risk, which dietary habits can modify. Obese patients should use the caloric-restricted diet because it augments aortic distensibility, diminishes pulse wave velocity (PWV), and increases the activity of endothelial nitric oxide synthases. High intake of saturated fatty acids (SFA), trans fats, and cholesterol, typical for the Western diet, impairs endothelial function and raises brachial-ankle PMV. The replacement of SFA with monounsaturated (MUFA) or polyunsaturated fatty acids (PUFA) derived from seafood and plants diminishes the risk of arterial stiffness. The dairy product intake (excluding butter) decreases PWV in the general population. The high-sucrose diet causes toxic hyperglycemia and increases arterial stiffness. Complex carbohydrates with a low glycemic index (including isomaltose) should be recommended to keep vascular health. The high sodium intake (>10 g/day), particularly associated with low potassium consumption, has a deleterious effect on arterial stiffness (↑ baPWV). Since vegetables and fruits are good sources of vitamins and phytochemicals, they should be recommended in patients with high PMV. Thus, the dietary recommendation to prevent arterial stiffness should be similar to the Mediterranean diet, which is rich in dairy products, plant oils, and fish, with a minimal red meat intake and five servings of fruits and vegetables daily.

Systematic review and meta-analysis of randomized, controlled trials on the effects of soy and soy products supplementation on serum adiponectin levels

BACKGROUND AND AIMS

Our aim in this meta-analysis was to determine the effect of soy and soy product supplementation on serum adiponectin levels.

METHOD

A systematic search was conducted using Medline (PubMed and Web of Science), Scopus, and Cochrane Library for eligible trials up to August 2020. A random-effects model was used to pool calculated effect sizes.

RESULTS

Seven trials were included in the overall analysis. Our analysis showed that soy and soy product supplementation did not significantly affect adiponectin concentrations (WMD = -0.77 μg/ml, 95% CI: -0.61, 2.15, P = 0.27) in comparison with a placebo. The between-study heterogeneity was high (I2: 68.2%, P = 0.004). Subgroup analysis, based on participants' health status and duration of the supplementation, could not detect the potential source of the observed heterogeneity. In addition, subgroup analysis showed that the effect was not statistically significant in all subgroups.

CONCLUSION

Overall, soy and soy product supplementation did not change the circulatory adiponectin levels. In addition, the results were not affected by the participant's health status and duration of supplementation. However, further studies are needed to confirm the present results.

Effects of a gluten-reduced or gluten-free diet for the primary prevention of cardiovascular disease

BACKGROUND

Cardiovascular diseases (CVD) are a major cause of disability and the leading cause of death worldwide. To reduce mortality and morbidity, prevention strategies such as following an optimal diet are crucial. In recent years, low-gluten and gluten-free diets have gained strong popularity in the general population. However, study results on the benefits of a gluten-reduced or gluten-free diet are conflicting, and it is unclear whether a gluten-reduced diet has an effect on the primary prevention of CVD.

OBJECTIVES

To determine the effects of a gluten-reduced or gluten-free diet for the primary prevention of CVD in the general population.

SEARCH METHODS

We systematically searched CENTRAL, MEDLINE, Embase, CINAHL and Web of Science up to June 2021 without language restrictions or restrictions regarding publication status. Additionally, we searched ClinicalTrials.gov for ongoing or unpublished trials and checked reference lists of included studies as well as relevant systematic reviews for additional studies.

SELECTION CRITERIA

We planned to include randomised controlled trials (RCTs) and non-randomised studies of interventions (NRSIs), such as prospective cohort studies, comparing a low-gluten or gluten-free diet or providing advice to decrease gluten consumption with no intervention, diet as usual, or a reference gluten-intake category. The population of interest comprised adults from the general population, including those at increased risk for CVD (primary prevention). We excluded cluster-RCTs, case-control studies, studies focusing on participants with a previous myocardial infarction and/or stroke, participants who have undergone a revascularisation procedure as well as participants with angina or angiographically-defined coronary heart disease, with a confirmed diagnosis of coeliac disease or with type 1 diabetes.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed eligibility of studies in a two-step procedure following Cochrane methods. Risk of bias (RoB) was assessed using the Cochrane risk of bias tool (RoB2) and the 'Risk Of Bias In Non-randomised Studies - of Interventions' (ROBINS-I) tool, and the certainty of evidence was rated using the GRADE approach.

MAIN RESULTS

One RCT and three NRSIs (with an observational design reporting data on four cohorts: Health Professionals Follow-up Study (HPFS), Nurses' Health Study (NHS-I), NHS-II, UK Biobank) met the inclusion criteria. The RCT was conducted in Italy (60 participants, mean age 41 ± 12.1 years), two NRSIs (three cohorts, HPFS, NHS-I, NHS II) were conducted across the USA (269,282 health professionals aged 24 to 75 years) and one NRSI (Biobank cohort) was conducted across the UK (159,265 participants aged 49 to 62 years). Two NRSIs reported that the lowest gluten intake ranged between 0.0 g/day and 3.4 g/day and the highest gluten intake between 6.2 g/day and 38.4 g/day. The NRSI reporting data from the UK Biobank referred to a median gluten intake of 8.5 g/day with an interquartile range from 5.1 g/day to 12.4 g/day without providing low- and high-intake categories. Cardiovascular mortality From a total of 269,282 participants, 3364 (1.3%) died due to cardiovascular events during 26 years of follow-up. Low-certainty evidence may show no association between gluten intake and cardiovascular mortality (adjusted hazard ratio (HR) for low- versus high-gluten intake 1.00, 95% confidence interval (CI) 0.95 to 1.06; 2 NRSIs (3 cohorts)). All-cause mortality From a total of 159,265 participants, 6259 (3.9%) died during 11.1 years of follow-up. Very low-certainty evidence suggested that it is unclear whether gluten intake is associated with all-cause mortality (adjusted HR for low vs high gluten intake 1.00, 95% CI 0.99 to 1.01; 1 NRSI (1 cohort)). Myocardial infarction  From a total of 110,017 participants, 4243 (3.9%) participants developed non-fatal myocardial infarction within 26 years. Low-certainty evidence suggested that gluten intake may not be associated with the development of non-fatal myocardial infarction (adjusted HR for low versus high gluten intake 0.99, 95% CI 0.89 to 1.10; 1 NRSI (2 cohorts)). Lowering gluten intake by 5 g/day also showed no association on the primary prevention of non-fatal and fatal myocardial infarction (composite endpoint) in linear dose-response meta-analyses (adjusted HR 1.02, 95% CI 0.98 to 1.06; 1 NRSI (2 cohorts)). Coronary risk factors  Type 2 diabetes From a total of 202,114 participants, 15,947 (8.0%) developed type 2 diabetes after a follow-up between 22 and 28 years. There was low-certainty evidence that a lower compared with a higher gluten intake may be associated with a slightly increased risk to develop type 2 diabetes (adjusted HR 1.14, 95% CI 1.07 to 1.22; 1 NRSI (3 cohorts)). Furthermore, lowering gluten intake by 5 g/day may be associated with a slightly increased risk to develop type 2 diabetes in linear dose-response meta-analyses (adjusted HR 1.12, 95% CI 1.08 to 1.16; 1 NRSI (3 cohorts)). Blood pressure, low-density lipoprotein level, body mass index (BMI) After six months of follow-up, very low-certainty evidence suggested that it is unclear whether gluten intake affects systolic blood pressure (mean difference (MD) -6.9, 95% CI -17.1 to 3.3 mmHg). There was also no difference between the interventions for diastolic blood pressure (MD -0.8, 95% CI -5.9 to 4.3 mmHg), low-density lipoprotein levels (MD -0.1, 95% CI -0.5 to 0.3 mmol/L) and BMI (MD -0.1, 95% CI -3.3 to 3.1 kg/m²).  No study reported data on adverse events or on other outcomes. Funding sources did not appear to have distorted the results in any of the studies.

AUTHORS' CONCLUSIONS

Very low-certainty evidence suggested that it is unclear whether gluten intake is associated with all-cause mortality. Our findings also indicate that low-certainty evidence may show little or no association between gluten intake and cardiovascular mortality and non-fatal myocardial infarction. Low-certainty evidence suggested that a lower compared with a higher gluten intake may be associated with a slightly increased risk to develop type 2 diabetes - a major cardiovascular risk factor. For other cardiovascular risk factors it is unclear whether there is a difference between a gluten-free and normal diet. Given the limited findings from this review predominantly based on observational studies, no recommendations for practice can be made.

Soy Food Intake Associated with Obesity and Hypertension in Children and Adolescents in Guangzhou, Southern China

The associations between soy food intake and cardio-metabolic risk factors in children remain unclear due to limited evidence. We aim to explore soy food intake and its association with the risks of obesity and hypertension in Chinese children and adolescents. A total of 10,536 children and adolescents aged 7–18 years (5125 boys and 5411 girls) were enrolled in a cross-sectional study in Guangzhou City, southern China. Data on demographic characteristics and dietary consumption were collected using self-reported questionnaires, and anthropometric characteristics were measured. Obesity, abdominal obesity, and hypertension were defined using Chinese criteria for children and adolescents. A multiple logistic regression model was applied to estimate the association between soy food intake and obesity and hypertension. Roughly 39.5% of the participants consumed soy food more than three times per week. The mean amounts of liquid and solid soy food intake were 0.35 ± 0.54 cups/day and 0.46 ± 0.63 servings/day, respectively. The adjusted odds ratios (OR) of hypertension among those with high liquid soy food intake and a high frequency of all soy food intake (more than three times/week) were 0.79 (95% confidence interval (CI), 0.67–0.94), and 0.83 (95% CI, 0.70–0.97) compared to those with no intake. Additionally, the adjusted OR of obesity among those with high solid soy food intake and a high frequency of all soy food intake were 1.34 (95% CI, 1.09–1.63) and 1.30 (95% CI, 1.07–1.58), respectively. In conclusion, 39.5% of southern Chinese children and adolescents had high soy food intake (more than three times/week), which was significantly associated with a lower prevalence of hypertension and a greater prevalence of obesity.

Impact of functional foods and nutraceuticals on high blood pressure with a special focus on meta-analysis: review from a public health perspective

In recent times many researchers are expressing immense interest in nutraceuticals and functional foods for combating various diseases or abnormal conditions, especially against hypertension (HT). Persistent HT is medically referred to as chronic high blood pressure (BP) and considered to be one of the major risk factors for the deadliest diseases including cardiovascular disease (CVD) and cerebrovascular diseases. Hence HT poses a serious socio-economic burden worldwide, particularly to developing countries. The current treatment strategy for HT includes standard anti-hypertensive drugs, which are associated with many adverse effects and lower drug adherence rates. Therefore, an alternative or complementary natural therapy (functional foods or nutraceuticals or dietary supplements) would be the alternate choice along with a modified lifestyle pattern that might help to manage or combat HT and its related complications. During this review, the author would like to shed light on the basic science behind HT including pathophysiology and the impact of dietary salt on HT and the impact of various functional foods or nutraceuticals against HT in humans (meta-analysis and systemic review). This contribution gives a better idea (public health perspective) for choosing the best functional foods/nutraceuticals for the prevention, management or delaying the onset of HT and its associated conditions along with modified lifestyle patterns and standard anti-hypertensive drugs.

Soy protein supplementation in men following radical prostatectomy: a 2-year randomized, placebo-controlled clinical trial

BACKGROUND

Many studies have addressed effects of dietary supplementation with soy protein, but most have been inconsistent and few have been long-term studies in men.

OBJECTIVES

This study was a secondary analysis of body weight, blood pressure, thyroid hormones, iron status, and clinical chemistry in a 2-y trial of soy protein supplementation in middle-aged to older men.

METHODS

Data were analyzed as secondary outcomes of a randomized controlled trial of dietary supplementation with 20 g/d soy protein isolate, providing 41 mg/d total isoflavones and 23 mg/d genistein, in 44- to 75-y-old men who were at risk of cancer recurrence following prostatectomy randomized to soy (n = 50) or a casein-based placebo (n  = 43). Weight, blood pressure, and blood samples were collected at baseline, every 2 mo in year 1, and every 3 mo in year 2.

RESULTS

Compared with casein, soy supplementation did not affect body weight, blood pressure, serum total cholesterol, calcium, phosphorus, and thyroid hormones. Serum ferritin concentrations doubled over 2 y in both groups (117-129%), whereas hemoglobin and hematocrit increased slightly. In an exploratory subgroup analysis of soy group data, weight increased in subjects producing equol but not in nonproducers. Blood pressure was reduced in nonequol producers but not in producers. Other endpoints were not affected by equol production status.

CONCLUSIONS

Soy protein supplementation for 2 y compared with a casein-based placebo did not affect body weight, blood pressure, serum total cholesterol, iron status parameters, calcium, phosphorus, and thyroid hormones. Exploratory analysis suggests that equol production status of subjects on soy may modify effects of soy on body weight and possibly blood pressure. This trial was registered at clinicaltrials.gov as NCT00765479.

The impact of type of dietary protein, animal versus vegetable, in modifying cardiometabolic risk factors: A position paper from the International Lipid Expert Panel (ILEP)

Proteins play a crucial role in metabolism, in maintaining fluid and acid-base balance and antibody synthesis. Dietary proteins are important nutrients and are classified into: 1) animal proteins (meat, fish, poultry, eggs and dairy), and, 2) plant proteins (legumes, nuts and soy). Dietary modification is one of the most important lifestyle changes that has been shown to significantly decrease the risk of cardiovascular (CV) disease (CVD) by attenuating related risk factors. The CVD burden is reduced by optimum diet through replacement of unprocessed meat with low saturated fat, animal proteins and plant proteins. In view of the available evidence, it has become acceptable to emphasize the role of optimum nutrition to maintain arterial and CV health. Such healthy diets are thought to increase satiety, facilitate weight loss, and improve CV risk. Different studies have compared the benefits of omnivorous and vegetarian diets. Animal protein related risk has been suggested to be greater with red or processed meat over and above poultry, fish and nuts, which carry a lower risk for CVD. In contrast, others have shown no association of red meat intake with CVD. The aim of this expert opinion recommendation was to elucidate the different impact of animal vs vegetable protein on modifying cardiometabolic risk factors. Many observational and interventional studies confirmed that increasing protein intake, especially plant-based proteins and certain animal-based proteins (poultry, fish, unprocessed red meat low in saturated fats and low-fat dairy products) have a positive effect in modifying cardiometabolic risk factors. Red meat intake correlates with increased CVD risk, mainly because of its non-protein ingredients (saturated fats). However, the way red meat is cooked and preserved matters. Thus, it is recommended to substitute red meat with poultry or fish in order to lower CVD risk. Specific amino acids have favourable results in modifying major risk factors for CVD, such as hypertension. Apart from meat, other animal-source proteins, like those found in dairy products (especially whey protein) are inversely correlated to hypertension, obesity and insulin resistance.

NutriGenomeDB: a nutrigenomics exploratory and analytical platform

Habitual consumption of certain foods has shown beneficial and protective effects against multiple chronic diseases. However, it is not clear by which molecular mechanisms they may exert their beneficial effects. Multiple -omic experiments available in public databases have generated gene expression data following the treatment of human cells with different food nutrients and bioactive compounds. Exploration of such data in an integrative manner offers excellent possibilities for gaining insights into the molecular effects of food compounds and bioactive molecules at the cellular level. Here we present NutriGenomeDB, a web-based application that hosts manually curated gene sets defined from gene expression signatures, after differential expression analysis of nutrigenomics experiments performed on human cells available in the Gene Expression Omnibus (GEO) repository. Through its web interface, users can explore gene expression data with interactive visualizations. In addition, external gene signatures can be connected with nutrigenomics gene sets using a gene pattern-matching algorithm. We further demonstrate how the application can capture the primary molecular mechanisms of a drug used to treat hypertension and thus connect its mode of action with hosted food compounds.

Carpinus turczaninowii Extract May Alleviate High Glucose-Induced Arterial Damage and Inflammation

Hyperglycemia-induced oxidative stress triggers severe vascular damage and induces an inflammatory vascular state, and is, therefore, one of the main causes of atherosclerosis. Recently, interest in the natural compound Carpinus turczaninowii has increased because of its reported antioxidant and anti-inflammatory properties. We investigated whether a C. turczaninowii extract was capable of attenuating high glucose-induced inflammation and arterial damage using human aortic vascular smooth muscle cells (hASMCs). mRNA expression levels of proinflammatory response [interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α)], endoplasmic reticulum (ER) stress [CCAAT-enhancer-binding proteins (C/EBP) homologous protein (CHOP)], and adenosine monophosphate (AMP)-protein activated kinase α2 (AMPK α2)], and DNA damage [phosphorylated H2.AX (p-H2.AX)] were measured in hASMCs treated with the C. turczaninowii extracts (1 and 10 μg/mL) after being stimulated by high glucose (25 mM) or not. The C. turczaninowii extract attenuated the increased mRNA expression of IL-6, TNF-α, and CHOP in hASMCs under high glucose conditions. The expression levels of p-H2.AX and AMPK α2 induced by high glucose were also significantly decreased in response to treatment with the C. turczaninowii extract. In addition, 15 types of phenolic compounds including quercetin, myricitrin, and ellagic acid, which exhibit antioxidant and anti-inflammatory properties, were identified in the C. turczaninowii extract through ultra-performance liquid chromatography-quadrupole-time of flight (UPLC-Q-TOF) mass spectrometry. In conclusion, C. turczaninowii may alleviate high glucose-induced inflammation and arterial damage in hASMCs, and may have potential in the treatment of hyperglycemia-induced atherosclerosis.

Sex differences in mechanisms of arterial stiffness

Arterial stiffness progressively increases with aging and is an independent predictor of cardiovascular disease (CVD) risk. Evidence supports that there are sex differences in the time course of aging-related arterial stiffness and the associated CVD risk, which increases disproportionately in postmenopausal women. The association between arterial stiffness and mortality is almost twofold higher in women versus men. The differential clinical characteristics of the development of arterial stiffness between men and women indicate the involvement of sex-specific mechanisms. This review summarizes the current literature on sex differences in vascular stiffness induced by aging, obesity, hypertension, and sex-specific risk factors as well as the impact of hormonal status, diet, and exercise on vascular stiffness in males and females. An understanding of the mechanisms driving sex differences in vascular stiffness has the potential to identify novel sex-specific therapies to lessen CVD risk, the leading cause of death in males and females. LINKED ARTICLES: This article is part of a themed section on The Importance of Sex Differences in Pharmacology Research. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v176.21/issuetoc.

Isoflavones

Phytoestrogens are naturally occurring nonsteroidal phenolic plant compounds that, due to their molecular structure and size, resemble vertebrate steroids estrogens. This review is focused on plant flavonoids isoflavones, which are ranked among the most estrogenic compounds. The main dietary sources of isoflavones for humans are soybean and soybean products, which contain mainly daidzein and genistein. When they are consumed, they exert estrogenic and/or antiestrogenic effects. Isoflavones are considered chemoprotective and can be used as an alternative therapy for a wide range of hormonal disorders, including several cancer types, namely breast cancer and prostate cancer, cardiovascular diseases, osteoporosis, or menopausal symptoms. On the other hand, isoflavones may also be considered endocrine disruptors with possible negative influences on the state of health in a certain part of the population or on the environment. This review deals with isoflavone classification, structure, and occurrence, with their metabolism, biological, and health effects in humans and animals, and with their utilization and potential risks.

Effects of isoflavone-containing soya protein on ex vivo cholesterol efflux, vascular function and blood markers of CVD risk in adults with moderately elevated blood pressure: a dose-response randomised controlled trial

Emerging CVD risk factors (e.g. HDL function and central haemodynamics) may account for residual CVD risk experienced by individuals who meet LDL-cholesterol and blood pressure (BP) targets. Recent evidence suggests that these emerging risk factors can be modified by polyphenol-rich interventions such as soya, but additional research is needed. This study was designed to investigate the effects of an isoflavone-containing soya protein isolate (delivering 25 and 50 g/d soya protein) on HDL function (i.e. ex vivo cholesterol efflux), macrovascular function and blood markers of CVD risk. Middle-aged adults (n 20; mean age=51·6 (sem 6·6) years) with moderately elevated brachial BP (mean systolic BP=129 (sem 9) mmHg; mean diastolic BP=82·5 (sem 8·4) mmHg) consumed 0 (control), 25 and 50 g/d soya protein in a randomised cross-over design. Soya and control powders were consumed for 6 weeks each with a 2-week compliance break between treatment periods. Blood samples and vascular function measures were obtained at baseline and following each supplementation period. Supplementation with 50 g/d soya protein significantly reduced brachial diastolic BP (-2·3 mmHg) compared with 25 g/d soya protein (Tukey-adjusted P=0·03) but not the control. Soya supplementation did not improve ex vivo cholesterol efflux, macrovascular function or other blood markers of CVD risk compared with the carbohydrate-matched control. Additional research is needed to clarify whether effects on these CVD risk factors depend on the relative health of participants and/or equol producing capacity.

Hypotensive effects of genistein: From chemistry to medicine

Genistein (4', 5, 7-trihydroxyisoflavone), a naturally occurring flavonoid characteristic of Leguminoseae plants, is a phyto-oestrogen exerting oestrogenic activity as both an agonist and an antagonist substance. A large body of evidence suggests that genistein possesses many physiological and pharmacological properties that make this molecule a potential agent for the prevention and treatment of a number of chronic diseases. Growing evidence suggests that genistein could act as a vasodilating, anti-thrombotic, and anti-atherosclerotic agent, exerting these effects through different mechanisms of action. This paper aims to review data from the literature assessing the beneficial effects of genistein on hypertension, one of the most important cardiovascular disease risk factors along with hyperglycemia and hyperlidipemia. In addition, we discuss the chemistry, main sources and bioavailability of genistein. Scientific findings support genistein's potential as a promising anti-hypertensive agent in different experimental models. However, clinical trials are very limited and more research will be required before genistein intake can be recommended as part of therapies targeting raised blood pressure.

Effect of soybean protein on blood pressure in postmenopausal women: a meta-analysis of randomized controlled trials

Soy protein intakes ≥25 g d⁻¹significantly decreased SBP and DBP, which may be due to the isoflavones component.

Targeting vascular (endothelial) dysfunction

Cardiovascular diseases are major contributors to global deaths and disability-adjusted life years, with hypertension a significant risk factor for all causes of death. The endothelium that lines the inner wall of the vasculature regulates essential haemostatic functions, such as vascular tone, circulation of blood cells, inflammation and platelet activity. Endothelial dysfunction is an early predictor of atherosclerosis and future cardiovascular events. We review the prognostic value of obtaining measurements of endothelial function, the clinical techniques for its determination, the mechanisms leading to endothelial dysfunction and the therapeutic treatment of endothelial dysfunction. Since vascular oxidative stress and inflammation are major determinants of endothelial function, we have also addressed current antioxidant and anti-inflammatory therapies. In the light of recent data that dispute the prognostic value of endothelial function in healthy human cohorts, we also discuss alternative diagnostic parameters such as vascular stiffness index and intima/media thickness ratio. We also suggest that assessing vascular function, including that of smooth muscle and even perivascular adipose tissue, may be an appropriate parameter for clinical investigations.

LINKED ARTICLES

This article is part of a themed section on Redox Biology and Oxidative Stress in Health and Disease. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.12/issuetoc.

A Systematic Review of the Efficacy of Bioactive Compounds in Cardiovascular Disease: Phenolic Compounds

The prevalence of cardiovascular diseases (CVD) is rising and is the prime cause of death in all developed countries. Bioactive compounds (BAC) can have a role in CVD prevention and treatment. The aim of this work was to examine the scientific evidence supporting phenolic BAC efficacy in CVD prevention and treatment by a systematic review. Databases utilized were Medline, LILACS and EMBASE, and all randomized controlled trials (RCTs) with prospective, parallel or crossover designs in humans in which the effects of BAC were compared with that of placebo/control were included. Vascular homeostasis, blood pressure, endothelial function, oxidative stress and inflammatory biomarkers were considered as primary outcomes. Cohort, ecological or case-control studies were not included. We selected 72 articles and verified their quality based on the Scottish Intercollegiate Guidelines Network, establishing diverse quality levels of scientific evidence according to two features: the design and bias risk of a study. Moreover, a grade of recommendation was included, depending on evidence strength of antecedents. Evidence shows that certain polyphenols, such as flavonols can be helpful in decreasing CVD risk factors. However, further rigorous evidence is necessary to support the BAC effect on CVD prevention and treatment.

A select review reporting the quality of studies measuring endothelial dysfunction in randomised diet intervention trials

A quality assessment of the primary studies reported in the literature carried out using select dietary ingredients (DI) purported to affect vascular endothelial function was conducted through a systematic PubMed search from January 2000 to August 2012. A total of seventy randomised controlled trials with defined DI (folic acid (fifteen), n-3 fatty acids (twenty), cocoa (fifteen) and isoflavones (twenty)) and standardised measures of vascular endothelial function were evaluated. Jadad scores, quality scoring parameters for DI and flow-mediated dilation (FMD) methodology used were ascertained. A total of 3959 randomised subjects, mean age 51 (se 0·21) years (range 9-79 years), were represented in the dataset. The mean Jadad scores did not differ statistically among the DI studies, with the majority of the studies being of good quality. Higher DI quality scores were achieved by studies using the botanical ingredients cocoa and isoflavones than by those using the nutrient ingredients folic acid and n-3 fatty acids. The mean DI quality scores were 4·13 (se 0·34), 5·20 (se 0·47), 6·13 (se 0·41) and 6·00 (se 0·59) for the folic acid, n-3 fatty acid, cocoa and isoflavone intervention studies, respectively (and significantly different). The mean Corretti FMD scores were 7·27 (se 0·56), 7·46 (se 0·79), 6·29 (se 0·61) and 7·11 (se 0·56) for the folic acid, n-3 fatty acid, cocoa and isoflavone intervention studies, respectively (NS). FMD studies failed to adequately describe the equipment used and more than half failed to provide an adequate description of the procedures used for vascular image acquisition and measurement. DI can be utilised for dietary intervention studies; however, the methodology should be clearly reported using the guidelines for assessment for both DI and FMD.

Flavonoids and arterial stiffness: promising perspectives

BACKGROUND AND AIMS

Flavonoids are a group of polyphenol compounds, ubiquitously found in plants. Great emphasis has been given to their possible benefits for cardiovascular health. These beneficial effects may be mediated by a specific action on arterial walls. Arterial stiffness is a marker of vascular aging, increasingly used in the clinical setting and assessed by pulse wave velocity. It has shown to be a robust predictor of cardiovascular events and mortality. This review aims at providing a comprehensive evaluation of available intervention and observational studies examining the relationship between flavonoid consumption and arterial stiffness.

DATA SYNTHESIS

A Medline(®) literature search was performed using the keywords "arterial stiffness" and "flavonoids". As a result, 2 cross-sectional and 16 intervention studies assessing the relationship between flavonoids intake and arterial stiffness were retained. Four intervention trials reported a significant decrease of arterial stiffness after a flavonoid-based intervention, independently from blood pressure changes. The two observational studies reported significant associations between a higher flavonoid consumption and a lower arterial stiffness. In this review, isoflavones, anthocyanins and to a lesser extent cocoa flavan-3-ols appeared to be the more efficient to improve vascular function.

CONCLUSIONS

Despite their heterogeneity, preliminary data seem to support an improvement of the arterial stiffness related to flavonoid intake. However, further research on absorption and dose-response effects of the specific flavonoid subclasses on arterial structure is warranted.

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.

The role of nutrition and nutraceutical supplements in the treatment of hypertension

Vascular biology, endothelial and vascular smooth muscle and cardiac dysfunction play a primary role in the initiation and perpetuation of hypertension, cardiovascular disease and target organ damage. Nutrient-gene interactions and epigenetics are predominant factors in promoting beneficial or detrimental effects in cardiovascular health and hypertension. Macronutrients and micronutrients can prevent, control and treat hypertension through numerous mechanisms related to vascular biology. Oxidative stress, inflammation and autoimmune dysfunction initiate and propagate hypertension and cardiovascular disease. There is a role for the selected use of single and component nutraceutical supplements, vitamins, antioxidants and minerals in the treatment of hypertension based on scientifically controlled studies which complement optimal nutrition, coupled with other lifestyle modifications.

Urinary isoflavonoids and risk of coronary heart disease

BACKGROUND

Whether soy food consumption may protect against coronary heart disease (CHD) remains controversial. No previous study has used biomarkers of soy intake in assessing the relationship between soy consumption and CHD. Biomarkers that reflect both intake and metabolism may be more informative than self-reports of dietary intake.

METHODS

We examined associations of urinary isoflavonoids, a biomarker of soy or soy isoflavone intake, with risk of CHD in a case-control study nested within two prospective cohort studies of Chinese adults in Shanghai. Cases were defined as subjects with no history of CHD at baseline who developed incident CHD during follow-up. Control subjects were randomly selected from those who remained free of CHD and matched to cases by sex, age, date and time of sample collection and antibiotic use. Baseline urinary isoflavonoids (daidzein, genistein, glycitein, equol, O-desmethylangolensin, dihydrodaidzein and dihydrogenistein) were compared between cases (n = 377) and control subjects (n = 753). Conditional logistic regression was used to evaluate the associations.

RESULTS

Total urinary isoflavonoids were not associated with CHD in either women or men. However, urinary equol excretion showed a significant inverse association with CHD in women. The adjusted odds ratios (95% confidence intervals) for CHD across increasing quartiles of equol levels in women were 1 (reference), 0.61 (0.32, 1.15), 0.51 (0.26, 0.98) and 0.46 (0.24, 0.89) (P = 0.02 for trend).

CONCLUSIONS

Our study suggests for the first time that equol, a bioactive metabolite of soy isoflavone daidzein, may be inversely associated with risk of CHD in women.

Dietary protein intake and blood pressure: a meta-analysis of randomized controlled trials

The authors conducted a meta-analysis of randomized controlled trials to evaluate the association of dietary protein intake with blood pressure. To identify articles published before April 2011, the authors searched electronic databases, conducted a manual bibliography review, and consulted experts in the field. Forty trials (including 3,277 participants in total) met the eligibility criteria and were included. Using a standardized form, 2 investigators independently abstracted data on study design, participant characteristics, and treatment outcomes. Net change estimates were pooled across trials using random-effects models. Compared with carbohydrate, dietary protein intake was associated with significant changes in mean systolic and diastolic blood pressure of -1.76 mm Hg (95% confidence interval (CI): -2.33, -1.20) and -1.15 mm Hg (95% CI: -1.59, -0.71), respectively (both P 's < 0.001). Both vegetable protein and animal protein were associated with significant blood pressure changes of -2.27 mm Hg (95% CI: -3.36, -1.18) and -2.54 mm Hg (95% CI: -3.55, -1.53), respectively, for systolic blood pressure (both P 's < 0.001) and -1.26 mm Hg (95% CI: -2.26, -0.26) and -0.95 mm Hg (95% CI: -1.72, -0.19), respectively, for diastolic blood pressure (both P 's = 0.014). Blood pressure reduction was not significantly different when vegetable protein was compared directly with animal protein. These findings indicate that partially replacing dietary carbohydrate with protein may be important for the prevention and treatment of hypertension.

Antihypertensive effects of dietary protein and its mechanism

Hypertension is a leading cause of morbidity and mortality worldwide. Individuals with hypertension are at increased risk of stroke, heart disease and kidney failure. Both genetic and lifestyle factors, particularly diet, have been attributed an important role in the development of hypertension. Reducing dietary sugar and salt intake can help lower blood pressure; similarly, adequate protein intake may also attenuate hypertension. Observational, cross-sectional and longitudinal epidemiological studies, and controlled clinical trials, have documented significant inverse associations between protein intake and blood pressure. Human and animal studies have shown that specific amino acids within proteins may have antihypertensive effects. Cysteine, glutathione (a tripeptide), glutamate and arginine attenuate and prevent alterations that cause hypertension including insulin resistance, decreased nitric oxide bioavailability, altered renin angiotensin system function, increased oxidative stress and formation of advanced glycation end products. Leucine increases protein synthesis in skeletal muscle and improves insulin resistance by modulating hepatic gluconeogenesis. Taurine and tryptophan attenuate sympathetic nervous system activity. Soy protein helps lower blood pressure through its high arginine content and antioxidant activity exhibited by isoflavones. A diet containing an ample amount of protein may be a beneficial lifestyle choice for individuals with hypertension; one example is the Dietary Approaches to Stop Hypertension (DASH) diet, which is low in salt and saturated fat; includes whole grains, lean meat, poultry, fish and nuts; and is rich in vegetables, fruits and low-fat dairy products, which are good sources of antioxidant vitamins, minerals and fibre. Including an adequate supply of soy in the diet should also be encouraged.

Dietary genistein induces sex-dependent effects on murine body weight, serum profiles, and vascular function of thoracic aortae

BACKGROUND

The influence on, or interaction of, sex and dietary genistein on serum markers of cardiovascular health and cardiovascular function remain unclear.

OBJECTIVES

Our purpose was to examine the effects of a genistein-containing diet (600 mg/kg food) (600G) and a genistein-free diet (0G), on cardiovascular risk parameters of male and female mice.

METHODS

C57BL/6J mice were fed the diets for 1 month, after which time blood pressure, serum markers, and in vitro vascular reactivity was measured.

RESULTS

Males fed the 600G diet gained significantly less weight than males fed the 0G diet (by 1.71 g); diet had no effect on female weight gain. Males fed the 600G diet also exhibited significantly elevated serum insulin (2.9 [0.5] vs 1.8 [0.4] ng/dL), and decreased serum glucose (0.15 [0.01] vs 0.24 [0.02] ng/dL) levels, resulting in a significant increase in the ratio of insulin to glucose; insulin and glucose levels were not changed by dietary genistein in females. Arterial pressure measurements from 0G-fed males were lower than other groups. However, basal vascular reactivity of isolated aortic rings was significantly increased by the 600G diet in both males (from 0.55 [0.03] to 0.94 [0.18] g) and females (from 0.45 [0.04] to 0.78 [0.09] g). Aortic wall thickness was not affected by diet. Norepinephrine-mediated contractility was also greater in aortic rings of male and female mice fed the 600G diet, and differences from the 0G diet persisted in the presence of L-NG-nitroarginine methyl ester but were completely accounted for by increased basal reactivity.

CONCLUSION

Our data indicate that 1 month of a 600G or 0G diet significantly alters vascular function independent of sex. In contrast, sex-dependent differences exist in well-established serum markers of cardiovascular health and disease.

Effect of soy isoflavones on blood pressure: a meta-analysis of randomized controlled trials

BACKGROUND AND AIM

The effect of soy isoflavones on blood pressure is controversial. The objective of this study was to evaluate the effect of dietary soy isoflavones on blood pressure.

METHODS AND RESULTS

Trials were searched in PubMed, the Cochrane Library, Embase and references cited in related reviews and studies. A total of eleven trials were reviewed. Meta-analysis results showed a mean decrease of 2.5 mm Hg (95% CIs, - 5.35 to 0.34 mm Hg; P = 0.08) for systolic blood pressure and 1.5 mm Hg (95% CIs, - 3.09 to 0.17 mm Hg; P = 0.08) for diastolic blood pressure in the soy isoflavones-treated group compared to placebo. Meta-regression and subgroup analyses indicated that blood pressure status was a significant predictor of heterogeneity for the effect of soy isoflavones on blood pressure. Subgroup analysis of hypertensive subjects revealed that a greater blood pressure reduction was identified in the soy isoflavone-treated group compared to placebo (5 trials; SBP: - 5.94, 95% CIs [- 10.55, - 1.34] mm Hg, P = 0.01; DBP: - 3.35, 95% CIs [- 6.52, - 0.19] mm Hg, P = 0.04). In contrast, treatment with soy isoflavones did not lead to a significant reduction in blood pressure in normotensive subjects (6 trials; SBP: 0.29, 95% CIs [- 2.39, 2.97] mm Hg, P = 0.83; DBP: - 0.43, 95% CIs [- 1.66, 0.81] mm Hg, P = 0.50).

CONCLUSION

Soy isoflavones had an effect of lowering blood pressure in hypertensive subjects, but not in normotensive subjects. Larger trials need to be carried out to confirm the present findings.

Exposure to isoflavone-containing soy products and endothelial function: a Bayesian meta-analysis of randomized controlled trials

BACKGROUND AND AIMS

To determine whether and to what degree exposure to isoflavone-containing soy products affects EF. Endothelial dysfunction has been identified as an independent coronary heart disease risk factor and a strong predictor of long-term cardiovascular morbidity and mortality. Data on the effects of exposure to isoflavone-containing soy products on EF are conflicting.

METHODS AND RESULTS

A comprehensive literature search was conducted using the PUBMED database (National Library of Medicine, Bethesda, MD) inclusively through August 21, 2009 on RCTs using the keywords: soy, isoflavone, phytoestrogen, EF, flow mediated vasodilation, and FMD. A Bayesian meta-analysis was conducted to provide a comprehensive account of the effect of isoflavone-containing soy products on EF, as measured by FMD. A total of 17 RCTs were selected as having sufficient data for study inclusion. The overall mean absolute change in FMD (95% Bayesian CI) for isoflavone-containing soy product interventions was 1.15% (-0.52, 2.75). When the effects of separate interventions were considered, the treatment effect for isolated isoflavones was 1.98% (0.07, 3.97) compared to 0.72% (-1.39, 2.90) for isoflavone-containing soy protein. The models were not improved when considering study-specific effects such as cuff measurement location, prescribed dietary modification, and impaired baseline FMD.

CONCLUSIONS

Cumulative evidence from the RCTs included in this meta-analysis indicates that exposure to soy isoflavones can modestly, but significantly, improve EF as measured by FMD. Therefore, exposure to isoflavone supplements may beneficially influence vascular health.

Effect of soya protein on blood pressure: a meta-analysis of randomised controlled trials

Observational studies have indicated that soya food consumption is inversely associated with blood pressure (BP). Evidence from randomised controlled trials (RCT) on the BP-lowering effects of soya protein intake is inconclusive. We aimed to evaluate the effectiveness of soya protein intake in lowering BP. The PubMed database was searched for published RCT in the English language through to April 2010, which compared a soya protein diet with a control diet. We conducted a random-effects meta-analysis to examine the effects of soya protein on BP. Subgroup and meta-regression analyses were performed to explore possible explanations for heterogeneity among trials. Meta-analyses of twenty-seven RCT showed a mean decrease of 2·21 mmHg (95 % CI - 4·10, - 0·33; P = 0·021) for systolic BP (SBP) and 1·44 mmHg (95 % CI - 2·56, - 0·31; P = 0·012) for diastolic BP (DBP), comparing the participants in the soya protein group with those in the control group. Soya protein consumption significantly reduced SBP and DBP in both hypertensive and normotensive subjects, and the reductions were markedly greater in hypertensive subjects. Significant and greater BP reductions were also observed in trials using carbohydrate, but not milk products, as the control diet. Meta-regression analyses further revealed a significantly inverse association between pre-treatment BP and the level of BP reductions. In conclusion, soya protein intake, compared with a control diet, significantly reduces both SBP and DBP, but the BP reductions are related to pre-treatment BP levels of subjects and the type of control diet used as comparison.

Oxidative stress and endothelial dysfunction: therapeutic implications

In a previous issue of Annals of Medicine, we presented evidence in support of the concept that an abnormally increased production of reactive oxygen species plays a central role in the genesis and progression of cardiovascular disease. While a number of preclinical lines of evidence support this concept, and despite the results of many studies suggesting a beneficial impact of antioxidant drugs on endothelial function, large clinical trials have failed to demonstrate a benefit of antioxidants on cardiovascular outcomes. Studies exploring the possibility that classical antioxidants such as vitamin C, vitamin E, selenium, or folic acid may improve the prognosis of patients with cardiac disease have substantially reported neutral-and occasionally negative-results. In contrast, medications such as statins, ACE inhibitors, certain β-blockers, or angiotensin I receptor blockers, which possess indirect 'ancillary' antioxidant properties, have been associated with beneficial effects in both preclinical studies and large clinical trials. The reasons for the failure of the 'direct' approach to antioxidant therapy, and for the success of the therapy with these drugs, are discussed in the present review.

Soy-derived phytoestrogens as preventive and acute neuroprotectors in experimental ischemic stroke: influence of rat strain

The ability of a soy-based high-phytoestrogen diet (nutritional intervention) or genistein (pharmacological intervention), to limit ischemic brain damage in Wistar, Wistar-Kyoto (WKY) and spontaneously hypertensive (SHR) rats, has been assessed. As to the nutritional intervention, two groups from each strain received either a phytoestrogen-free (PE-0) or a high-phytoestrogen (PE-600) diet from weaning to adulthood. As to the pharmacological intervention, all animals were fed the standard soy-free AIN-93G diet and subsequently separated into two groups from each strain to receive either pure genistein (aglycone form, 1mg/kg/day intraperitoneal) or vehicle at 30 min reperfusion. After an episode of 90 min ischemia (intraluminal thread procedure) followed by 3 days reperfusion, cerebral infarct volume was measured. Arterial blood pressure (ABP) was significantly higher at the basal stage (just before ischemia) in SHR (140 ± 7 mmHg, n=17, p<0.05) than in Wistar (113 ± 4mmHg, n=23) and WKY (111 ± 6mmHg, n=14) rats. No significant differences were shown among the three stages (basal, ischemia, reperfusion) within each rat strain for both PE-0 and PE-600 diets. Wistar, but not WKY or SHR, rats fed the PE-600 diet showed significantly lower infarct volumes than their counterparts fed the PE-0 diet (30 ± 3% vs. 17 ± 3%, p<0.01). Genistein-treated Wistar, but not WKY or SHR, rats showed significantly lower infarct volumes than their vehicle-treated controls (27 ± 2% vs. 15 ± 2%, p<0.01). Our results demonstrate that: (1) the neuroprotective action of either chronic or acute exposure to soy isoflavones is strain-dependent, since it was shown in Wistar but not WKY or SHR rats; and (2) the soy-based diet does not prevent development of hypertension in SHR rats.

Genistein induces estrogen-like effects in ovariectomized rats but fails to increase cardiac GLUT4 and oxidative stress

This study aimed to determine whether a 2-week genistein treatment induced estrogen-like effects in ovariectomized (OVX) Sprague-Dawley rats, after 2 weeks of subcutaneous genistein injections (250 mg/kg of body weight/day). Uterine weight, uterine-to-body weight ratio, femur weight, and femur-to-body weight ratio were all significantly increased with genistein in OVX rats. Body weight was significantly decreased with genistein in OVX rats. Genistein had no effect on the weights of heart, heart-to-body ratio, and fat pad but significantly decreased heart rate and pulse pressure. Genistein had no effect on cardiac GLUT4 protein, oxidative stress, plasma glucose, nonesterified fatty acids, or low-density lipoprotein levels; however, plasma insulin levels were significantly increased. Our results show that a 2-week genistein treatment produced favorable estrogen-like effects on some physical and physiological characteristics in OVX rats. However, based on our experimental conditions, the effects of genistein were not associated with changes in cardiac GLUT4 or oxidative stress.

Cardiovascular friendly natural products: a promising approach in the management of CVD

Natural products play an important role as nutritional supplements and provide potential health benefits in cardiovascular diseases (CVD). Compiling data from experimental, epidemiological and clinical studies indicates that dietary nutrients have profound cardioprotective effects in the primary as well as secondary prevention of coronary heart disease, hence they are considered as cardiovascular friendly natural products. The mechanism of cardioprotection produced by dietary nutritional supplements such as flavonoids (citrus fruits, pulses, red wine, tea and cocoa), olive oil, omega-3 (omega-3) fatty acids (fish oil and fish-based products), lycopene (tomato and tomato-based products), resveratrol (grapes and red wine), coffee, and soy in the prevention and treatment of cardiovascular disorders have been discussed in the present review, with the emphasis of epidemiological and clinical studies. Based on the intriguing results of various studies, prophylactic and therapeutic potential of cardiovascular friendly natural products have been suggested. The supplementation of cardiovascular friendly natural products needs to be considered in all populations who have high prevalence of CVD.

Anti-hypertensive nutraceuticals and functional foods

Epidemiological studies have demonstrated that elevated blood pressure is one of the major risk factors for stroke and coronary heart disease (CHD). A close association between blood pressure and the incidence of cardiovascular diseases is well established if systolic/diastolic blood pressure is above 140/90 mmHg. In recent years, nutraceuticals and functional foods have attracted considerable interest as potential alternative therapies for treatment of hypertension, especially for prehypertensive patients, whose blood pressure is marginally or mildly high but not high enough to warrant the prescription of blood pressure-lowering medications. This review summarizes the findings of recent studies on the chemistry, production, application, efficacy, and mechanisms of popular blood pressure-lowering nutraceuticals and functional foods including the Dietary Approaches to Stop Hypertension (DASH) diet plan, L-arginine, chlorogenic acid, fermented milk, garlic, onion, tea, soybean, ginger, hawthorn, and fish oil.

Coronary vasomotor and blood flow responses to isoflavone-intact soya protein in subjects with coronary heart disease or risk factors for coronary heart disease

Results in animals suggest favourable coronary vasomotor actions of isoflavones; however, the effects of isoflavones on the human coronary circulation have not been determined. In the present study, we therefore investigated the effects of short-term isoflavone-intact soya protein ingestion on basal coronary arterial tone and stimulated vasoreactivity and blood flow in patients with CHD (coronary heart disease) or risk factors for CHD. Seventy-one subjects were randomized, double-blind, to isoflavone-intact soya protein [active; n=33, aged 58+/-8 years (mean+/-S.D.)] or isoflavone-free placebo (n=38, aged 61+/-8 years) for 5 days prior to coronary angiography. In 25 of these subjects, stimulated coronary blood flow was calculated from flow velocity, measured using intracoronary Doppler and coronary luminal diameter before and after intracoronary adenosine, ACh (acetylcholine) and ISDN (isosorbide dinitrate) infusions. Basal and stimulated coronary artery luminal diameters were measured using quantitative coronary angiography. Serum concentrations of the isoflavones genistein, daidzein and equol were increased by active treatment (P<0.001, P<0.001 and P=0.03 respectively). Basal mean luminal diameter was not significantly different between groups (active compared with placebo: 2.9+/-0.7 compared with 2.73+/-0.44 mm, P=0.31). There was no difference in luminal diameter, flow velocity and volume flow responses to adenosine, ACh or ISDN between groups. Active supplement had no effect on basal coronary artery tone or stimulated coronary vasoreactivity or blood flow compared with placebo. Our results suggest that short-term consumption of isoflavone-intact soya protein is neither harmful nor beneficial to the coronary circulation of humans with CHD or risk factors for CHD. These results are consistent with recent cautions placed on the purported health benefits of plant sterols.

Effects of botanical dietary supplements on cardiovascular, cognitive, and metabolic function in males and females

BACKGROUND

The onset of menopause marks a pivotal time in which the incidence of hypertension and of cardiovascular disease (CVD) begins to increase dramatically in women. Before menopause, the incidences of these diseases are significantly lower in women than in age-matched men. After menopause, the rates of these diseases in women eventually approximate those in men. The loss of endogenous estrogen at menopause has been traditionally believed to be the primary factor involved in these changes.

OBJECTIVE

This review summarizes recent findings regarding the effectiveness of botanicals in the treatment of some menopausal symptoms and other symptoms of aging (eg, rise in arterial pressure, cognitive decline, insulin resistance, and hyperlipidemia).

METHODS

Articles were selected for inclusion in this review based on the significance of the research and contribution to the current understanding of how each botanical elicits cardioprotective effects. To this end, PubMed and MEDLINE databases were searched, using terms that included the name of the specific botanical along with the relevant aspects of its action(s), such as blood pressure, glycemic control, and lipids. Most of the articles used were published within the past 5 years, although some older articles that were seminal in advancing the current understanding of botanicals were also included.

RESULTS

Soy has been found to lower plasma lipid concentrations and arterial pressure in postmenopausal women and age-matched men, and to have protective effects in heart disease and atherosclerosis of the carotid and coronary circulation. Soy was also found to lower fasting insulin concentrations and glycosylated hemoglobin concentrations. Grape seed extract, another frequently used botanical, contains polyphenols that have been found to reduce arterial pressure and salt-sensitive hypertension in estrogendepleted animal models.

CONCLUSION

Several botanical compounds have been found to have beneficial effects in the treatment of the symptoms of menopause and other symptoms of aging, including CVD, cognitive decline, and metabolic diseases.

Investigating the Optimal Soy Protein and Isoflavone Intakes for Women: A Perspective

Traditional soyfoods have been consumed for centuries throughout much of East Asia and, recently, these foods have also become popular in the West. Soyfoods and specific soybean components, such as the protein and isoflavones, have attracted attention for their possible health benefits. Isoflavones are classified as phytoestrogens and have been postulated to be natural alternatives to hormone therapy for menopausal women. To provide guidance on optimal soy intake, this article evaluates Asian soy consumption and both clinical and Asian epidemiologic studies that examined the relationship between soy intake and a variety of health outcomes. On the basis of these data and the standard principles of dietary practice the author suggests that optimal soy protein and isoflavone intakes are 15–20 g/day and 50–90 mg/day, respectively. In addition, an intake of 25 g/day soy protein can be specifically used as the recommendation for cholesterol reduction.

[Usefulness of phyto-oestrogens in reduction of blood pressure. Systematic review and meta-analysis]

OBJECTIVES

To determine whether treatment with phyto-oestrogens or soya protein succeeds in lowering blood pressure.

DESIGN

A systematic review, evaluating all the observation studies and clinical trials, was conducted, followed by a meta-analysis to evaluate blood pressure variations in patients treated with phyto-oestrogens. SEARCH: The search strategy adopted used the terms "phyto-oestrogens," "soya meals," "hypertension," and "blood pressure."

DATA SOURCES

The data bases MEDLINE, EMBASE, Cochrane, OVID were used, without time or language restrictions. References in the relevant articles were searched for manually.

STUDY SELECTION

Two independent reviewers analysed the studies found in the search.

DATA EXTRACTION

The Jadad scale was used for the clinical trials and the numerical data in the text or referred to in tables were extracted. Evaluation was made of which observational and experimental articles showed a drop in blood pressure with phyto-oestrogens and which did not. In the meta-analysis, data on sample size, difference in blood pressure before and after intervention and standard deviation were extracted from each study. The weighted difference of means was used with the model of randomised effects. The Review Manager v4.2.9 programme was used.

RESULTS

No significant variations in blood pressure were found, whether systolic (-1.20 mm Hg; 95% CI, -2.80 to 0.41 mm Hg) or diastolic (-1.31 mm Hg; 95% CI, -2.73 to 0.11). If there were any variations, they are clinically of little importance. There was also an important degree of both statistical and clinical heterogeneity.

CONCLUSIONS

There are no statistically significant or clinically important differences in blood pressure between patients treated with phyto-oestrogens and those not treated.

Are soy foods protective against ischemic stroke?

Ischemic stroke is one of the leading causes of mortality and morbidity in the world. A large number of studies have observed the beneficial effects of soy protein and soy polyunsaturated fat in lowering blood cholesterol, reducing blood pressure and improving cardiovascular health. This study aims to investigate the potential of a soy food diet in the prevention of ischemic stroke through evaluation of evidence from clinical trials, meta-analyses, experimental and epidemiological studies.