Effects of dark chocolate and cocoa consumption on endothelial function and arterial stiffness in overweight adults

The role of cocoa flavanols in modulating peripheral and cerebral microvascular function in healthy individuals and populations at-risk of cardiovascular disease: a systematic review

BACKGROUND

Cocoa flavanols (CFs) are polyphenolic molecules with proposed cardioprotective effects. Whilst extensive evidence supports their ability to ameliorate vasodilator responses within conduit vessels, their actions in the microvasculature are less clear. This systematic review of the literature aimed to determine whether CF interventions lead to improvements in microvascular vasodilator responses in healthy populations and those with increased cardiovascular disease risk.

METHODS

Database searches were conducted up to September 2023 using Medline, Embase, Pubmed and Web of Science Core Collection to identify randomised, placebo-controlled, human studies investigating the effect of CF interventions on the microvasculature (at rest and vasodilator responses). All studies were assessed for risk of-bias according to Cochrane Collaboration recommendations for randomised-controlled trials, data were extracted from studies and findings collated by vote-counting.

RESULTS

Searches identified 511 unique articles for screening, of which 19 were selected for data extraction. Vasodilator responses were enhanced in 85.7% (80.4-91.0%, p = 0.013) of all acute studies (n = 13), and in 81.8% (74.1-89.4%, p = 0.065) of studies in healthy subgroups (n = 11). Importantly, this effect was apparent in all studies with 'low risk of bias' (n = 8, p = 0.008). In contrast, there was no effect of acute CF interventions at rest. For chronic studies (n = 7), the effect of CFs was less clear, with a significant benefit reported at rest only, in all young, healthy subgroups (n = 7, p = 0.016), but no evidence of improvements in vasodilator responses.

CONCLUSIONS

CFs have the potential to improve microvascular function, particularly in healthy individuals, with benefits appearing more pronounced following acute CF supplementation. Despite this, interpretations are limited by the small number of comparable studies identified and the heterogeneity of populations studied. Overall, the effects of CFs on the microvasculature seem to be less consistent than previous evidence in the macrovasculature, suggesting that the microvessels may be less susceptible to the effect of CFs than conduit arteries.

REGISTRATION

The PROSPERO registration number for this review is CRD42023483814.

Cocoa flavanol supplementation in optimizing post-exercise glycemic control in rats with normoglycemia or diabetes mellitus: findings from the ECODIA study

OBJECTIVE

This study investigated the acute effects of cocoa flavanol (CF) supplementation on glucose homeostasis, aerobic performance, and lactate concentration in rats with type 1 diabetes mellitus (T1DM), type 2 diabetes mellitus (T2DM), and normoglycemia (NORM).

MATERIALS AND METHODS

The study included 28 male Wistar rats (220-290 g). Induction of T1DM (n = 8) was achieved through intraperitoneal injection of streptozotocin, while T2DM (n = 10) was induced using an ad libitum high-fat diet combined with a fructose-rich beverage. The rats in the NORM group (n = 10) received a standard diet for 30 days. Two experiments were conducted: (1) T1DM rats performed two successive 30-minute treadmill runs below the anaerobic threshold and (2) T2DM and NORM rats underwent two incremental maximal treadmill running tests, both after CF or placebo supplementation. Blood glucose concentrations were measured from pre-exercise to 60 minutes post-exercise.

RESULTS

Glycemic reduction at 60 minutes post-exercise was significantly potentiated by CF compared with placebo supplementation in T1DM, T2DM, and normoglycemic rats (p < 0.05 for all). In T2DM rats, CF induced a glycemic response comparable to the NORM placebo-supplemented condition. These effects of CF persisted despite variations in aerobic performance or lactate concentration after incremental exercise.

CONCLUSION

Supplementation with CF prior to physical exercise elicited a pronounced post-aerobic exercise glycemic reduction. This represents a promising strategy for mitigating the duration of hyperglycemia exposure after physical exercise.

Enhancing metabolic and inflammatory status in insulin-resistant rats: Acute intervention with cocoa flavanols and submaximal aerobic exercise activates intracellular signaling pathways for glucose metabolism

INTRODUCTION

Type 2 diabetes, characterized by hyperglycemia, is closely linked to obesity and low-grade inflammation. Acute cocoa flavanols (CF) intake has demonstrated benefits in vasoreactivity, cognitive functions, and antioxidant enzyme activity. However, the physiological mechanisms of CF concerning glucose uptake, inflammatory mediators, and their interplay with aerobic exercise remain unclear in populations with metabolic diseases.

OBJECTIVE

This study aims to investigate the acute effects of CF, alone or combined with acute aerobic exercise on mechanisms involved in glucose uptake and inflammatory mediators in the liver, skeletal muscle, pancreas, and adipose tissue in insulin-resistant (IR) rats.

METHODS

Sixty-four Wistar rats (250 ± 10g; 15 weeks age) were subjected to a regular chow (CON) or an obesity-associated insulin-resistant (IR) state induced by a high-fat diet and fructose-rich beverage for 30 days. Seventy-two hours after an incremental maximal treadmill running test, rats received a placebo solution or CF supplementation (45 mg·kg-1 of body weight). One hour later, they either rested or ran on a treadmill at 60 % of peak oxygen uptake (VO2peak) for 30 min. Euthanasia occurred 30 min post-experimental sessions. Inflammatory and anti-inflammatory cytokines were assayed using ELISA in the liver, pancreas, gastrocnemius muscle, and epididymal adipose tissues. TRB3 and CPT1 mRNA were assessed by q-RTPCR in the liver and gastrocnemius muscle while Akt and AMPK phosphorylation were examined by immunohistochemistry.

RESULTS

CF attenuated hyperglycemia observed after submaximal aerobic exercise in IR rats (p < 0.001). In the liver, CF exhibited additive effects to aerobic exercise, enhancing Akt protein phosphorylation, potentially contributing to improved glucose uptake in IR rats. Submaximal aerobic exercise and CF increased AMPK protein phosphorylation in the liver (p < 0.001) and skeletal muscle (p < 0.001), reduced TRB3 gene expression (p < 0.01), elevated CPT-1a gene expression (p < 0.001), and ameliorated the inflammatory milieu in the pancreas, adipose tissue, liver, and gastrocnemius muscle.

CONCLUSION

Acute intake, of CF combined with submaximal aerobic exercise activates key proteins and genes involved in glucose uptake and lipid metabolism, improving the inflammatory milieu. This synergistic effect may contribute to mitigating metabolic complications associated with insulin resistance.

Effect of dark chocolate/ cocoa consumption on oxidative stress and inflammation in adults: A GRADE-assessed systematic review and dose-response meta-analysis of controlled trials

BACKGROUND

Oxidative stress and inflammation play critical roles in the pathogenesis of many chronic diseases. Dark chocolate (DC)/cocoa, as a rich source of polyphenols like flavonoids, has anti-inflammatory and antioxidant properties that may confer health benefits, but findings in this context are inconsistent.

OBJECTIVE

This systematic review and dose-response meta-analysis aimed to provide a comprehensive overview of the controlled trials (CTs) that have examined the effects of DC/cocoa on oxidative stress and inflammation biomarkers in adults.

SEARCH METHODS

Databases including PubMed, Web of Science, and Scopus, were searched for relevant studies through April 2024.

SELECTION CRITERIA

Studies assessed C-reactive protein (CRP), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), malondialdehyde (MDA), nitric oxide (NO), P-selectin, E-selectin and thiobarbituric acid reactive substances (TBARS) in adults were included.

DATA ANALYSIS

Based on the random-effects model, we calculated WMDs, SMDs and 95 % confidence intervals (CIs). Sensitivity, sub-group, meta-regression and dose-response analyses were also conducted.

RESULTS

Thirty-three eligible CTs with 1379 participants were included. All studies reported the intervention types (cocoa powder, beverages and chocolate bars) and dosage. However, sixteen studies didn't do/report testing for purity and potency by independent groups. Also, none of the studies mentioned the risk of contamination with heavy metals. Another limitation was the lack of blinding assessment in studies. DC/cocoa significantly reduced MDA (SMD: -0.69, 95 %CI: -1.17, -0.2, p = 0.005) and increased NO levels (SMD: 2.43, 95 %CI: 1.11,3.75, p < 0.001); However, it has no significant effects on the other outcomes. Greater anti-inflammatory effects occurred at higher flavonoid doses (>450 mg/day) and for shorter durations (≤4 weeks) in the non-healthy participants. Non-linear dose-response relationships between cocoa dosage and CRP level and also between flavonoid dosage and IL-6 level were observed. Based on the GRADE evaluation, just CRP and MDA results were considered as high certainty evidence and the other outcomes results were categorized as very low to moderate certainty.

CONCLUSIONS

DC/cocoa may improve systemic oxidative status and inflammation in adults. However, further studies should be performed to determine its benefits.

Flavan-3-ols and Vascular Health: Clinical Evidence and Mechanisms of Action

Cardiovascular diseases (CVDs) are one of the main causes of mortality and morbidity worldwide. A healthy diet rich in plant-derived compounds such as (poly)phenols appears to have a key role in improving cardiovascular health. Flavan-3-ols represent a subclass of (poly)phenols of great interest for their possible health benefits. In this review, we summarized the results of clinical studies on vascular outcomes of flavan-3-ol supplementation and we focused on the role of the microbiota in CVD. Clinical trials included in this review showed that supplementation with flavan-3-ols mostly derived from cocoa products significantly reduces blood pressure and improves endothelial function. Studies on catechins from green tea demonstrated better results when involving healthy individuals. From a mechanistic point of view, emerging evidence suggests that microbial metabolites may play a role in the observed effects. Their function extends beyond the previous belief of ROS scavenging activity and encompasses a direct impact on gene expression and protein function. Although flavan-3-ols appear to have effects on cardiovascular health, further studies are needed to clarify and confirm these potential benefits and the rising evidence of the potential involvement of the microbiota.

Short-term cocoa bioflavanol supplementation does not improve cold-induced vasodilation in young healthy adults

PURPOSE

Cold-induced vasodilation (CIVD) is an oscillatory rise in blood flow to glabrous skin that occurs in cold-exposed extremities. Dietary flavanols increase bioavailable nitric oxide, a proposed mediator of CIVD through active vasodilation and/or withdrawal of sympathetic vascular smooth muscle tone. However, no studies have examined the effects of flavanol intake on extremity skin perfusion during cold exposure. We tested the hypothesis that acute and 8-day flavanol supplementation would augment CIVD during single-digit cold water immersion (CWI).

METHODS

Eleven healthy adults (24 ± 6 years; 10 M/1F) ingested cocoa flavanols (900 mg/day) or caffeine- and theobromine-matched placebo for 8 days in a double-blind, randomized, crossover design. On Days 1 and 8, CIVD was assessed 2 h post-treatment. Subjects immersed their 3rd finger in warm water (42 °C) for 15 min before CWI (4 °C) for 30 min, during which nail bed and finger pad skin temperature were measured.

RESULTS

Flavanol ingestion had no effect on CIVD frequency (Day 1, Flavanol: 3 ± 2 vs. Placebo: 3 ± 2; Day 8, Flavanol: 3 ± 2 vs. Placebo: 3 ± 1) or amplitude (Day 1, Flavanol: 4.3 ± 1.7 vs. Placebo: 4.9 ± 2.6 °C; Day 8, Flavanol: 3.9 ± 1.9 vs. Placebo: 3.9 ± 2.0 °C) in the finger pad following acute or 8-day supplementation (P > 0.05). Furthermore, average, nadir, and apex finger pad temperatures during CWI were not different between treatments on Days 1 or 8 of supplementation (P > 0.05). Similarly, no differences in CIVD parameters were observed in the nail bed following supplementation (P > 0.05).

CONCLUSION

These data suggest that cocoa flavanol ingestion does not alter finger CIVD. Clinical Trial Registration Clinicaltrials.gov Identifier: NCT04359082. April 24, 2020.

Personal Strategies to Reduce the Cardiovascular Impacts of Environmental Exposures

Ubiquitous environmental exposures increase cardiovascular disease risk via diverse mechanisms. This review examines personal strategies to minimize this risk. With regard to fine particulate air pollution exposure, evidence exists to recommend the use of portable air cleaners and avoidance of outdoor activity during periods of poor air quality. Other evidence may support physical activity, dietary modification, omega-3 fatty acid supplementation, and indoor and in-vehicle air conditioning as viable strategies to minimize adverse health effects. There is currently insufficient data to recommend specific personal approaches to reduce the adverse cardiovascular effects of noise pollution. Public health advisories for periods of extreme heat or cold should be observed, with limited evidence supporting a warm ambient home temperature and physical activity as strategies to limit the cardiovascular harms of temperature extremes. Perfluoroalkyl and polyfluoroalkyl substance exposure can be reduced by avoiding contact with perfluoroalkyl and polyfluoroalkyl substance-containing materials; blood or plasma donation and cholestyramine may reduce total body stores of perfluoroalkyl and polyfluoroalkyl substances. However, the cardiovascular impact of these interventions has not been examined. Limited utilization of pesticides and safe handling during use should be encouraged. Finally, vasculotoxic metal exposure can be decreased by using portable air cleaners, home water filtration, and awareness of potential contaminants in ground spices. Chelation therapy reduces physiological stores of vasculotoxic metals and may be effective for the secondary prevention of cardiovascular disease.

Effects of flavanols and procyanidins-rich cocoa consumption on metabolic syndrome: an update review (2013-2023)

Studies indicated that cocoa-based products effectively mitigate the risks associated with metabolic syndrome (MetS), however, the effect varies based on cocoa types, dosages, and study durations. This review aimed to determine the flavanol-rich cocoa consumption on MetS outcomes within the last decade (2013-2023), adhering to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Seven randomized-controlled trials (RCTs) used cocoa-based products containing 0.3-1680 mg flavanol monomers and 3.5-1270 mg procyanidins. Cocoa-based products beneficially reduced glycemic response, blood pressure and lipid profiles. However, this review highlights little evidence pinpointing the best cocoa products type and required dosage for the observed effects. Further intervention aiming to improve MetS should justify the selection and concentration of flavanols (monomers and procyanidins). A robust study design should consider registering the trials before study commencement, consider multicenter RCT trials, and adjust for potential covariates that might "masked" the outcomes.

Dark chocolate intake and cardiovascular diseases: a Mendelian randomization study

Previous intervention studies have shown some benefits of dark chocolate for the cardiovascular system, but it has not been established whether dark chocolate intake is associated with the risk of cardiovascular diseases (CVDs). To investigate the causality between dark chocolate intake and the risk of CVDs, a Mendelian randomization (MR) study was conducted. We obtained summary-level data on dark chocolate intake and CVDs from publicly available genome-wide association studies. In this MR study, the main approach was to use a fixed-effect model with inverse variance weighted (IVW) and evaluate the robustness of the results via sensitivity analysis. We found that dark chocolate intake was significantly associated with the reduction of the risk of essential hypertension (EH) (OR = 0.73; 95% CI 0.60-0.88; p = 1.06 × 10-3), as well as with the suggestive association to the reduced risk of venous thromboembolism (OR = 0.69; 95% CI 0.50-0.96; p = 2.81 × 10-2). However, no association was found between dark chocolate intake and the other ten CVDs. Our study provides evidence for a causality between dark chocolate intake and a reduced risk of EH, which has important implications for the prevention of EH in the population.

How Healthy Is It to Fortify Cocoa-Based Products with Cocoa Flavanols? A Comprehensive Review

(1) Background: Cocoa's healthy benefits may be attributed to the potent antioxidant activity of cocoa polyphenols, mainly flavanols, which have been characterised as existing in a high concentration in cocoa. However, the phenolic composition of cocoa and cocoa-derived products is highly variable, and manufacturing processes might significantly reduce their phenolic content. For that reason, the full characterisation of cocoa and cocoa-derived products before evaluating their bioactivity is crucial. The aim of this review is to analyse the available evidence on the effect of flavanol-fortified cocoa-derived products on human health. (2) Methods: Forty-eight clinical trials focused on the health effect of consuming flavanol-fortified drinks, bars and chocolate have been reviewed, with a total of 1523 subjects. (3) Results: Although studies differ widely in methodology, dosage, duration, and target population, beneficial effects of flavanol-rich cocoa consumption have been observed at doses ranging from 45.3 mg/d to 1078 mg/d, especially on cardiovascular health and cognitive function. (4) Conclusions: Considering the high consumption and acceptability of cocoa and cocoa-derived products, the fortification of cocoa products as well as other highly consumed foods with cocoa flavanols could be an effective strategy for health promotion.

The Influence of Polyphenols on Atherosclerosis Development

Polyphenols have attracted tremendous attention due to their pro-health properties, including their antioxidant, anti-inflammatory, antibacterial and neuroprotective activities. Atherosclerosis is a vascular disorder underlying several CVDs. One of the main risk factors causing atherosclerosis is the type and quality of food consumed. Therefore, polyphenols represent promising agents in the prevention and treatment of atherosclerosis, as demonstrated by in vitro, animal, preclinical and clinical studies. However, most polyphenols cannot be absorbed directly by the small intestine. Gut microbiota play a crucial role in converting dietary polyphenols into absorbable bioactive substances. An increasing understanding of the field has confirmed that specific GM taxa strains mediate the gut microbiota-atherosclerosis axis. The present study explores the anti-atherosclerotic properties and associated underlying mechanisms of polyphenols. Moreover, it provides a basis for better understanding the relationship between dietary polyphenols, gut microbiota, and cardiovascular benefits.

Mexican Ancestral Foods (Theobroma cacao, Opuntia ficus indica, Persea americana and Phaseolus vulgaris) Supplementation on Anthropometric, Lipid and Glycemic Control Variables in Obese Patients: A Systematic Review and Meta-Analysis

Diet containing Mexican ancestral foods such as cocoa, nopal, avocado, and common bean have been individually reported to have beneficial effects on obesity and comorbidities. Methods: A systematic review and meta-analysis on the effect of Mexican ancestral foods on the anthropometric, lipid, and glycemic control variables in obese patients was performed following PRISMA guidelines. Data were analyzed using a random-effects model. Results: We selected 4664 articles from an initial search, of which only fifteen studies satisfied the inclusion criteria. Data for 1670 participants were analyzed: 843 in the intervention group and 827 in the control group. A significant reduction in body mass index (mean difference: −0.80 (−1.31 to −0.30)) (95% confidence interval), p = 0.002, heterogeneity I2 = 92% was showed after the ingestion of cocoa, nopal, avocado, or common bean. The mean difference for body weight was −0.57 (−1.93 to 0.79), waist of circumference: −0.16 (−2.54 to −2.21), total cholesterol: −5.04 (−11.5 to 1.08), triglycerides: −10.11 (−27.87 to 7.64), fasting glucose: −0.81 (−5.81 to 4.19), and insulin: −0.15 (−0.80 to 0.50). Mexican ancestral food supplementation seems to improve anthropometric, lipid, and glycemic control variables in obesity; however, more randomized controlled trials are needed to have further decisive evidence about dosage and method of supplementation and to increase the sample size.

Coconut sugar derived from coconut inflorescence sap lowers systolic blood pressure and arterial stiffness in middle-aged and older adults: a pilot study

Nutraceutical-based interventions hold promise to reduce blood pressure (BP) and arterial stiffness, which are two cardiovascular disease (CVD) risk factors. However, the effects of coconut sap powder (CSP), an Asian sweetener and novel nutraceutical, on BP and arterial stiffness in middle-aged and older adults (MA/O, ≥45 yr) has yet to be established. We hypothesized CSP will decrease BP and arterial stiffness in MA/O adults. In a double-blind, randomized, placebo-controlled study design, 19 (age 55.3 ± 2.1 yr) MA/O adults completed measures of brachial and carotid BP, and arterial stiffness [carotid-femoral pulse wave velocity (cfPWV), common carotid artery (CCA) β-stiffness, compliance, distensibility, and Young's and Peterson's Elastic moduli] before and after 8 wk of CSP (1.5 g/day) or placebo (1.5 g/day). A two-way repeated-measures analysis of variance was used to compare group mean differences. Compared with placebo, CSP lowered brachial systolic BP (SBP) (CSP pre: 117.4 ± 2.9 vs. post: 109.0 ± 2.4 mmHg, P < 0.05), but not carotid SBP (P = 0.12). CSP also lowered Young's (CSP pre: 5,514.4 ± 1,115.4 vs. post: 3,690.6 ± 430.9 kPa) and Peterson's elastic moduli (CSP pre: 22.2 ± 4.4 vs. post: 19.2 ± 4.5 kPa) (P < 0.05, both). A trend for CSP to lower CCA β-stiffness (P = 0.06) and increase CCA compliance (P = 0.07) was also observed. Arterial stiffness assessed by cfPWV did not change (P > 0.05). No inflammatory or antioxidant biomarkers were affected by CSP. In summary, 8 wk of CSP lowers brachial SBP and CCA mechanical stiffness indicating a potential cardioprotective effect in MA/O adults.NEW & NOTEWORTHY Blood pressure (BP) and arterial stiffness are important predictors of cardiovascular health with aging. Nutraceuticals are an easy-to-implement lifestyle strategy demonstrating promise to effectively lower BP and arterial stiffness with aging and ultimately cardiovascular disease risk. We demonstrate that coconut sap powder (CSP), a traditional Asian sweetener, lowers brachial systolic BP and carotid artery mechanical stiffness in middle-aged and older (MA/O) adults. These findings provide initial evidence for the CSP-related cardioprotective effects in MA/O adults.

Effect of Cocoa Beverage and Dark Chocolate Consumption on Blood Pressure in Those with Normal and Elevated Blood Pressure: A Systematic Review and Meta-Analysis

Cocoa is a major dietary source of polyphenols, including flavanols, which have been associated with reduced blood pressure (BP). While earlier systematic reviews and meta-analyses have shown significant effects of cocoa consumption on systolic BP, limitations include small sample sizes and study heterogeneity. Questions regarding food matrix and dose of polyphenols, flavanols, or epicatechins remain. This systematic review and meta-analysis aimed to investigate the effects of ≥2 weeks of cocoa consumption as a beverage or dark chocolate in those with normal or elevated (< or ≥130 mmHg) systolic BP measured in the fasted state or over 24-h. A systematic search conducted on PubMed and Cochrane Library databases up to 26 February 2022 yielded 31 suitable articles. Independent of baseline BP, cocoa consumption for ≥2 weeks was associated with reductions in systolic and diastolic BP (p < 0.05, all). Compared with cocoa, chocolate lowered the weighted mean of resting systolic BP (−3.94 mmHg, 95% CI [−5.71, −2.18]) more than cocoa beverage (−1.54 mmHg, 95% CI [−3.08, 0.01]). When the daily dose of flavanols was ≥900 mg or of epicatechin ≥100 mg, the effect was greater. Future, adequately powered studies are required to determine the optimal dose for a clinically significant effect.

A Proprietary Herbal Blend Containing Extracts of Punica granatum Fruit Rind and Theobroma cocoa Seeds Increases Serum Testosterone Level in Healthy Young Males: A Randomized, Double-Blind Placebo-Controlled Study

LN18178 is a proprietary herbal blend containing extracts of Punica granatum fruit rind and Theobroma cocoa seeds. The objective of the present study was to evaluate the effect of LN18178 on serum testosterone levels in healthy young adults in a randomized, double-blind, placebo-controlled study. One hundred and twenty male volunteers (age 21-35 years) were randomized into three groups. Each group (n = 40) received a daily dose of either placebo or 200 or 400 mg LN18178 for fifty-six days. An increase in serum testosterone (free and total) was the primary efficacy measure of the study. The secondary measures included dihydrotestosterone (DHT), cortisol, Luteinizing hormone (LH), 17β-Estradiol (E2), hand grip strength, and the mid-upper arm circumferences (MUAC). The vital signs and clinical chemistry parameters in blood and urine were performed to determine product safety. Post-intervention, both doses of LN18178 significantly increased free testosterone (p < 0.0001 vs. baseline; p = 0.0268 and p < 0.0001, respectively vs. placebo). The high dose group showed significant increases in total testosterone (p < 0.0001 vs. baseline; p = 0.0184 vs. placebo) and luteinizing hormone (p < 0.0007 vs. baseline; p = 0.0470 vs. placebo). The changes in other hormones were not significant. At post-trial, the LN18178-400 group showed significant improvements in the hand grip strength and mid-upper arm circumference. The hemato-biochemical parameters, urinalysis, and vital signs of the participants were within the normal range. Together, these observations suggest that LN18178 is a safe and tolerable herbal blend; it increases testosterone level and increases muscle strength and MUAC in young, healthy males.Supplemental data for this article is available online at https://doi.org/10.1080/19390211.2022.2035037 .

Efficacy of flavonoids-containing supplements on insulin resistance and associated metabolic risk factors in overweight and obese subjects: a systematic review and meta-analysis of 25 randomized controlled trials

BACKGROUND

Obesity is becoming a global epidemic. Flavonoids, with anti-inflammatory and antioxidative functions, are proposed to treat insulin resistance (IR) in obese subjects. We aimed to evaluate the effectiveness and safety of flavonoids-containing supplements on IR and associated metabolic risk factors in overweight and obese participants.

METHODS

Randomized controlled trials (RCTs) involving flavonoids-containing supplements used to treat overweight and obese subjects with results of IR, other associated metabolic risk factors, and adverse effects published were retrieved from 5 electronic databases from the year of inception to January 2, 2022.

RESULTS

Twenty-five RCTs (n = 1950) were included. Pooled results demonstrated that HOMA-IR in the group receiving flavonoids-containing supplements significantly decreased versus the control group (WMD = -0.132, 95% CI: -0.236 to -0.027, p = 0.013). Subgroup analyses showed that HOMA-IR in the subgroup receiving flavonoid-containing mixtures significantly decreased (WMD = -0.25, 95% CI: -0.43 to -0.06, p = 0.008), whereas such result was not found in the singly-used flavonoids subgroup (WMD = -0.08, 95% CI: -0.20 to 0.05, p = 0.240). In addition, QUICKI in the experimental group had an increasing trend compared to that in the control group (WMD = 0.01, 95% CI: -0.00 to 0.02, p = 0.065). For secondary outcomes, FBG, FBI, TC, TG, SBP, weight, BMI, and WHR in the group receiving flavonoids-containing supplements dropped significantly compared to those in the controls (WMD = -0.05, 95% CI: -0.08 to -0.02, p = 0.002; WMD = -0.58, 95% CI: -1.04 to -0.12, p = 0.014; WMD = -0.04, 95% CI: -0.06 to -0.03, p < 0.001; WMD = -0.04, 95% CI: -0.05 to -0.03, p < 0.001; WMD = -2.01, 95% CI: -3.17 to -0.86, p = 0.001; WMD = -0.29, 95% CI: -0.49 to -0.09, p = 0.004; WMD = -0.10 95% CI: -0.17 to -0.04, p = 0.003; WMD = -0.10, 95% CI: -0.01 to -0.00, p = 0.015; respectively). Adverse reactions did not differ between the group receiving flavonoids-containing supplements and the control group (RR = 0.97, 95% CI: 0.62 to 1.52, p = 0.905).

CONCLUSION

This study showed that flavonoids-containing supplements may be efficacious and safe in improving IR and associated metabolic risk factors in overweight and obese participants. Nevertheless, doubt over the findings remains because limited RCTs per type of flavonoids-containing supplement were investigated, and many of the RCTs had a small sample size. Therefore, the findings must be validated in future research.

SYSTEMATIC REVIEW REGISTRATION

https://inplasy.com/inplasy-2022-2-0011/, identifier INPLASY202220011.

The Relationship Between Dietary Choices and Health and Premature Vascular Ageing

The paper aims to review the available data about the main mechanisms enabling improvement or accelerating vascular ageing due to food choices, considering recent experimental and clinical data, and emphasising potential implications for clinical practice and therapy. The main food choices which will be discussed are diets rich in fruits and vegetables, the Mediterranean diet, polyunsaturated fatty acids, cocoa, caffeine, tea, meat, dairy products, sodium, and potassium intake.

Timing of chocolate intake affects hunger, substrate oxidation, and microbiota: A randomized controlled trial

Eating chocolate in the morning or in the evening/at night, may differentially affect energy balance and impact body weight due to changes in energy intake, substrate oxidation, microbiota (composition/function), and circadian-related variables. In a randomized controlled trial, postmenopausal females (n = 19) had 100 g of chocolate in the morning (MC), in the evening/at night (EC), or no chocolate (N) for 2 weeks and ate any other food ad libitum. Our results show that 14 days of chocolate intake did not increase body weight. Chocolate consumption decreased hunger and desire for sweets (P < .005), and reduced ad libitum energy intake by ~300 kcal/day during MC and ~150 kcal/day during EC (P = .01), but did not fully compensate for the extra energy contribution of chocolate (542 kcal/day). EC increased physical activity by +6.9%, heat dissipation after meals +1.3%, and carbohydrate oxidation by +35.3% (P < .05). MC reduced fasting glucose (4.4%) and waist circumference (-1.7%) and increased lipid oxidation (+25.6%). Principal component analyses showed that both timings of chocolate intake resulted in differential microbiota profiles and function (P < .05). Heat map of wrist temperature and sleep records showed that EC induced more regular timing of sleep episodes with lower variability of sleep onset among days than MC (60 min vs 78 min; P = .028). In conclusion, having chocolate in the morning or in the evening/night results in differential effects on hunger and appetite, substrate oxidation, fasting glucose, microbiota (composition and function), and sleep and temperature rhythms. Results highlight that the "when" we eat is a relevant factor to consider in energy balance and metabolism.

Stimulatory effects of (-)-epicatechin and its enantiomer (+)-epicatechin on mouse frontal cortex neurogenesis markers and short-term memory: proof of concept

Consumption of (-)-epicatechin (Epi), a cacao flavanol improves cognition. The aim was to compare the effects of (-)-Epi or its stereoisomer (+)-Epi on mouse frontal cortex-dependent short-term working memory and modulators of neurogenesis. Three-month-old male mice (n = 7 per group) were provided by gavage either water (vehicle; Veh), (-)-Epi, at 1 mg kg-1 or (+)-Epi at 0.1 mg per kg of body weight for 15 days. After treatment, spontaneous alternation was evaluated by Y-maze. Brain frontal cortex was isolated for nitrate/nitrite measurements, Western blotting for nerve growth factor (NGF), microtubule associated protein 2 (MAP2), endothelial and neuronal nitric oxide synthase (eNOS and nNOS) and immunohistochemistry for neuronal specific protein (NeuN), doublecortin (DCX), capillary (CD31) and neurofilaments (NF200). Results demonstrate the stimulatory capacity of (-)-Epi and (+)-Epi on markers of neuronal proliferation as per increases in immunoreactive cells for NeuN (74 and 120% respectively), DCX (70 and 124%) as well as in NGF (34.4, 63.6%) and MAP2 (41.8, 63.8%). Capillary density yielded significant increases with (-)-Epi (∼80%) vs. (+)-Epi (∼160%). CD31 protein levels increased with (-)-Epi (∼70%) and (+)-Epi (∼140%). Effects correlated with nitrate/nitrite stimulation by (-)-Epi and (+)-Epi (110.2, 246.5%) and enhanced eNOS phosphorylation (Ser1177) with (-)-Epi and (+)-Epi (21.4, 41.2%) while nNOS phosphorylation only increased with (+)-Epi (18%). Neurofilament staining was increased in (-)-Epi by 135.6 and 84% with (+)-Epi. NF200 increased with (-)-Epi (116%) vs. (+)-Epi (84.5%). Frontal cortex-dependent short-term spatial working improved with (-)-Epi and (+)-Epi (15, 13%). In conclusion, results suggest that both enantiomers, but more effectively (+)-Epi, upregulate neurogenesis markers likely through stimulation of capillary formation and NO triggering, improvements in memory.

Evolution of cocoa flavanol analytics: impact on reporting and cross-study comparison

Cocoa flavanols (CF) are a group of dietary bioactives that have been studied for their potential health benefits for over two decades. In this time, multiple methods for CF testing have evolved, introducing the potential for differences in reported CF content. The reliable characterization of CF content in food and test materials used in clinical studies is critical to comparisons of research studies over time, as well as critical to enabling the systematic reviews and meta-analyses required to support dietary recommendations of bioactives. In this work, we compared two analytical methods that have been widely applied to characterize materials used in clinical research and a method newly recognized by AOAC as the official method for CF analysis. Differences in accuracy of -36% to +20% were observed when comparing CF contents determined with these methods, supporting the notion that CF values determined across methods are not directly comparable. To address differences, a linear regression model was developed to predict CF values. This approach was cross-validated and directly applied to the conversion of CF values published in key scientific papers on the benefits of CF. This work provides a valid tool to compare CF values reported across these different methods and enables comparisons and interpretation of studies investigating the bioactivity of CF.

Impact of cocoa flavanols on human health

Cocoa is a source of flavanols, and these phenolic compounds exert beneficial effects on health and aging, and reduce the risk of suffering chronic diseases (cardiovascular diseases, metabolic disorders, cancer). An increasing body of evidence has emerged to suggest that cocoa flavanols potentially are important chemopreventive natural agents. This review summarizes human studies from the past two decades, providing data related to the effects derived from cocoa intake on health and disease. Most human studies have reported beneficial effects of cocoa consumption on health and chronic diseases; however, outcomes are not unequivocal. Review of human studies enable to identify different mechanisms of action for cocoa, although they are not fully understood at present. In addition, it remains unclear whether cocoa consumption should be recommended to healthy subjects or to patients and what is the appropriate dosage or duration of cocoa consumption. Elucidation of information regarding these crucial issues could lead to cocoa use as an approach for decreasing the risk of certain chronic diseases, as well as improving health and quality of life.

Effects of Cocoa Polyphenols and Dark Chocolate on Obese Adults: A Scoping Review

Obesity remains a major public health problem due to its increasing prevalence. Natural products have become common as adjunct therapeutic agents for treating obesity and preventing metabolic diseases. Cocoa and its products are commonly consumed worldwide. Dark chocolate, a rich source of polyphenols, has received attention lately for its beneficial role in the management of obesity; however, conflicting results are still being reported. This scoping review aims to provide a comprehensive understanding of the existing literature on the relationship and effects of cocoa and dark chocolate intake among obese adults. We searched multiple databases for research investigating the consumption of cocoa and/or dark chocolate in managing obesity among adults. This review includes epidemiological and human studies that were published in English over the last 10 years. Our review of the current literature indicates that epidemiological and human trials with obese adults have shown inconsistent results, which may be due to the different populations of subjects, and different types of cocoa products and doses used for intervention. Studies among obese adults are mainly focusing on obese individuals with comorbidities, as such more studies are needed to elucidate the role of cocoa polyphenols in weight control and preventing the risk of chronic diseases among obese individuals without comorbidities as well as healthy individuals. Careful adjustment of confounding factors would be required. The effects of cocoa and dark chocolate intake on obese adults were discussed, and further research is warranted to identify the gaps.

The sweet side of dark chocolate for chronic kidney disease patients

Chocolate is a widely appreciated foodstuff with historical appreciation as a food from the gods. In addition to its highly palatable taste, it is a rich source of (poly)phenolics, which have several proposed salutogenic effects, including neuroprotective anti-inflammatory, anti-oxidant and cardioprotective capabilities. Despite the known benefits of this ancient foodstuff, there is a paucity of information on the effects of chocolate in the context of chronic kidney disease (CKD). This review focusses on the potential salutogenic contribution of chocolate intake, to mitigate inflammatory and oxidative burden in CKD, its potential, for cardiovascular protection and on the maintenance of diversity in gut microbiota, as well as clinical perspectives, on regular chocolate intake by CKD patients.

Effects of Cocoa-Rich Chocolate on Blood Pressure, Cardiovascular Risk Factors, and Arterial Stiffness in Postmenopausal Women: A Randomized Clinical Trial

This study aimed to evaluate the effects of the intake of 10 g of cocoa-rich chocolate on blood pressure, other cardiovascular risk factors, and vascular structure and function in postmenopausal women. A total of 140 postmenopausal women participated in this randomized and controlled parallel clinical trial. For six months, the intervention group (IG; n = 73) consumed daily 10 g of chocolate (99% cocoa) added to their usual food intake, whereas the control group (CG; n = 67) did not receive any intervention. Blood pressure, pulse pressure (PP), cardio-ankle vascular index (CAVI), ankle-brachial index (ABI), brachial-ankle pulse wave velocity (baPWV), augmentation index, and laboratory variables were measured at baseline and six months. ANCOVA analyses adjusted for baseline values revealed no significant differences for systolic blood pressure (−1.45 mm Hg; 95% confidence interval (CI): −4.79, 1.88; p = 0.391) or baPWV (0.18 m/s; 95% CI: −0.14, 0.50; p = 0.263) between groups. A decrease in PP was observed in the IG compared to the CG (−2.05 mm Hg; 95% CI: −4.08, −0.02; p = 0.048). The rest of the vascular structure and function parameters and other measured variables remained unchanged. The daily intake of 10 g of cocoa-rich chocolate seems to provide little improvement to cardiovascular health, but neither does it cause any adverse effects on the parameters evaluated in postmenopausal women in the long term.

Strengthening the Immune System and Reducing Inflammation and Oxidative Stress through Diet and Nutrition: Considerations during the COVID-19 Crisis

The coronavirus-disease 2019 (COVID-19) was announced as a global pandemic by the World Health Organization. Challenges arise concerning how to optimally support the immune system in the general population, especially under self-confinement. An optimal immune response depends on an adequate diet and nutrition in order to keep infection at bay. For example, sufficient protein intake is crucial for optimal antibody production. Low micronutrient status, such as of vitamin A or zinc, has been associated with increased infection risk. Frequently, poor nutrient status is associated with inflammation and oxidative stress, which in turn can impact the immune system. Dietary constituents with especially high anti-inflammatory and antioxidant capacity include vitamin C, vitamin E, and phytochemicals such as carotenoids and polyphenols. Several of these can interact with transcription factors such as NF-kB and Nrf-2, related to anti-inflammatory and antioxidant effects, respectively. Vitamin D in particular may perturb viral cellular infection via interacting with cell entry receptors (angiotensin converting enzyme 2), ACE2. Dietary fiber, fermented by the gut microbiota into short-chain fatty acids, has also been shown to produce anti-inflammatory effects. In this review, we highlight the importance of an optimal status of relevant nutrients to effectively reduce inflammation and oxidative stress, thereby strengthening the immune system during the COVID-19 crisis.

Chronic and acute effects of cocoa products intake on arterial stiffness and platelet count and function: A systematic review and dose-response Meta-analysis of randomized clinical trials

The findings of trials investigating the effect of cocoa products consumption on vascular stiffness and platelet are controversial. The aim of this study is to summarize the findings on the acute and chronic effects of different forms of cocoa on the risk factors of cardiovascular disease. We searched SCOPUS, Pub Med and Web of Science from inception to Jan 2020. Finally, the random-effect model was used to report the pooled effect sizes. Results are expressed as weighted mean difference (WMD) with 95% confidence intervals (CI).Overall, 41 trials were included, of which only 14 studies met the eligibility criteria for analysis, including 11 long-term RCTs (more than a week was considered as a chronic phase) and 7 short-term RCTs (less than a week was considered as an acute phase). According to the result of 11 long-term RCTs, cocoa products had a negative significant effect on pulse wave velocity; PWV (WMD: -0.33 m/s, P < 0.0001), Augmentation index; AIx (WMD: -4.50%, P = 0.001) but had no significant effect on platelet count (WMD: -10.41 10⁹/L, P = 0.053). Also, according to the results of 7 short-term RCTs, cocoa products had a negative significant effect on PWV (WMD: -0.27 m/s, P = 0.019), AIx (WMD: -4.47%, P = 0.003).Current study indicated the beneficial effect of acute and chronic consumption of cocoa-based products ingestion on platelet function and arterial stiffness in healthy adult regardless of age especially in male and for consumption (≤4 weeks) in the chronic intake and (≤120 minutes) in acute intake, but did not affect on platelet count. However, further studies are required to shed light on this issue.

Short-Term Effects of Dark Chocolate on Retinal and Choriocapillaris Perfusion in Young, Healthy Subjects Using Optical Coherence Tomography Angiography

(1) Aim: Contrasting results have been published on the effect of dark chocolate on visual function. The aim of this study was to evaluate retinal and choriocapillaris perfusion, using optical coherence tomography angiography (OCT-A), and visual function in healthy subjects following dark chocolate ingestion. (2) Methods: This prospective randomized study was carried out on 18 healthy young subjects at the St. Andrea Hospital, Sapienza, University of Rome. Visual acuity assessment and a complete ophthalmologic examination were carried out at baseline. In session one, each subject was randomized to eat either a 100 g dark chocolate bar or a 100 g white chocolate bar. In session two, the opposite chocolate was given to each participant. OCT-A and best corrected visual acuity (BCVA) were performed before the chocolate was eaten and repeated 1, 2, and 3 h after that. Retinal vessel density and choriocapillaris flow area were assessed. (3) Results: 18 patients with a mean (SD) age of 26.3 (1.5) years were included. No significant differences between dark or white chocolate were found when evaluating foveal density (%), whole density (%), choriocapillaris flow area, and BCVA. (4) Conclusions: Dark chocolate did not result in significant changes in retinal perfusion and choriocapillaris flow area. However, given the results of other studies showing the positive effects of flavonoids on visual function, further studies are warranted using pure chocolate without other components such as caffeine that can potentially affect results. Furthermore, we cannot rule out the possible benefits of higher doses of flavonoids in dietary supplementation over a more extended period and in a larger patient population.

Improving the reporting quality of intervention trials addressing the inter-individual variability in response to the consumption of plant bioactives: quality index and recommendations

PURPOSE

The quality of the study design and data reporting in human trials dealing with the inter-individual variability in response to the consumption of plant bioactives is, in general, low. There is a lack of recommendations supporting the scientific community on this topic. This study aimed at developing a quality index to assist the assessment of the reporting quality of intervention trials addressing the inter-individual variability in response to plant bioactive consumption. Recommendations for better designing and reporting studies were discussed.

METHODS

The selection of the parameters used for the development of the quality index was carried out in agreement with the scientific community through a survey. Parameters were defined, grouped into categories, and scored for different quality levels. The applicability of the scoring system was tested in terms of consistency and effort, and its validity was assessed by comparison with a simultaneous evaluation by experts' criteria.

RESULTS

The "POSITIVe quality index" included 11 reporting criteria grouped into four categories (Statistics, Reporting, Data presentation, and Individual data availability). It was supported by detailed definitions and guidance for their scoring. The quality index score was tested, and the index demonstrated to be valid, reliable, and responsive.

CONCLUSIONS

The evaluation of the reporting quality of studies addressing inter-individual variability in response to plant bioactives highlighted the aspects requiring major improvements. Specific tools and recommendations favoring a complete and transparent reporting on inter-individual variability have been provided to support the scientific community on this field.

Relation of Fruits and Vegetables with Major Cardiometabolic Risk Factors, Markers of Oxidation, and Inflammation

Noncommunicable diseases (NCDs) are considered to be the leading cause of death worldwide. Inadequate fruit and vegetable intake have been recognized as a risk factor for almost all NCDs (type 2 diabetes mellitus, cancer, and cardiovascular and neurodegenerative diseases). The main aim of this review is to examine the possible protective effect that fruit and vegetable consumption or their bioactive compounds may have on the development of NCDs such as atherosclerosis. The accumulated evidence on the protective effects of adequate consumption of fruits and vegetables in some cases, or the lack of evidence in others, are summarized in the present review. The main conclusion of this review is that well-designed, large-scale, long-term studies are needed to truly understand the role fruit and vegetable consumption or their bioactive compounds have in atherosclerosis.

Impact of Foods and Dietary Supplements Containing Hydroxycinnamic Acids on Cardiometabolic Biomarkers: A Systematic Review to Explore Inter-Individual Variability

Plant-based diets rich in bioactive compounds such as polyphenols have been shown to positively modulate the risk of cardiometabolic (CM) diseases. The inter-individual variability in the response to these bioactives may affect the findings. This systematic review aimed to summarize findings from existing randomized clinical trials (RCTs) evaluating the effect of hydroxycinnamic acids (HCAs) on markers of CM health in humans. Literature searches were performed in PubMed and the Web of Science. RCTs on acute and chronic supplementation of HCA-rich foods/extracts on CM biomarkers were included. Forty-four RCTs (21 acute and 23 chronic) met inclusion criteria. Comparisons were made between RCTs, including assessments based on population health status. Of the 44 RCTs, only seven performed analyses on a factor exploring inter-individual response to HCA consumption. Results demonstrated that health status is a potentially important effect modifier as RCTs with higher baseline cholesterol, blood pressure and glycaemia demonstrated greater overall effectiveness, which was also found in studies where specific subgroup analyses were performed. Thus, the effect of HCAs on CM risk factors may be greater in individuals at higher CM risk, although future studies in these populations are needed, including those on other potential determinants of inter-individual variability. PROSPERO, registration number CRD42016050790.

Dietary Polyphenols Targeting Arterial Stiffness: Interplay of Contributing Mechanisms and Gut Microbiome-Related Metabolism

Increased arterial stiffness is a degenerative vascular process, progressing with age that leads to a reduced capability of arteries to expand and contract in response to pressure changes. This progressive degeneration mainly affects the extracellular matrix of elastic arteries and causes loss of vascular elasticity. Recent studies point to significant interference of dietary polyphenols with mechanisms involved in the pathophysiology and progression of arterial stiffness. This review summarizes data from epidemiological and interventional studies on the effect of polyphenols on vascular stiffness as an illustration of current research and addresses possible etiological factors targeted by polyphenols, including pathways of vascular functionality, oxidative status, inflammation, glycation, and autophagy. Effects can either be inflicted directly by the dietary polyphenols or indirectly by metabolites originated from the host or microbial metabolic processes. The composition of the gut microbiome, therefore, determines the resulting metabolome and, as a consequence, the observed activity. On the other hand, polyphenols also influence the intestinal microbial composition, and therefore the metabolites available for interaction with relevant targets. As such, targeting the gut microbiome is another potential treatment option for arterial stiffness.

Insight of Stability of Procyanidins in Free and Liposomal Form under an in Vitro Digestion Model: Study of Bioaccessibility, Kinetic Release Profile, Degradation, and Antioxidant Activity

Small unilamellar and multilayered liposomes loaded with polymeric (epi)catechins up to pentamers were produced. The bioaccessibility, kinetic release profile, and degradation under in vitro gastrointestinal conditions were monitored by UHPLC-DAD-QTOF-MS/MS. The results show that all of the procyanidins underwent depolymerization and epimerization into small molecular oligomers and mainly to (epi)catechin subunits. Moreover, all of the liposome formulations presented higher bioaccessibility and antioxidant activity in comparison to their respective counterparts in non-encapsulated form. Similar results were obtained with procyanidins from cocoa extract-loaded liposomes. Namely, the bioaccessibility of dimer, trimer, and tetramer fractions from cocoa-loaded liposomes were 4.5-, 2.1-, and 9.3-fold higher than those from the non-encapsulated cocoa extract. Overall, the procyanidin release profile was dependent on their chemical structure and physicochemical interaction with the lipid carrier. These results confirmed that liposomes are efficient carriers to stabilize and transport procyanidins with the aim of enhancing their bioaccessibility at a controlled release rate.

Effect of Alpha-Lipoic Acid Supplementation on Endothelial Function and Cardiovascular Risk Factors in Overweight/Obese Youths: A Double-Blind, Placebo-Controlled Randomized Trial

Endothelial dysfunction is recognized as an early sign of systemic atherosclerosis, and it represents a therapeutic target to prevent long-term cardiovascular (CV) consequences. Alpha-lipoic acid (ALA) is a commonly used dietary supplement exerting anti-oxidant and anti-inflammatory effects. We investigated whether a three-month treatment with ALA improves endothelial function, as assessed by flow-mediated dilation (FMD) of the brachial artery, and clinical and metabolic risk factors in overweight/obese youths. We enrolled 67 overweight/obese children, and 22 normal-weight metabolically healthy controls. Overweight/obese youths were randomly allocated in a double-blinded manner to receive ALA (n = 34) or placebo (n = 33). Of these, 64 (32 ALA, 32 placebo) completed the follow-up. At baseline, in ALA and placebo groups, FMD was similar, but lower as compared with that in controls (p = 0.045). At three months, within the ALA and placebo groups, FMD did not change significantly. However, the basal and peak diameter of brachial artery significantly increased after ALA treatment as compared to placebo (p = 0.036 and p = 0.01, respectively). There were no significant within- and between-group changes for anthropometric and metabolic variables. The results show that ALA supplementation improves vascular tone and may have a beneficial effect on CV health in overweight/obese youths.

Vascular and cognitive effects of cocoa-rich chocolate in postmenopausal women: a study protocol for a randomised clinical trial

INTRODUCTION

The intake of polyphenols has certain health benefits. This study will aim to assess the effect of adding a daily amount of chocolate high in cocoa content and polyphenols to the normal diet on blood pressure, vascular function, cognitive performance, quality of life and body composition in postmenopausal women.

METHODS AND ANALYSIS

Here we plan a randomised clinical trial with two parallel groups involving a total of 140 women between 50 and 64 years in the postmenopausal period, defined by amenorrhoea of ​​at least 12 consecutive months. The main variable will be the change in blood pressure. Secondary variables will be changes in vascular function, quality of life, cognitive performance and body composition. The intervention group will be given chocolate containing 99% cocoa, with instructions to add 10 g daily to their normal diet for 6 months. The daily nutritional contribution of this amount of chocolate is 59 kcal and 65.4 mg of polyphenols. There will be no intervention in the control group. All variables will be measured at the baseline visit and 3 and 6 months after randomisation, except cognitive performance and quality of life, which will only be assessed at baseline and at 6 months. Recruitment is scheduled to begin on 1 June 2018, and the study will continue until 31 May 2019.

ETHICS AND DISSEMINATION

This study was approved by the Clinical Research Ethics Committee of the Health Area of Salamanca, Spain ('CREC of Health Area of Salamanca'), in February 2018. A SPIRIT checklist is available for this protocol. The clinical trial has been registered at ClinicalTrials.gov provided by the US National Library of Medicine, number NCT03492983. The results will be disseminated through open access peer-reviewed journals, conference presentations, broadcast media and a presentation to stakeholders.

A systems biology network analysis of nutri(epi)genomic changes in endothelial cells exposed to epicatechin metabolites

Although vasculo-protective effects of flavan-3-ols are widely accepted today, their impact on endothelial cell functions and molecular mechanisms of action involved is not completely understood. The aim of this study was to characterize the potential endothelium-protective effects of circulating epicatechin metabolites and to define underlying mechanisms of action by an integrated systems biology approach. Reduced leukocyte rolling over vascular endothelium was observed following epicatechin supplementation in a mouse model of inflammation. Integrative pathway analysis of transcriptome, miRNome and epigenome profiles of endothelial cells exposed to epicatechin metabolites revealed that by acting at these different levels of regulation, metabolites affect cellular pathways involved in endothelial permeability and interaction with immune cells. In-vitro experiments on endothelial cells confirmed that epicatechin metabolites reduce monocyte adhesion and their transendothelial migration. Altogether, our in-vivo and in-vitro results support the outcome of a systems biology based network analysis which suggests that epicatechin metabolites mediate their vasculoprotective effects through dynamic regulation of endothelial cell monocyte adhesion and permeability. This study illustrates complex and multimodal mechanisms of action by which epicatechin modulate endothelial cell integrity.

Effects of superfoods on risk factors of metabolic syndrome: a systematic review of human intervention trials

Functional foods can be effective in the prevention of metabolic syndrome and subsequently the onset of cardiovascular diseases and type II diabetes mellitus. More recently, however, another term was introduced to describe foods with additional health benefits: "superfoods", for which, to date, no generally accepted definition exists. Nonetheless, their consumption might contribute to the prevention of metabolic syndrome, for example due to the presence of potentially bioactive compounds. This review provides an overview of controlled human intervention studies with foods described as "superfoods" and their effects on metabolic syndrome parameters. First, an Internet search was performed to identify foods described as superfoods. For these superfoods, controlled human intervention trials were identified until April 2017 investigating the effects of superfood consumption on metabolic syndrome parameters: waist circumference or BMI, blood pressure, or concentrations of HDL cholesterol, triacylglycerol or glucose. Seventeen superfoods were identified, including a total of 113 intervention trials: blueberries (8 studies), cranberries (8), goji berries (3), strawberries (7), chili peppers (3), garlic (21), ginger (10), chia seed (5), flaxseed (22), quinoa (1), cocoa (16), maca (1), spirulina (7), wheatgrass (1), acai berries (0), hemp seed (0) and bee pollen (0). Overall, only limited evidence was found for the effects of the foods described as superfoods on metabolic syndrome parameters, since results were not consistent or the number of controlled intervention trials was limited. The inconsistencies might have been related to intervention-related factors, such as duration or dose. Furthermore, conclusions may be different if other health benefits are considered.

A serving of blueberry (V. corymbosum) acutely improves peripheral arterial dysfunction in young smokers and non-smokers: two randomized, controlled, crossover pilot studies

Several studies have documented the important role of polyphenol-rich foods in the modulation of vascular remodelling and function. This study aimed to evaluate the capacity of a single portion of blueberry (V. corymbosum) to acutely improve peripheral arterial dysfunction in a group of young volunteers. Twenty-four healthy males (12 non-smokers and 12 smokers) were recruited for two different randomized, controlled, crossover pilot acute studies. In the first study, non-smokers were exposed to a control treatment (C; 300 mL of water with sugar) and a blueberry treatment (BB; 300 g of blueberry). In the second study, smokers underwent 3 different protocols: (1) - smoking treatment (S); (2) - control treatment (CS; 300 mL of water with sugar + smoking); (3) - blueberry treatment (BS; 300 g of blueberry + smoking). Each treatment (1 day long) was separated by a one week washout period. Blood pressure, peripheral arterial function (reactive hyperemia index, RHI, a marker of endothelial function) and arterial stiffness (digital augmentation index, dAix and dAix normalized by considering a heart rate of 75 bpm, dAix@75) were measured before and after each treatment. In the first study, the consumption of blueberry and control treatment acutely increased peripheral arterial function in the group of non-smokers. The improvement in RHI was higher and significantly different after blueberry treatment compared to the control treatment (54.8 ± 8.4% BB vs. 28.2 ± 8.3% C; p = 0.01). No effects were observed for markers of arterial stiffness, blood pressure and heart rate. Acute cigarette smoke significantly increased blood pressure and heart rate, while no significant effect was registered in peripheral arterial function and stiffness. The intake of blueberry and control treatment before a cigarette did not counteract the increase in blood pressure and heart rate, while it significantly improved peripheral arterial function. In particular, a significant increase was observed following BS (35.2 ± 7.5% RHI; p = 0.02) and CS treatments (34.6 ± 11.9% RHI; p = 0.02) when compared to only smoking treatment. No difference between BS and CS was detected. In conclusion, the intake of blueberry and control treatments acutely improved peripheral arterial dysfunction both in smoker and in non-smoker subjects. Further studies should be performed to confirm the results obtained and reveal the potential mechanisms of blueberry in the improvement of endothelial function.

Total Hip Replacement Provokes Endothelial Dysfunction

Surgery represents an increased risk of different perioperative complications. Endothelial function (EF) is a key mechanism responsible for cardiovascular homeostasis and is involved in thromboembolic complications. We aimed to follow changes of EF in an early postoperative period in patients undergoing total hip replacement (THR). Endothelial function was assessed noninvasively in 70 consecutive patients who underwent an elective THR under spinal anesthesia. Flow-mediated dilation (FMD) and low flow-mediated constriction capability of the brachial artery, which are indicators of EF were measured before the operation (baseline), 24 hours after the operative procedure, and 5 to 7 days postoperatively. Baseline FMD was 12.3% and decreased a day after surgery to 7.3% ( P < .001). After 5 to 7 days, it gradually increased to 9.2%. However, on average, it was lower than before surgery ( P < .001). The median duration of THR was 85.0 (65.0-100.0) minutes, the average hospital length of stay was 7 days. Total hip replacement is associated with an immediate decrease in FMD which remains significantly decreased 5 to 7 days after the surgery compared with the preoperative value. These results indicate that surgery provokes endothelial dysfunction and deteriorates cardiovascular homeostasis. This effect could be involved in cardiovascular complications in the postoperative period.

Nutraceuticals as therapeutic agents for atherosclerosis

Atherosclerosis, a chronic inflammatory disorder of medium and large arteries and an underlying cause of cardiovascular disease (CVD), is responsible for a third of all global deaths. Current treatments for CVD, such as optimized statin therapy, are associated with considerable residual risk and several side effects in some patients. The outcome of research on the identification of alternative pharmaceutical agents for the treatment of CVD has been relatively disappointing with many promising leads failing at the clinical level. Nutraceuticals, products from food sources with health benefits beyond their nutritional value, represent promising agents in the prevention of CVD or as an add-on therapy with current treatments. This review will highlight the potential of several nutraceuticals, including polyunsaturated fatty acids, flavonoids and other polyphenols, as anti-CVD therapies based on clinical and pre-clinical mechanism-based studies.

Does cocoa/dark chocolate supplementation have favorable effect on body weight, body mass index and waist circumference? A systematic review, meta-analysis and dose-response of randomized clinical trials

Background: Cocoa and dark chocolate (DC) have been reported to be effective for health promotion; however the exact effect of cocoa/DC on anthropometric measures have not been yet defined. Methods: A comprehensive search to identify randomized clinical trials investigating the impact of cocoa/DC on body weight, body mass index (BMI) and waist circumference (WC) was performed up to December 2017. A meta-analysis of eligible studies was performed using random effects model to estimate pooled effect size. Fractional polynominal modeling was used to explore dose-response relationships. Results: A total of 35 RCTs investigated the effects of cocoa/DC on weight, BMI and WC were included. Meta-analysis did not suggest any significant effect of cocoa/DC supplementation on body weight (-0.108 kg, 95% CI -0.262, 0.046 P = 0.168), BMI (-0.014 kg/m² 95% CI -0.105, 0.077, P: 0.759,) and WC (0.025 cm 95% CI -0.083, 0.129, P = 0.640). Subgroup analysis revealed that that weight and BMI were reduced with cocoa/DC supplementation ≥ 30 g chocolate per day in trials between 4-8 weeks. Cocoa/DC consumption resulted in WC reduction in non-linear fashion (r = 0.042, P-nonlinearity = 0.008).Conclusion: Cocoa/DC supplementation does not reduce anthropometric measures significantly. However subgroup analysis regarding dose (≥ 30 g/day) and duration (between 4 to 8 weeks) revealed significant reduction of body weight and BMI.

Functional Food and Cardiovascular Disease Prevention and Treatment: A Review

Cardiovascular disease (CVD) is now the leading cause of death globally and is a growing health concern. Lifestyle factors, including nutrition, play an important role in the etiology and treatment of CVD. Functional foods based on their basic nutritional functions can decrease the risk of many chronic diseases and have some physiological benefits. They contain physiologically active components either from plant or animal sources, marketed with the claim of their ability to reduce heart disease risk, focusing primarily on established risk factors, which are hyperlipidemia, diabetes, metabolic syndrome, obesity/overweight, elevated lipoprotein A level, small dense low-density lipoprotein cholesterol (LDL-C), and elevated inflammatory marker levels. Functional foods are suspected to exert their cardioprotective effects mainly through blood lipid profile level and improve hypertension control, endothelial function, platelet aggregation, and antioxidant actions. Clinical and epidemiological observations indicate that vegetable and fruit fiber, nuts and seeds, sea foods, coffee, tea, and dark chocolate have cardioprotective potential in humans, as well whole-grain products containing intact grain kernels rich in fiber and trace nutrients. They are nutritionally more important because they contain phytoprotective substances that might work synergistically to reduce cardiovascular risk. This review will focus on the reciprocal interaction between functional foods and the potential link to cardiovascular health and the possible mechanisms of action.

Do flavanols-rich natural products relieve obesity-related insulin resistance?

Growing evidence support that insulin resistance may occur as a severe problem due to chronic energetic overfeeding and subsequent obesity. When an abundance of glucose and saturated fat enter the cell, impaired blood flow, hypoxia, inflammation and macrophage infiltration in obese adipose tissue may induce oxidative stress and insulin resistance. Excessive circulating saturated fatty acids ectopically accumulate in insulin-sensitive tissues and impair insulin action. In this context, excessive hepatic lipid accumulation may play a central, pathogenic role in insulin resistance. It is thought that dietary polyphenols may ameliorate obesity-related insulin resistance by attenuating inflammatory responses and oxidative stress. The most often occurring natural polyphenolic compounds are flavonoids. In this review, the possible mechanistic effect of flavonoid-rich natural products on insulin resistance-related metabolic pathways is discussed. Polyphenol intake can prevent high-fat-diet-induced insulin resistance via cell surface G protein-coupled estrogen receptors by upregulating the expression of related genes, and their pathways, which are responsible for the insulin sensitivity.

Effects of Dark Chocolate and Almonds on Cardiovascular Risk Factors in Overweight and Obese Individuals: A Randomized Controlled-Feeding Trial

BACKGROUND

Consumption of almonds or dark chocolate and cocoa has favorable effects on markers of coronary heart disease; however, the combined effects have not been evaluated in a well-controlled feeding study. The aim of this study was to examine the individual and combined effects of consumption of dark chocolate and cocoa and almonds on markers of coronary heart disease risk.

METHODS AND RESULTS

A randomized controlled, 4-period, crossover, feeding trial was conducted in overweight and obese individuals aged 30 to 70 years. Forty-eight participants were randomized, and 31 participants completed the entire study. Each diet period was 4 weeks long, followed by a 2-week compliance break. Participants consumed each of 4 isocaloric, weight maintenance diets: (1) no treatment foods (average American diet), (2) 42.5 g/d of almonds (almond diet [ALD]), (3) 18 g/d of cocoa powder and 43 g/d of dark chocolate (chocolate diet [CHOC]), or (4) all 3 foods (CHOC+ALD). Compared with the average American diet, total cholesterol, non-high-density lipoprotein cholesterol, and low-density lipoprotein cholesterol after the ALD were lower by 4%, 5%, and 7%, respectively (P<0.05). The CHOC+ALD decreased apolipoprotein B by 5% compared with the average American diet. For low-density lipoprotein subclasses, compared with the average American diet, the ALD showed a greater reduction in large buoyant low-density lipoprotein particles (-5.7±2.3 versus -0.3±2.3 mg/dL; P=0.04), whereas the CHOC+ALD had a greater decrease in small dense low-density lipoprotein particles (-12.0±2.8 versus -5.3±2.8 mg/dL; P=0.04). There were no significant differences between diets for measures of vascular health and oxidative stress.

CONCLUSIONS

Our results demonstrate that consumption of almonds alone or combined with dark chocolate under controlled-feeding conditions improves lipid profiles. Incorporating almonds, dark chocolate, and cocoa into a typical American diet without exceeding energy needs may reduce the risk of coronary heart disease.

CLINICAL TRIAL REGISTRATION

URL: https://www.clinicaltrials.gov. Unique identifier: NCT01882881.