The effects of catechin on endothelial function: A systematic review and meta-analysis of randomized controlled trials

Plasma nitrate, dietary nitrate, blood pressure, and vascular health biomarkers: a GRADE-Assessed systematic review and dose-response meta-analysis of randomized controlled trials

BACKGROUND

Hypertension and vascular dysfunction are major health concerns, and studies have suggested different interventions, including dietary nitrate (NO3), to improve it. We sought to elucidate the effects of dietary NO3 on plasma NO3 and nitrite (NO2) levels and to determine the shape of the effect of dietary NO3 on blood pressure (BP) and vascular health biomarkers.

METHODS

PubMed, Scopus, and Web of Science were searched up to February 2024 for eligible randomized controlled trials (RCTs). The pooled results were reported as weighted mean differences (WMD) and 95% confidence intervals (CIs).

RESULTS

Our analysis of 75 RCTs involving 1823 participants revealed that per each millimole (mmol) increase in the administered NO3 dose, both acute (WMD: 32.7µmol/L; 95%CI: 26.1, 39.4) and chronic-term (WMD: 19.6µmol/L; 95%CI: 9.95, 29.3) plasma NO3 levels increased. Per each mmol increase in NO3 intake, a reduction in systolic BP levels was observed in the acute (WMD: -0.28mmHg; 95%CI: -0.40, -0.17), short-term (WMD: -0.24mmHg; 95%CI: -0.40, -0.07), and medium-term (WMD: -0.48mmHg; 95%CI: -0.71, -0.25) periods. Furthermore, a decrease in diastolic BP for each mmol increase in NO3 intake (WMD: -0.12 mmHg; 95% CI: -0.21, -0.03) was shown. Moreover, a linear dose-response relationship was indicated between each mmol of NO3 intake and medium-term pulse wave velocity (WMD: -0.07 m/s; 95%CI: -0.11, -0.03), medium-term flow-mediated dilation (WMD: 0.30%; 95%CI: 0.15, 0.46), and medium-term augmentation index (WMD: -0.57%; 95%CI: -0.98, -0.15).

CONCLUSION

We observed dose-dependent increases in plasma NO3 and NO2 levels, along with consequent reductions in BP and enhancements in vascular health following dietary NO3 supplementation. Future high-quality, population-specific studies with optimized dietary NO3 dosages are needed to strengthen the certainty of the evidence.

REGISTRATION

The protocol for this systematic review was registered in PROSPERO under the registration number CRD42024535335.

Plant Polyphenols as Heart's Best Friends: From Health Properties, to Cellular Effects, to Molecular Mechanisms of Action

Polyphenols are micronutrients found in fruits, vegetables, tea, coffee, cocoa, medicinal herbs, fish, crustaceans, and algae. They can also be synthesized using recombinant microorganisms. Interest in plant-derived natural compounds has grown due to their potential therapeutic effects with minimal side effects. This is particularly important as the aging population faces increasing rates of chronic diseases such as cancer, diabetes, arthritis, cardiovascular, and neurological disorders. Studies have highlighted polyphenols' capacity to reduce risk factors linked to the onset of chronic illnesses. This narrative review discusses polyphenol families and their metabolism, and the cardioprotective effects of polyphenols evidenced from in vitro studies, as well as from in vivo studies, on different animal models of cardiac disease. This study also explores the molecular mechanisms underlying these benefits. Current research suggests that polyphenols may protect against ischemia, hypertension, cardiac hypertrophy, heart failure, and myocardial injury through complex mechanisms, including epigenetic and genomic modulation. However, further studies under nutritionally and physiologically relevant conditions, using untargeted multigenomic approaches, are needed to more comprehensively elucidate these mechanisms and firmly prove the cardioprotective effects of polyphenols.

The Acute Ingestion of Yerba Mate (Ilex paraguariensis) Infusion Does Not Modify Endothelial Function, Hemodynamics, or Heart Rate Variability: A Randomized Crossover Clinical Trial

BACKGROUND AND AIMS

Herbal plants may contribute to reducing the incidence of cardiovascular disease. Yerba mate (YM) emerges as a candidate to improve endothelial function, hemodynamics, and heart rate variability (HRV) due to its antioxidant and anti-inflammatory properties, potentially decreasing cardiovascular risk. Therefore, studies are needed to assess the effect of YM ingestion on these parameters. This study aimed to evaluate the impact of acute ingestion of YM infusion (hot or cold) on endothelial function, hemodynamics, and HRV.

METHODS AND RESULTS

In this crossover randomized clinical trial, 13 participants (18-40 years old) of both genders were evaluated under three conditions: control (water), cold YM infusion, and hot YM infusion. The primary outcome was endothelial function assessed through flow-mediated dilation (FMD), with the secondary outcomes including blood pressure (BP), heart rate (HR) and HRV. Parameters were evaluated before and after intervention (40' and 80'). Analysis of variance (ANOVA) showed an intervention effect on FMD (%) (p < 0.05), with both cold and hot YM associated to higher FMD% compared to control, although no time or time*intervention effects were found. ANOVA also showed a time effect on BP, HR, and HRV time and frequency domains variables (p < 0.05), though no time*intervention or intervention effect was observed.

CONCLUSION

We did not find acute effects of YM infusion on endothelial function, central hemodynamic, or autonomic parameters in healthy adults. These results were not impacted by the temperature of YM. Further studies should assess the dose-response of acute and chronic YM ingestion on endothelial function.

TRIAL REGISTRATION

U1111-1289-9324, retrospectively registered in May 2023.

The Association between Food Groups, Nutraceuticals, and Food Supplements Consumption on Vascular Health Outcomes: A Literature Review

Vascular aging, marked by alterations in the structure and function of blood vessels, including heightened arterial stiffness and impaired endothelial function, is linked to a higher likelihood of developing cardiovascular and age-associated pathological conditions. Oxidative stress and inflammation are key stimulation factors in vascular aging. Engaging in healthy dietary habits could enhance the functioning of blood vessels. The aim of this study was to conduct a literature review of the evidence regarding the relationship between food regimens, nutraceuticals, and dietary supplements and vascular health. A search of electronic databases, including PubMed, Scopus, and Web of Science Core Collection, was performed. Experimental and observational studies evaluating the association between food groups, nutraceuticals, supplements, and endothelial function and/or arterial stiffness were deemed eligible for this narrative review. Based on the current body of the included studies, food groups, nutraceuticals, and dietary supplements may not demonstrate superiority over placebos in enhancing markers of vascular health. To obtain more reliable evidence on the effectiveness of interventions in vascular health, additional RCTs with larger sample sizes, extended follow-up periods, and multi-center participation are necessary. Enhancing the credibility of these RCTs requires better control of dietary variables and more precise measurement of vascular health markers.

Brazil nuts potential: effects on lipid peroxidation and heart health in nephrectomized rats

OBJECTIVES

To investigate the effects of a Brazil nut-enriched diet on the wall thickness and the left ventricular chamber diameter of the heart, and lipid peroxidation in a CKD-induced model.

METHODS

Male Wistar rats at 12 weeks of age were divided into two groups (n=16/group): the Nx group, which underwent 5/6 nephrectomy, and the Sham group, as a control. After 5 weeks, the groups were subdivided according to diet (n=8/group): the Nx and Sham groups received a control diet; the Nx5% and Sham5% groups received a diet enriched with 5 % Brazil nuts for 8 weeks. The left ventricular thickening and chamber diameter were determined. Plasma biochemical parameters were evaluated. Analysis of thiobarbituric acid reactive substances (TBARS) and antioxidant enzyme activity was performed in the plasma and the left ventricle (LV). LV mRNA expression of nuclear factor-kappa B (NF-κB) and nuclear factor erythroid 2-related factor 2 (Nrf2) was evaluated by reverse transcription-polymerase chain reaction.

RESULTS

The Nx5% group showed a remodeled LV wall with decreased thickness compared to the Nx group (p=0.016). Furthermore, LV TBARS concentration was reduced in the Nx5% group (p=0.0064). In addition, the Nx5% group showed an increase in plasma GPx activity (p=0.0431). No significant results were found concerning the LV mRNA expression of NF-κB and Nrf2 genes.

CONCLUSIONS

A Brazil nut-enriched diet decreased LV thickness and LV TBARS concentration and increased GPx activity in a 5/6 nephrectomy experimental model, making it a promising adjuvant therapy to improve antioxidant status and cardiovascular outcomes in chronic kidney disease.

The Interplay between Endogenous and Foodborne Pro-Oxidants and Antioxidants in Shaping Redox Homeostasis

Oxidative stress has been known about in biological sciences for several decades; however, the understanding of this concept has evolved greatly since its foundation. Over the past years, reactive oxygen species, once viewed as solely deleterious, have become recognized as intrinsic components of life. In contrast, antioxidants, initially believed to be cure-all remedies, have failed to prove their efficacy in clinical trials. Fortunately, research on the health-promoting properties of antioxidants has been ongoing. Subsequent years showed that the former assumption that all antioxidants acted similarly was greatly oversimplified. Redox-active compounds differ in their chemical structures, electrochemical properties, mechanisms of action, and bioavailability; therefore, their efficacy in protecting against oxidative stress also varies. In this review, we discuss the changing perception of oxidative stress and its sources, emphasizing everyday-life exposures, particularly those of dietary origin. Finally, we posit that a better understanding of the physicochemical properties and biological outcomes of antioxidants is crucial to fully utilize their beneficial impact on health.

Dietary polyphenols and sleep modulation: Current evidence and perspectives

Polyphenols are plant compounds with several biological activities. This review aims to summarize current knowledge on the potential role of polyphenols in modulating sleep. A total of 28 preclinical studies, 12 intervention studies and four observational studies exploring the role of polyphenol intake on sleep were identified. From animal studies, 26 out of the 28 studies found beneficial effects of polyphenols on sleep architecture. Three out of four human observational studies found a beneficial association between polyphenol intake and sleep parameters. And, among clinical intervention studies, eight from a total of 12 studies found some beneficial effect of polyphenol intake on various sleep parameters, although some discrepancies between studies were found. Overall, emerging evidence suggests a benefit of polyphenol intake on sleep. Several mechanisms of action have been suggested, ranging from effects on neurotransmitters to an action through the gut-brain axis. However, more research in this field is needed, emphasizing the use of nutritional doses in mechanistic studies and interventions targeting participants with sleep problems. This would allow to elucidate whether an additional biological effect of polyphenols is modulation of sleep, a behavior associated with adverse health outcomes.

The effects of folic acid supplementation on endothelial function in adults: a systematic review and dose-response meta-analysis of randomized controlled trials

BACKGROUND

Endothelial dysfunction serves as an early marker for the risk of cardiovascular disease (CVD); therefore, it is an attractive site of therapeutic interventions to reduce the risk of CVD. This study was conducted to investigate the effect of folic acid supplementation on endothelial function markers in randomized controlled trials (RCTs).

METHODS

PubMed, ISI web of science, and Scopus databases were searched up to July 2022 for detecting eligible studies. A random-effects model was used for meta-analysis, and linear Meta-regression and non-linear dose-response analysis were performed to assess whether the effect of folic acid supplementation was affected by the dose and duration of intervention. Cochrane tools were also used to assess the risk of bias in the included studies.

RESULTS

Twenty-one studies, including 2025 participants (1010 cases and 1015 controls), were included in the present meta-analysis. Folic acid supplementation significantly affected the percentage of flow-mediated dilation (FMD%) (WMD: 2.59%; 95% CI: 1.51, 3.67; P < 0.001) and flow-mediated dilation (FMD) (WMD: 24.38 μm; 95% CI: 3.08, 45.68; P = 0.025), but not end-diastolic diameter (EDD) (WMD: 0.21 mm; 95% CI: - 0.09, 0.52; P = 0.176), and intercellular adhesion molecule (ICAM) (WMD: 0.18 ng/ml; 95% CI: - 10.02, 13.81; P = 0.755).

CONCLUSIONS

These findings suggest that folic acid supplementation may improve endothelial function by increasing FMD and FMD% levels.

TRIAL REGISTRATION

PROSPERO registration cod: CRD42021289744.

Roles of Oxidative Stress and Inflammation in Vascular Endothelial Dysfunction-Related Disease

Oxidative stress and chronic inflammation play an important role in the pathogenesis of atherosclerosis. Atherosclerosis develops as the first step of vascular endothelial dysfunction induced by complex molecular mechanisms. Vascular endothelial dysfunction leads to oxidative stress and inflammation of vessel walls, which in turn enhances vascular endothelial dysfunction. Vascular endothelial dysfunction and vascular wall oxidative stress and chronic inflammation make a vicious cycle that leads to the development of atherosclerosis. Simultaneously capturing and accurately evaluating the association of vascular endothelial function with oxidative stress and inflammation would be useful for elucidating the pathophysiology of atherosclerosis, determining treatment efficacy, and predicting future cardiovascular complications. Intervention in both areas is expected to inhibit the progression of atherosclerosis and prevent cardiovascular complications.

Protective Effects of Polyphenols Present in Mediterranean Diet on Endothelial Dysfunction

Endothelial dysfunction tends to be the initial indicator in proinflammatory state and macro- and microvascular complications, such as atherosclerosis and cardiovascular diseases. It has been shown that certain compounds in diet can generate beneficial effects on cardiovascular disease due to its interactions with endothelial cells. Thus, this review is aimed at investigating whether certain polyphenols present in the Mediterranean diet, specifically catechin, quercetin, resveratrol, and urolithin, could exert positive effects on endothelial dysfunction. After analysis of numerous papers, we found that polyphenols aiding endothelial function is beneficial not only for patients with cardiovascular disease, diabetes, or endothelial dysfunction but for all people as it can improve the effects of aging on the endothelia. The additional benefit of these polyphenols on weight loss further improves health and lowers the risk of several diseases, including those caused by endothelial dysfunction. However, it is important to note that the dosages in the majorities of the studies mentioned in this review were of supplemental rather than nutritionally relevant quantities, and therefore, the recommended dosages are difficult to determine.

The role of nutraceuticals in prevention and treatment of hypertension: An updated review of the literature

Hypertension (HTN) is a worldwide epidemic in both developed and developing countries. It is one of the leading causes of major health problems such as cardiovascular disease, stroke, and heart attack. In recent years, several studies have reported associations between specific dietary ingredients and improving HTN. Nutraceuticals are natural food components with pharmacological properties. Reports suggest that functional foods and nutraceutical ingredients might support patients to obtain the desired therapeutic blood pressure (BP) goals and reduce cardiovascular risks by modulating various risk factors such as oxidative stress, renin-angiotensin system hyperactivity, inflammation, hyperlipidemia, and vascular resistance. We review the recent clinical experiments that have evaluated the biological and pharmacological activities of several types of nutraceuticals, including sour tea, cocoa, common spices, vitamin C, vitamin E, lycopene, flavonoids, coenzyme Q10, milk's tripeptides, calcium, magnesium, polyunsaturated fatty acids, and prebiotics in preventing and treating HTN. This review summarizes recent knowledge about the impact of common nutraceuticals for the regulation of BP.