High-cocoa polyphenol-rich chocolate improves HDL cholesterol in Type 2 diabetes patients

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.

Cocoa Extract Supplementation and Risk of Type 2 Diabetes: The Cocoa Supplement and Multivitamin Outcomes Study (COSMOS) Randomized Clinical Trial

OBJECTIVE

Observational studies have indicated that cocoa flavanol supplementation may be a promising strategy for type 2 diabetes (T2D) prevention. We aimed to directly evaluate its clinical efficacy in a large randomized clinical trial (RCT).

RESEARCH DESIGN AND METHOD

The Cocoa Supplement and Multivitamin Outcomes Study (COMSOS) was a 2 × 2 factorial RCT performed from June 2015 to December 2020 that tested cocoa extract and a multivitamin for the prevention of cardiovascular disease (CVD) and cancer. A total of 21,442 U.S. adults free of CVD and recent cancer, including 12,666 women aged ≥65 years and 8,776 men aged ≥60 years, were randomly assigned to receive cocoa extract [500 mg/day cocoa flavanols, including 80 mg (-)-epicatechin] or placebo. In this study, we included 18,381 participants without diabetes at enrollment and examined the effect of cocoa extract supplementation on incident self-reported T2D in intention-to-treat analyses.

RESULTS

During a median follow-up of 3.5 years, 801 incident T2D cases were reported. Compared with placebo, taking a cocoa extract supplement did not reduce T2D (adjusted hazard ratio 1.04, 95% CI 0.91-1.20, P = 0.58). Stratification analyses showed that the effect of cocoa extract supplementation was not significantly modified by sex, race, BMI, smoking, physical activity, dietary quality, flavanol status at baseline, or randomized multivitamin assignment.

CONCLUSIONS

Middle-aged and older adults taking a cocoa extract supplement for a median of 3.5 years did not reduce their risk of incident T2D. Further studies of cocoa extract supplementation beginning earlier in adulthood and in populations with different background diets are warranted.

Role of flavonoids in controlling obesity: molecular targets and mechanisms

Obesity presents a major health challenge that increases the risk of several non-communicable illnesses, such as but not limited to diabetes, hypertension, cardiovascular diseases, musculoskeletal and neurological disorders, sleep disorders, and cancers. Accounting for nearly 8% of global deaths (4.7 million) in 2017, obesity leads to diminishing quality of life and a higher premature mortality rate among affected individuals. Although essentially dubbed as a modifiable and preventable health concern, prevention, and treatment strategies against obesity, such as calorie intake restriction and increasing calorie burning, have gained little long-term success. In this manuscript, we detail the pathophysiology of obesity as a multifactorial, oxidative stress-dependent inflammatory disease. Current anti-obesity treatment strategies, and the effect of flavonoid-based therapeutic interventions on digestion and absorption, macronutrient metabolism, inflammation and oxidative stress and gut microbiota has been evaluated. The use of several naturally occurring flavonoids to prevent and treat obesity with a long-term efficacy, is also described.

The Effect of Bioactive Aliment Compounds and Micronutrients on Non-Alcoholic Fatty Liver Disease

In the current review, we focused on identifying aliment compounds and micronutrients, as well as addressed promising bioactive nutrients that may interfere with NAFLD advance and ultimately affect this disease progress. In this regard, we targeted: 1. Potential bioactive nutrients that may interfere with NAFLD, specifically dark chocolate, cocoa butter, and peanut butter which may be involved in decreasing cholesterol concentrations. 2. The role of sweeteners used in coffee and other frequent beverages; in this sense, stevia has proven to be adequate for improving carbohydrate metabolism, liver steatosis, and liver fibrosis. 3. Additional compounds were shown to exert a beneficial action on NAFLD, namely glutathione, soy lecithin, silymarin, Aquamin, and cannabinoids which were shown to lower the serum concentration of triglycerides. 4. The effects of micronutrients, especially vitamins, on NAFLD. Even if most studies demonstrate the beneficial role of vitamins in this pathology, there are exceptions. 5. We provide information regarding the modulation of the activity of some enzymes related to NAFLD and their effect on this disease. We conclude that NAFLD can be prevented or improved by different factors through their involvement in the signaling, genetic, and biochemical pathways that underlie NAFLD. Therefore, exposing this vast knowledge to the public is particularly important.

Cocoa Flavanol Supplementation and the Effect on Insulin Resistance in Females Who Are Overweight or Obese: A Randomized, Placebo-Controlled Trial

There is interest in the impact that dietary interventions can have on preventing the transition from insulin resistance to type 2 diabetes, including a suggestion that the bioactive components of cocoa may enhance fasting insulin sensitivity. However, a role for cocoa flavanols (CF) in reducing insulin resistance in the insulin-stimulated state, an important risk factor for cardiovascular disease, is unresolved. This study investigated whether CF consumption improved whole-body insulin-mediated glucose uptake ('M') in females with overweight/obesity, using a randomized, double-blinded, placebo-controlled, parallel-group design. Thirty-two premenopausal females (19-49 years; 27-35 kg·m^-2) with elevated HOMA-IR (HOMA-IR >1.5) supplemented their habitual diet with two servings/day of a high-flavanol cocoa drink (HFC; 609 mg CF/serving; n = 16) or low-flavanol cocoa drink (LFC; 13 mg CF/serving; n = 16) for 4 weeks. Assessment of HOMA-IR and 'M' during a 3-h, 60 mIU insulin·m^-2·min^-1 euglycemic clamp was performed before and after the intervention. Data are the mean (SD). Changes to HOMA-IR (HFC -0.003 (0.57); LFC -0.0402 (0.86)) and 'M' (HFC 0.99 (7.62); LFC -1.32 (4.88) µmol·kg^-1·min^-1) after the intervention were not different between groups. Four weeks' consumption of ~1.2 g CF/day did not improve indices of fasting insulin sensitivity or insulin-mediated glucose uptake. A recommendation for dietary supplementation with cocoa flavanols to improve glycemic control is therefore not established.

A comprehensive insight on modern green analyses for quality control determination and processing monitoring in coffee and cocoa seeds

Green analysis is defined as the analysis of chemicals in a manner where sample extraction and analysis are performed with least amounts of steps, low hazardous materials, while maintaining efficiency in terms of analytes detection. Coffee and cocoa represent two of the most popular and valued beverages worldwide in addition to their several products i.e., cocoa butter, chocolates. This study presents a comprehensive overview of green methods used to evaluate cocoa and coffee seeds quality compared to other conventional techniques highlighting advantages and or limitations of each. Green techniques discussed in this review include solid phase microextraction, spectroscopic techniques i.e., infra-red (IR) spectroscopy and nuclear magnetic resonance (NMR) besides, e-tongue and e-nose for detection of flavor. The employment of multivariate data analysis in data interpretation is also highlighted in the context of identifying key components pertinent to specific variety, processing method, and or geographical origin.

Proanthocyanidins and Where to Find Them: A Meta-Analytic Approach to Investigate Their Chemistry, Biosynthesis, Distribution, and Effect on Human Health

Proanthocyanidins (PACs) are a class of polyphenolic compounds that are attracting considerable interest in the nutraceutical field due to their potential health benefits. However, knowledge about the chemistry, biosynthesis, and distribution of PACs is limited. This review summarizes the main chemical characteristics and biosynthetic pathways and the main analytical methods aimed at their identification and quantification in raw plant matrices. Furthermore, meta-analytic approaches were used to identify the main plant sources in which PACs were contained and to investigate their potential effect on human health. In particular, a cluster analysis identified PACs in 35 different plant families and 60 different plant parts normally consumed in the human diet. On the other hand, a literature search, coupled with forest plot analyses, highlighted how PACs can be actively involved in both local and systemic effects. Finally, the potential mechanisms of action through which PACs may impact human health were investigated, focusing on their systemic hypoglycemic and lipid-lowering effects and their local anti-inflammatory actions on the intestinal epithelium. Overall, this review may be considered a complete report in which chemical, biosynthetic, ecological, and pharmacological aspects of PACs are discussed.

Chocolate consumption and all-cause and cause-specific mortality in a US population: a post hoc analysis of the PLCO cancer screening trial

Few studies with mixed results have examined the association between chocolate consumption and mortality. We aimed to examine this association in a US population. A population-based cohort of 91891 participants aged 55 to 74 years was identified. Chocolate consumption was assessed via a food frequency questionnaire. Cox regression was used to estimate risk estimates. After an average follow-up of 13.5 years, 19586 all-cause deaths were documented. Compared with no regular chocolate consumption, the maximally adjusted hazard ratios of all-cause mortality were 0.89 [95% confidence interval (CI) 0.84-0.94], 0.84 (95% CI 0.79-0.90), 0.86 (95% CI 0.81-0.93), and 0.87 (95% CI 0.82-0.93) for >0-0.5 servings/week, >0.5-1 serving/week, >1-2 servings/week, and >2 servings/week, respectively (Ptrend = 0.009). A somewhat stronger inverse association was observed for mortality from cardiovascular disease and Alzheimer's disease. A nonlinear dose-response pattern was found for all-cause and cardiovascular mortality (all Pnonlinearity < 0.01), with the lowest risk observed at chocolate consumption of 0.7 servings/week and 0.6 servings/week, respectively. The favorable associations with all-cause and cardiovascular mortality were found to be more pronounced in never smokers than in current or former smokers (all Pinteraction < 0.05). In conclusion, chocolate consumption confers reduced risks of mortality from all causes, cardiovascular disease, and Alzheimer's disease in this US population.

Dietary Flavonoids and Insulin Signaling in Diabetes and Obesity

Type 2 diabetes (T2D) and obesity are relevant worldwide chronic diseases. A common complication in both pathologies is the dysregulation of the insulin-signaling pathway that is crucial to maintain an accurate glucose homeostasis. Flavonoids are naturally occurring phenolic compounds abundant in fruits, vegetables and seeds. Rising evidence supports a role for the flavonoids against T2D and obesity, and at present, these compounds are considered as important potential chemopreventive agents. This review summarizes in vitro and in vivo studies providing data related to the effects of flavonoids and flavonoid-rich foods on the modulation of the insulin route during T2D and obesity. Notably, few human studies have evaluated the regulatory effect of these phenolic compounds at molecular level on the insulin pathway. In this context, it is also important to note that the mechanism of action for the flavonoids is not fully characterized and that a proper dosage to obtain a beneficial effect on health has not been defined yet. Further investigations will contribute to solve all these critical challenges and will enable the use of flavonoids to prevent, delay or support the treatment of T2D and obesity.

The effect of cocoa/dark chocolate consumption on lipid profile, glycemia, and blood pressure in diabetic patients: A meta-analysis of observational studies

Due to the increasing rate of cardiovascular disease and related risk factors in the worldin recent decades, the present meta-analysis was performed to investigate the effects ofcocoa/chocolate consumption on lipid profile, glycemia, and blood pressure control in diabetic patients. A systematic search of the databases PubMed, Scopus, Web of Science, and Cochran Library was performed up to July 2020. All randomized controlled trials (RCTs) using cocoa/dark chocolate in diabetic patients were included in the study. The search results were limited to English-language publications. Eight RCTs, including 433 participants, were selected for this meta-analysis. Pooled analysis indicated a significant reduction in low-density lipoprotein cholesterol LDL-c levels (WMD: -15.49 mg/dl; 95% CI: -24.56, -6.42, p = .001) and fasting blood sugar (FBS) concentrations (WMD: -6.88 mg/dl; 95% CI: -13.28, -0.48, p = .03) following cocoa/dark chocolate consumption. The analysis of papers included in current study indicates that the consumption of cocoa/dark chocolate reduced the serum fasting blood glucose (FBS) and LDL cholesterol concentrations. However, further high quality trials are essential for confirming the clinical efficacy of cocoa/dark chocolate consumption on complete metabolic profile.

Acute Effects of Cocoa Flavanols on Blood Pressure and Peripheral Vascular Reactivity in Type 2 Diabetes Mellitus and Essential Hypertension: A Protocol for an Acute, Randomized, Double-Blinded, Placebo-Controlled Cross-Over Trial

Introduction: Patients with type 2 diabetes mellitus are at high risk to develop vascular complications resulting in high morbidity and mortality. Cocoa flavanols are promising nutraceuticals with possible beneficial vascular effects in humans. However, limited research is currently available on the vascular effects in a diabetic population with inconsistent results. Possible reasons for this inconsistency might be heterogeneity in the given intervention (dose per time and day, single dose vs. split-dose, placebo formula) and the studied population (blood pressure at baseline, duration of diabetes, use of vasoactive antihypertensive and antidiabetic drugs, sex). Therefore, we aimed to develop a randomized, double-blinded, placebo-controlled cross-over trial to investigate whether cocoa flavanols have an acute impact on blood pressure and vascular reactivity in patients with type 2 diabetes with and without arterial hypertension.

Methods and Analysis: We will include participants in four groups: (i) patients with type 2 diabetes without arterial hypertension, (ii) patients with type 2 diabetes with arterial hypertension and 1 antihypertensive drug, (iii) non-diabetic participants with essential hypertension and 1 antihypertensive drug, and (iv) healthy controls. All participants will complete the same protocol on both testing days, consuming high-flavanol cocoa extract (790 mg flavanols) or placebo. Macrovascular endothelial function (flow-mediated dilation) and blood pressure will be measured before and after capsule ingestion. Forearm muscle vasoreactivity (near-infrared spectroscopy) and brachial artery blood flow (echo-doppler) will be assessed in response to a dynamic handgrip exercise test after capsule ingestion. Data will be analyzed with a random intercept model in mixed models.

Clinical Trial Registration:www.Clinicaltrials.gov, identifier: NCT03722199.

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.

The effects of pilates and flavanol-rich dark chocolate consumption on the total antioxidant capacity, glycemic control and BMI in diabetic females with neuropathy complications

BACKGROUND

Pilates is a type of exercise recommended to diabetic patients due to its health benefits. Dark chocolate is also well known for its antioxidant properties. The purpose of this study has been to compare the effects of regular Pilates and flavanol-rich dark chocolate consumption on the total antioxidant capacity (TAC), fasting blood glucose (FBG) and BMI in diabetic females with peripheral neuropathy complications.

METHODS

36 diabetic patients enrolled in this single-blinded clinical trial. They were randomly allocated to the control (n = 12), Pilates and dark chocolate intake (n = 12), and Pilates and flavanol-free white chocolate (n = 12) groups. Two Pilates groups consumed 25 gr dark or white chocolate 10 min before each Pilates training session, three times per week, for 8 weeks. The control group consumed 25 gr of the same dark chocolate at a pre-determined time 3 times per week, without any regular exercise. Changes in TAC, BMI and FBG were then measured.

RESULTS

Paired t-test analysis showed significant increases in the TAC status, as compared to the baseline in all groups (P ≤ 0.05). However, BMI and FBG reduction were not significant. Covariance (ANCOVA) analysis also showed a significant difference between groups (p < 0.05). Post-hoc Bonferroni test revealed the group that consumed dark chocolate before training had statistically significant increase in the TAC status compared to other groups.

CONCLUSION

The findings indicated that regular flavanol-rich dark chocolate consumption and Pilates significantly increased the TAC status. While FBG was reduced, it was not statistically significant.

Alterations of Lipid Metabolism in Cancer: Implications in Prognosis and Treatment

Cancer remains the second leading cause of mortality worldwide. In the course of this multistage and multifactorial disease, a set of alterations takes place, with genetic and environmental factors modulating tumorigenesis and disease progression. Metabolic alterations of tumors are well-recognized and are considered as one of the hallmarks of cancer. Cancer cells adapt their metabolic competences in order to efficiently supply their novel demands of energy to sustain cell proliferation and metastasis. At present, there is a growing interest in understanding the metabolic switch that occurs during tumorigenesis. Together with the Warburg effect and the increased glutaminolysis, lipid metabolism has emerged as essential for tumor development and progression. Indeed, several investigations have demonstrated the consequences of lipid metabolism alterations in cell migration, invasion, and angiogenesis, three basic steps occurring during metastasis. In addition, obesity and associated metabolic alterations have been shown to augment the risk of cancer and to worsen its prognosis. Consequently, an extensive collection of tumorigenic steps has been shown to be modulated by lipid metabolism, not only affecting the growth of primary tumors, but also mediating progression and metastasis. Besides, key enzymes involved in lipid-metabolic pathways have been associated with cancer survival and have been proposed as prognosis biomarkers of cancer. In this review, we will analyze the impact of obesity and related tumor microenviroment alterations as modifiable risk factors in cancer, focusing on the lipid alterations co-occurring during tumorigenesis. The value of precision technologies and its application to target lipid metabolism in cancer will also be discussed. The degree to which lipid alterations, together with current therapies and intake of specific dietary components, affect risk of cancer is now under investigation, and innovative therapeutic or preventive applications must be explored.

Cocoa colonic phenolic metabolites are related to HDL-cholesterol raising effects and methylxanthine metabolites and insoluble dietary fibre to anti-inflammatory and hypoglycemic effects in humans

BACKGROUND

In many cocoa intervention studies, health outcomes are related to cocoa components without taking into account the bioavailability of the main bioactive components: phenolic compounds and methylxanthines.

METHODS

The present work associates the results of bioavailability and randomised controlled crossover studies in humans carried out with similar cocoa products, so that the main phenol and methylxanthine metabolites observed in plasma and urine are associated to the health effects observed in the chronic studies. We outstand that doses of cocoa and consumption rate used are realistic. In the bioavailability study, a conventional (CC) and a methylxanthine-polyphenol rich (MPC) cocoa product were used, whereas in the chronic study a dietary fibre-rich (DFC) and a polyphenol-rich (PC) product were studied in healthy and cardiovascular risk subjects.

RESULTS AND DISCUSSION

The main phenolic metabolites formed after CC and MPC intake, 5-(4'-hydroxyphenyl)-γ-valerolactone-3'-sulfate, 3'-methyl-epicatechin-5-sulfate, 4-hydroxy-5-(4'-hydroxyphenyl)valeric acid-sulfate, 5-phenyl-γ-valerolactone--sulfate and 5-(4'-hydroxyphenyl)-γ-valerolactone-3'-glucuronide, may contribute to the changes in cholesterol (and indirectly HDL-cholesterol) observed after the regular intake of both DFC and PC, in healthy and cardiovascular risk subjects, whereas 7-methylxanthine (the main cocoa methylxanthine metabolite) and theobromine, together with its content in insoluble dietary fibre, may be responsible for the decrease of IL-1β and hypoglycemic effects observed with DFC. With both phenolic and methylxanthine metabolites a strong dose-response effect was observed.

CONCLUSION

After the regular consumption of both DFC and PC, positive changes were observed in volunteer's lipid profile, which may be related to the long-lasting presence of colonic phenolic metabolites in blood. In contrast, the anti-inflammatory and hypoglycemic effects were only observed with DFC, and these may be related to methylxanthine metabolites, and it is likely that insoluble dietary fibre may have also played a role.

(-)-Epicatechin and the comorbidities of obesity

Obesity has major adverse consequences on human health contributing to the development of, among others, insulin resistance and type 2 diabetes, cardiovascular disease, non-alcoholic fatty liver disease, altered behavior and cognition, and cancer. Changes in dietary habits and lifestyle could contribute to mitigate the development and/or progression of these pathologies. This review will discuss current evidence on the beneficial actions of the flavan-3-ol (-)-epicatechin (EC) on obesity-associated comorbidities. These benefits can be in part explained through EC's capacity to mitigate several common events underlying the development of these pathologies, including: i) high circulating levels of glucose, lipids and endotoxins; ii) chronic systemic inflammation; iii) tissue endoplasmic reticulum and oxidative stress; iv) insulin resistance; v) mitochondria dysfunction and vi) dysbiosis. The currently known underlying mechanisms and cellular targets of EC's beneficial effects are discussed. While, there is limited evidence from human studies supplementing with pure EC, other studies involving cocoa supplementation in humans, pure EC in rodents and in vitro studies, support a potential beneficial action of EC on obesity-associated comorbidities. This evidence also stresses the need of further research in the field, which would contribute to the development of human dietary strategies to mitigate the adverse consequences of obesity.

Flavonoids and type 2 diabetes: Evidence of efficacy in clinical and animal studies and delivery strategies to enhance their therapeutic efficacy

Diabetes mellitus type 2 (T2DM) is a metabolic disorder develops due to the overproduction of free radicals where oxidative stress could contribute it. Possible factors are defective insulin signals, glucose oxidation, and degradation of glycated proteins as well as alteration in glutathione metabolism which induced hyperglycemia. Previous studies revealed a link between T2DM with oxidative stress, inflammation and insulin resistance which are assumed to be regulated by numerous cellular networks such as NF-κB, PI3K/Akt, MAPK, GSK3 and PPARγ. Flavonoids are ubiquitously present in the nature and classified according to their chemical structures for example, flavonols, flavones, flavan-3-ols, anthocyanidins, flavanones, and isoflavones. Flavonoids indicate poor bioavailability which could be improved by employing various nano-delivery systems against the occurrences of T2DM. These bioactive compounds exert versatile anti-diabetic activities via modulating targeted cellular signaling networks, thereby, improving glucose metabolism, α -glycosidase, and glucose transport or aldose reductase by carbohydrate metabolic pathway in pancreatic β-cells, hepatocytes, adipocytes and skeletal myofibres. Moreover, anti-diabetic properties of flavonoids also encounter diabetic related complications. This review article has designed to shed light on the anti-diabetic potential of flavonoids, contribution of oxidative stress, evidence of efficacy in clinical, cellular and animal studies and nano-delivery approaches to enhance their therapeutic efficacy. This article might give some new insights for therapeutic intervention against T2DM in near future.

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.

Targeting Inflammation by Flavonoids: Novel Therapeutic Strategy for Metabolic Disorders

A balanced metabolic profile is essential for normal human physiological activities. Disproportions in nutrition give rise to imbalances in metabolism that are associated with aberrant immune function and an elevated risk for inflammatory-associated disorders. Inflammation is a complex process, and numerous mediators affect inflammation-mediated disorders. The available clinical modalities do not effectively address the underlying diseases but rather relieve the symptoms. Therefore, novel targeted agents have the potential to normalize the metabolic system and, thus, provide meaningful therapy to the underlying disorder. In this connection, polyphenols, the well-known and extensively studied phytochemical moieties, were evaluated for their effective role in the restoration of metabolism via various mechanistic signaling pathways. The various flavonoids that we observed in this comprehensive review interfere with the metabolic events that induce inflammation. The mechanisms via which the polyphenols, in particular flavonoids, act provide a promising treatment option for inflammatory disorders. However, detailed clinical studies of such molecules are required to decide their clinical fate.

Cocoa Flavanols: Natural Agents with Attenuating Effects on Metabolic Syndrome Risk Factors

The interest in cacao flavanols is still growing, as bioactive compounds with potential benefits in the prevention of chronic diseases associated with inflammation, oxidative stress and metabolic disorders. Several analytical methodologies support that the flavanols in cacao-derived products can be absorbed, have bioactive properties, and thus can be responsible for their beneficial effects on human health. However, it must be considered that their biological actions and underlying molecular mechanisms will depend on the concentrations achieved in their target tissues. Based on the antioxidant properties of cacao flavanols, this review focuses on recent advances in research regarding their potential to improve metabolic syndrome risk factors. Additionally, it has included other secondary plant metabolites that have been investigated for their protective effects against metabolic syndrome. Studies using laboratory animals or human subjects represent strong available evidence for biological effects of cacao flavanols. Nevertheless, in vitro studies are also included to provide an overview of these phytochemical mechanisms of action. Further studies are needed to determine if the main cacao flavanols or their metabolites are responsible for the observed health benefits and which are their precise molecular mechanisms.

Potential role of phytochemicals in metabolic syndrome prevention and therapy

Metabolic syndrome (MetS) is a set of cardiovascular risk factors which severely increases the risk of type II diabetes, renal disease and cardiovascular disease. Over the last decades, the role of dietary bioactive substances in features of MetS has been extensively investigated. Due to their multiple properties, these plant-derived natural compounds have demonstrated to provide positive effects in obesity, diabetes, renal and in cardiovascular disease. Catechins of green tea and caffeine reduce body mass index and waist circumference. Catechins, anthocyanins and proanthocyanidins of cocoa reduce blood pressure and blood glucose. Curcumin and silymarin exert hepatoprotective effects. Monacolins of red yeast rice are effective cholesterol-lowering agents. However, inconsistent or conflicting results have been found in clinical trials when other promising compounds in vitro or in animal studies, such as policosanol, curcumin or silymarin, were used. Low oral bioavailability of substances, ineffective dosages, inadequate treatment duration and insufficient statistical approach may explain the lack of effectiveness observed in some human studies. Further clinical studies are needed to better understand the role of bioactive compounds in the prevention and management of MetS.

(-)-Epicatechin in the control of glucose homeostasis: Involvement of redox-regulated mechanisms

Emerging evidence supports a beneficial action of the flavan-3-ol (-)-epicatechin (EC) on insulin sensitivity and potential impact on the development/progression of type 2 diabetes (T2D). In humans, supplementation with EC-rich foods, extracts, and pure EC improves insulin sensitivity and glucose tolerance in normal weight, overweight, obese and T2D individuals. These effects of EC are also observed in rodent models of diet-induced obesity and T2D. The events involved in the development of insulin resistance and T2D are multiple and interrelated. EC has been shown to inhibit inflammation, oxidative and endoplasmic reticulum stress, to modulate mitochondrial biogenesis and function, and to regulate events in the gastrointestinal tract and the pancreas that impact glucose homeostasis. A downregulation of oxidant production, particularly through direct inhibition or suppression of NADPH oxidase expression, and of redox sensitive signals (NF-κB, JNK1/2) that inhibit the insulin pathway, appear to be central to the beneficial actions of EC on insulin sensitivity. Overall, EC seems to have a positive role in the regulation of glucose homeostasis, however definitive answers on its importance for the management of T2D will depend on further clinical and mechanistic studies.

The Effects of Soy Protein and Cocoa With or Without Isoflavones on Glycemic Control in Type 2 Diabetes. A Double-Blind, Randomized, Placebo-Controlled Study

Objective: Soy and cocoa have been suggested to be beneficial for diabetes. The aim of this study was to identify the effects of soy protein, isoflavones, and cocoa on glycemic control parameters. Research design and methods: The study was a parallel, double-blind, placebo-controlled study where patients with diet or metformin controlled type 2 diabetes were randomized to, casein soy protein with or without isoflavones (SPI, SP), and with or without cocoa (SPIC, SPC) arms for an 8 week period. Glycemic control and cardiovascular risk factors were assessed prior to and after the completion of the dietary intervention. Sixty participants completed the study. Results: Soy protein improved HbA1c compared to casein (p < 0.05). The addition of isoflavones improved indices of insulin resistance and LDL [delta QUICKIE (SPI: -0.12 ± 0.04 vs. SP: 0.03 ± 0.06, p = 0.03); delta LDL (-0.27 ± 0.41 vs. 0.22 ± 0.43, p = 0.02); percentage change in HOMA (31.02 ± 54.75 vs. -14.42 ± 27.07, p = 0.02); percentage change in QUICKIE (-3.89 ± 7.07 vs. 6.11 ± 10.54, p = 0.01)]. However, the addition of cocoa provided no benefit with or without isoflavones. Summary: Soy protein had intrinsic activity on glycemic control compared to casein. Isoflavones improved both insulin resistance and LDL, but cocoa did not have added benefit on these indices. Clinical Trial Registration: www.ClinicalTrials.gov, identifier NCT01754662.

Regular Intake of a Usual Serving Size of Flavanol-Rich Cocoa Powder Does Not Affect Cardiometabolic Parameters in Stably Treated Patients with Type 2 Diabetes and Hypertension-A Double-Blinded, Randomized, Placebo-Controlled Trial

Regular cocoa consumption has been shown to improve blood pressure (BP), insulin sensitivity, and lipid levels in patients with type 2 diabetes (T2D), using up to 100 g of chocolate or 54 g of cocoa. These effects, attributed to cocoa flavanols, would be beneficial for patients with T2D if they could be achieved by a usual serving size of flavanol-rich cocoa. Forty-two hypertensive patients with T2D (stable pharmacological treatment, with good adjustment for glucose metabolism, lipids, and BP) ingested capsules with 2.5 g/day of a flavanol-rich cocoa or cocoa-free capsules for 12 weeks in a double-blinded, randomized, placebo-controlled study with parallel group design. Participants had to maintain diet, lifestyle, and medication. Before and after intervention, fasting blood samples were collected; BP and nutritional status were investigated. Cocoa treatment did not affect BP, nor glucose metabolism (glucose, HbA_1c, insulin, HOMA-IR) and lipids (triglycerides, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol). Body weight, fat mass, and nutrient supply remained unchanged. Changes in the placebo group did not occur. Regular intake of a usual serving size of flavanol-rich cocoa does not improve cardiometabolic parameters in stably treated patients with T2D and hypertension. As the medication modulates partly the same targets as cocoa flavanols, future studies should focus on the preventive effect of cocoa against diabetes and other cardiometabolic diseases in individuals with preexisting abnormalities that do not require any pharmacological treatment.

Cocoa Pod Husk Pectin Intended as a Pharmaceutical Excipient Has No Adverse Effects on Haematological Parameters in Sprague Dawley Rats

Natural polymer research has recently become the focus of intensive research in the quest for new enabling excipients for novel drugs in pharmaceutical formulation for optimal treatment outcomes. Evaluations of some excipients have shown deleterious haematological effects of varying extents on the safety profile of these excipients. A 90-day subchronic toxicity study was conducted to evaluate the influence of cocoa pod husk (CPH) pectin on indicators for haematotoxicity. Male and female Sprague Dawley rats (SDRs) were fed with CPH pectin in doses up to 71.4 mg/kg. The effects of CPH pectin on the haematological indices, direct and total bilirubin, and the spleen were determined. The results indicated that CPH pectin did not induce any untoward toxic effects on the haematological indices, bilirubin levels, and the spleen. There were, however, elevations in MCV at day 30, which was not sustained after the 90 days. The data obtained from this study did not reveal any remarkable findings of toxicological relevance to the haematopoietic system.

Pharmacological potential of methylxanthines: Retrospective analysis and future expectations

Methylated xanthines (methylxanthines) are available from a significant number of different botanical species. They are ordinarily included in daily diet, in many extremely common beverages and foods. Caffeine, theophylline and theobromine are the main methylxanthines available from natural sources. The supposedly relatively low toxicity of methylxanthines, combined with the many beneficial effects that have been attributed to these compounds through time, generated a justified attention and a very prolific ground for dedicated scientific reports. Methylxanthines have been widely used as therapeutical tools, in an intriguing range of medicinal scopes. In fact, methylxanthines have been/were medically used as Central Nervous System stimulants, bronchodilators, coronary dilators, diuretics and anti-cancer adjuvant treatments. Other than these applications, methylxanthines have also been hinted to hold other beneficial health effects, namely regarding neurodegenerative diseases, cardioprotection, diabetes and fertility. However, it seems now consensual that toxicity concerns related to methylxanthine consumption and/or therapeutic use should not be dismissed. Taking all the knowledge and expectations on the potential of methylxanthines into account, we propose a systematic look at the past and future of methylxanthine pharmacologic applications, discussing all the promise and anticipating possible constraints. Anyways, methylxanthines will still substantiate considerable meaningful research and discussion for years to come.

Nutrition epidemiology of flavan-3-ols: The known unknowns

Nutritional epidemiology has an important role, as it can provide long-term data from large populations and does not rely on surrogate markers for morbidity/mortality. Meaningful interpretation and applications of outcomes from epidemiological studies depend on the accurate assessment of dietary intake, which is currently mainly based on a combination of self-reporting and food composition data. Flavan-3-ols are a group of bioactives (non-essential dietary components with significant impact on health) that is a possible candidate for the development of dietary recommendations. The breadth of data available on their effect on health also provides the basis for investigating the suitability of the methods currently used in nutritional epidemiology to assess the health effects of bioactives. The outcomes of this assessment demonstrate that the limitations of currently used methods make it virtually impossible to estimate intake accurately from self-reported dietary data. This is due to the limitations of self-reporting, especially from food-frequency questionnaires, and the inability of currently used methods to deal with the high variability of food composition. Indeed, the estimated intake of flavan-3-ols, can only be interpreted as a marker of specific dietary patterns, but not as the actual intake amount. The interpretation of results from such studies are fraught with serious limitations, especially for establishing associations between intake and health and the development of dietary recommendations. Alternative assessment not affected by these limitations, such as biomarkers, are required to overcome these limitations. The development of nutritional biomarkers is therefore crucial to investigate the health effect of bioactives.

Effects of Cocoa Antioxidants in Type 2 Diabetes Mellitus

Type 2 Diabetes mellitus (T2D) is the most common form of diabetes and one of the most common chronic diseases. Control of hyperglycaemia by hypoglycaemic drugs is insufficient in for patients and nutritional approaches are currently being explored. Natural dietary compounds such as flavonoids, abundant in fruits and vegetables, have received broad attention because of their potential capacity to act as anti-diabetic agents. Especially cocoa flavonoids have been proved to ameliorate important hallmarks of T2D. In this review, an update of the most relevant reports published during the last decade in cell culture, animal models and human studies is presented. Most results support an anti-diabetic effect of cocoa flavonoids by enhancing insulin secretion, improving insulin sensitivity in peripheral tissues, exerting a lipid-lowering effect and preventing the oxidative and inflammatory damages associated to the disease. While it could be suggested that daily consumption of flavanols from cocoa or dark chocolate would constitute a potential preventive tool useful for the nutritional management of T2D, this recommendation should be cautious since most of commercially available soluble cocoa products or chocolates contain low amount of flavanols and are rich in sugar and calories that may aggravate glycaemic control in T2D patients.

Dietary polyphenols for atherosclerosis: A comprehensive review and future perspectives

Atherosclerosis is one of the most prevalent reasons for premature death in adults. Despite the several conventional drugs in the market; many patients are not completely treated. Here we comprehensively review current clinical evidence regarding the efficacy of dietary polyphenols in atherosclerosis and related complications. PubMed, Cochrane library and Scopus were searched from inception until August 2016 to obtain clinical trials in which polyphenols were evaluated in cardiovascular parameters related to atherosclerosis. From total of 13031 results, 49 clinical trials were finally included. Tyrosol derivatives from virgin olive oil, catechins and theaflavins from green and black tea, cocoa polyphenols, and red grape resveratrol, as well as anthocyanins were the most studied polyphenolic compounds which could regulate lipid profile, inflammation and oxidative stress, blood pressure, endothelial function, and cell adhesion molecules. The most important limitations of the included trials were small sample size, short follow up, and unqualified methodology. Future well-designed clinical trials are necessary to provide better level of evidence for clinical decision making.

Protective effects of tea, red wine and cocoa in diabetes. Evidences from human studies

Prevention of diabetes through the diet has recently received an increasing interest, and polyphenolic compounds, such as flavanols, have become important potential chemopreventive natural agents due to their proved benefits on health, with low toxicity and cost. Tea, red wine and cocoa are good sources of flavanols and these highly consumed foods might contribute to prevent diabetes. In this regard, there is increasing evidence for a protective effect of tea, red wine and cocoa consumption against this disorder. This review summarizes the available epidemiological and interventional human studies providing evidence for and against this effect. Overall observational data suggest a benefit, but results are still equivocal and likely confounded by lifestyle and background dietary factors. The weight of data indicate favourable effects on diabetes risk factors for tea, red wine and cocoa intake, and a number of plausible mechanisms have been elucidated in human studies. However, despite the growing evidence it remains uncertain whether tea, red wine and cocoa consumption should be recommended to the general population or to patients as a strategy to reduce the risk of diabetes.

Cocoa, Blood Pressure, and Vascular Function

Cardiovascular disease (CVD) represents the most common cause of death worldwide. The consumption of natural polyphenol-rich foods, and cocoa in particular, has been related to a reduced risk of CVD, including coronary heart disease and stroke. Intervention studies strongly suggest that cocoa exerts a beneficial impact on cardiovascular health, through the reduction of blood pressure (BP), improvement of vascular function, modulation of lipid and glucose metabolism, and reduction of platelet aggregation. These potentially beneficial effects have been shown in healthy subjects as well as in patients with risk factors (arterial hypertension, diabetes, and smoking) or established CVD (coronary heart disease or heart failure). Several potential mechanisms are supposed to be responsible for the positive effect of cocoa; among them activation of nitric oxide (NO) synthase, increased bioavailability of NO as well as antioxidant, and anti-inflammatory properties. It is the aim of this review to summarize the findings of cocoa and chocolate on BP and vascular function.

A Systematic Review and Meta-Analysis of the Effects of Flavanol-Containing Tea, Cocoa and Apple Products on Body Composition and Blood Lipids: Exploring the Factors Responsible for Variability in Their Efficacy

Several randomized controlled trials (RCTs) and meta-analyses support the benefits of flavanols on cardiometabolic health, but the factors affecting variability in the responses to these compounds have not been properly assessed. The objectives of this meta-analysis were to systematically collect the RCTs-based-evidence of the effects of flavanol-containing tea, cocoa and apple products on selected biomarkers of cardiometabolic risk and to explore the influence of various factors on the variability in the responses to the consumption of these products. A total of 120 RCTs were selected. Despite a high heterogeneity, the intake of the flavanol-containing products was associated using a random model with changes (reported as standardized difference in means (SDM)) in body mass index (−0.15, p < 0.001), waist circumference (−0.29, p < 0.001), total-cholesterol (−0.21, p < 0.001), LDL-cholesterol (−0.23, p < 0.001), and triacylglycerides (−0.11, p = 0.027), and with an increase of HDL-cholesterol (0.15, p = 0.005). Through subgroup analyses, we showed the influence of baseline-BMI, sex, source/form of administration, medication and country of investigation on some of the outcome measures and suggest that flavanols may be more effective in specific subgroups such as those with a BMI ≥ 25.0 kg/m², non-medicated individuals or by specifically using tea products. This meta-analysis provides the first robust evidence of the effects induced by the consumption of flavanol-containing tea, cocoa and apple products on weight and lipid biomarkers and shows the influence of various factors that can affect their bioefficacy in humans. Of note, some of these effects are quantitatively comparable to those produced by drugs, life-style changes or other natural products. Further, RCTs in well-characterized populations are required to fully comprehend the factors affecting inter-individual responses to flavanol and thereby improve flavanols efficacy in the prevention of cardiometabolic disorders.

Chronic administration of apple polyphenols ameliorates hyperglycaemia in high-normal and borderline subjects: A randomised, placebo-controlled trial

AIMS

We previously reported that apple polyphenols (AP) and their major active components, procyanidins, had beneficial effects on glucose homeostasis and diabetes in diabetic ob/ob mice. The present study was performed to evaluate the effects of chronic AP administration on glucose tolerance in high-normal and borderline human subjects.

METHODS

Subjects (n=65) with a fasting plasma glucose (FPG) level of 100-125mg/dL determined during a recent health check-up were randomised to receive tablets containing AP (600mg/day) or placebo tablets for 12weeks in a double-blinded, placebo-controlled clinical trial. The primary outcome was insulin resistance, assessed using a 75g oral glucose tolerance test (OGTT).

RESULTS

The 12-week chronic administration of AP significantly reduced the increase in glucose at 30-min post-75g OGTT (OGTT_{30-min glucose}) value, compared to the placebo regimen. Furthermore, in a subgroup of the high-normal (FPG value, 100-109mg/dL; 2-h post-75g OGTT glucose (OGTT_{2-h glucose}) value, <140mg/dL) and borderline (FPG value, 110-125mg/dL; OGTT_{2-h glucose} value, <140mg/dL and FPG value, <126mg/dL; OGTT_{2-h glucose} value, 140-199mg/dL) subjects, OGTT_{30-min glucose} value in the AP group (164.0±7.4mg/dL) was significantly lower than that of the placebo group (194.7±10.4mg/dL, p<0.05). No significant changes in the other lipid parameters and cytokine levels were observed.

CONCLUSIONS

Chronic AP administration significantly improved impaired glucose tolerance in high-normal and borderline subjects. Larger and/or longer-term scale human studies are required to confirm the potential glucose homeostasis of AP.

Cocoa and Dark Chocolate Polyphenols: From Biology to Clinical Applications

It is well known that cocoa and dark chocolate possess polyphenols as major constituents whose dietary consumption has been associated to beneficial effects. In fact, cocoa and dark chocolate polyphenols exert antioxidant and anti-inflammatory activities switching on some important signaling pathways such as toll-like receptor 4/nuclear factor κB/signal transducer and activator of transcription. In particular, cocoa polyphenols induce release of nitric oxide (NO) through activation of endothelial NO synthase which, in turn, accounts for vasodilation and cardioprotective effects. In the light of the above described properties, a number of clinical trials based on the consumption of cocoa and dark chocolate have been conducted in healthy subjects as well as in different categories of patients, such as those affected by cardiovascular, neurological, intestinal, and metabolic pathologies. Even if data are not always concordant, modifications of biomarkers of disease are frequently associated to improvement of clinical manifestations. Quite interestingly, following cocoa and dark chocolate ingestion, cocoa polyphenols also modulate intestinal microbiota, thus leading to the growth of bacteria that trigger a tolerogenic anti-inflammatory pathway in the host. Finally, many evidences encourage the consumption of cocoa and dark chocolate by aged people for the recovery of the neurovascular unit.

Xanthohumol, a hop-derived prenylated flavonoid, promotes macrophage reverse cholesterol transport

Xanthohumol, a prominent prenyl flavonoid from the hop plant (Humulus lupulus L.), is suggested to be antiatherogenic since it reportedly increases high-density lipoprotein (HDL) cholesterol levels. It is not clear whether xanthohumol promotes reverse cholesterol transport (RCT), the most important antiatherogenic property of HDL; therefore, we investigated the effects of xanthohumol on macrophage-to-feces RCT using a hamster model as a CETP-expressing species. In vivo RCT experiments showed that xanthohumol significantly increased fecal appearance of the tracer derived from intraperitoneally injected [³H]-cholesterol-labeled macrophages. Ex vivo experiments were then employed to investigate the detailed mechanism by which xanthohumol enhanced RCT. Cholesterol efflux capacity from macrophages was 1.5-fold higher in xanthohumol-fed hamsters compared with the control group. In addition, protein expression and lecithin-cholesterol acyltransferase activity in the HDL fraction were significantly higher in xanthohumol-fed hamsters compared with the control, suggesting that xanthohumol promoted HDL maturation. Hepatic transcript analysis revealed that xanthohumol increased mRNA expression of abcg8 and cyp7a1. In addition, protein expressions of liver X receptor α and bile pump export protein were increased in the liver by xanthohumol administration when compared with the control, implying that it stimulated bile acid synthesis and cholesterol excretion to feces. In conclusion, our data demonstrate that xanthohumol improves RCT in vivo through cholesterol efflux from macrophages and excretion to feces, leading to antiatherosclerosis effects. It remains to be elucidated whether enhancement of RCT by xanthohumol could prove valuable in humans.

Nutritional intervention and impact of polyphenol on glycohemoglobin (HbA1c) in non-diabetic and type 2 diabetic subjects: Systematic review and meta-analysis

Polyphenols have been extensively studied for their antioxidant and anti-inflammatory properties. Recently, their antiglycative actions by oxidative stress modulation have been linked to the prevention of diabetes and associated complications. This article assesses the evidence for polyphenol interventions on glycohemoglobin (HbA1c) in non-diabetic, pre-diabetic, and type 2 diabetes mellitus (T2DM) subjects. A systematic review of polyphenols' clinical trials on HbA1c in humans was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis. Thirty-six controlled randomized trials with HbA1c values were included. Polyphenols (extracts, supplements, and foods) were supplemented (28 mg to 1.5 g) for 0.7 to 12 months. Combining all subjects (n = 1954, mean baseline HbA1c = 7.03%, 53 mmol/mol), polyphenol supplementation significantly (P < 0.001) lowered HbA1c% by -0.53 ± 0.12 units (-5.79 ± 0.13 mmol/mol). This reduction was significant (P < 0.001) in T2DM subjects, specifically (n = 1426, mean baseline HbA1c = 7.44%, 58 mmol/mol), with HbA1c% lowered by -0.21 ± 0.04 units (-2.29 ± 0.4 mmol/mol). Polyphenol supplementation had no significant effect (P > 0.21) in the non-diabetic (n = 258, mean baseline HbA1c = 5.47%, 36 mmol/mol) and the pre-diabetic subjects (n = 270, mean baseline HbA1c = 6.06%, 43 mmol/mol) strata: -0.39 ± 0.27 HbA1c% units (-4.3 ± 0.3 mmol/mol), and -0.38 ± 0.31 units (-4.2 ± 0.31 mmol/mol), respectively. In conclusion, polyphenols can successfully reduce HbA1c in T2DM without any intervention at glycemia, and could contribute to the prevention of diabetes complications.

Cocoa Flavanol Intake and Biomarkers for Cardiometabolic Health: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

BACKGROUND

Cocoa flavanols may improve cardiometabolic health. Evidence from small short-term randomized clinical trials (RCTs) remains inconsistent, and large long-term RCTs testing the efficacy of cocoa flavanols are still lacking.

OBJECTIVE

We performed a systematic review and meta-analysis of RCTs to quantify the effect of cocoa flavanol intake on cardiometabolic biomarkers.

METHODS

We searched PubMed, Web of Science, and the Cochrane Library for RCTs that evaluated the effects of cocoa flavanols on biomarkers relevant to vascular disease pathways among adults. Data were extracted following a standardized protocol. We used DerSimonian and Laird random-effect models to compute the weighted mean differences (WMDs) and 95% CIs. We also examined potential modification by intervention duration, design, age, sex, comorbidities, and the form and amount of cocoa flavanol intake.

RESULTS

We included 19 RCTs that comprised 1131 participants, and the number of studies for a specific biomarker varied. The amount of cocoa flavanols ranged from 166 to 2110 mg/d, and intervention duration ranged from 2 to 52 wk. Cocoa flavanol intake significantly improved insulin sensitivity and lipid profile. The WMDs between treatment and placebo were -0.10 mmol/L (95% CI: -0.16, -0.04 mmol/L) for total triglycerides, 0.06 mmol/L (95% CI: 0.02, 0.09 mmol/L) for HDL cholesterol, -2.33 μIU/mL (95% CI: -3.47, -1.19 μIU/mL) for fasting insulin, -0.93 (95% CI: -1.31, -0.55) for the homeostatic model assessment of insulin resistance, 0.03 (95% CI: 0.01, 0.05) for the quantitative insulin sensitivity check index, 2.54 (95% CI: 0.63, 4.44) for the insulin sensitivity index, -0.83 mg/dL (95% CI: -0.88, -0.77 mg/dL) for C-reactive protein, and 85.6 ng/mL (95% CI: 16.0, 155 ng/mL) for vascular cell adhesion molecule 1. No significant associations were found for other biomarkers. None of the modifiers seemed to qualitatively modify the effects of cocoa flavanol intake.

CONCLUSIONS

Our study suggests that cocoa flavanol intake has favorable effects on select cardiometabolic biomarkers among adults. These findings support the need for large long-term RCTs to assess whether cocoa flavanol intake reduces the risk of diabetes and cardiovascular events.

Effect of Flavonoids on Oxidative Stress and Inflammation in Adults at Risk of Cardiovascular Disease: A Systematic Review

Oxidative stress (OS) and inflammatory processes initiate the first stage of cardiovascular disease (CVD). Flavonoid consumption has been related to significantly improved flow-mediated dilation and blood pressure. Antioxidant and anti-inflammatory mechanisms are thought to be involved. The effect of flavonoids on markers of oxidative stress and inflammation, in at risk individuals is yet to be reviewed. Systematic literature searches were conducted in MEDLINE, Cochrane Library, CINAHL and SCOPUS databases. Randomised controlled trials in a Western country providing a food-based flavonoid intervention to participants with one or two modifiable risk factors for CVD measuring a marker of OS and/or inflammation, were included. Reference lists were hand-searched. The Cochrane Collaboration Risk of Bias Tool was used to assess study quality. The search strategy retrieved 1248 articles. Nineteen articles meeting the inclusion criteria were reviewed. Eight studies were considered at low risk of bias. Cocoa flavonoids provided to Type 2 diabetics and olive oil flavonoids to mildly-hypertensive women reduced OS and inflammation. Other food sources had weaker effects. No consistent effect on OS and inflammation across patients with varied CVD risk factors was observed. Study heterogeneity posed a challenge for inter-study comparisons. Rigorously designed studies will assist in determining the effectiveness of flavonoid interventions for reducing OS and inflammation in patients at risk of CVD.

Structure-Bioactivity Relationships of Methylxanthines: Trying to Make Sense of All the Promises and the Drawbacks

Methylxanthines are a group of phytochemicals derived from the purine base xanthine and obtained from plant secondary metabolism. They are unobtrusively included in daily diet in common products as coffee, tea, energetic drinks, or chocolate. Caffeine is by far the most studied methylxanthine either in animal or epidemiologic studies. Theophylline and theobromine are other relevant methylxanthines also commonly available in the aforementioned sources. There are many disseminated myths about methylxanthines but there is increased scientific knowledge to discuss all the controversy and promise shown by these intriguing phytochemicals. In fact, many beneficial physiologic outcomes have been suggested for methylxanthines in areas as important and diverse as neurodegenerative and respiratory diseases, diabetes or cancer. However, there have always been toxicity concerns with methylxanthine (over)consumption and pharmacologic applications. Herein, we explore the structure-bioactivity relationships to bring light those enumerated effects. The potential shown by methylxanthines in such a wide range of conditions should substantiate many other scientific endeavors that may highlight their adequacy as adjuvant therapy agents and may contribute to the advent of functional foods. Newly designed targeted molecules based on methylxanthine structure may originate more specific and effective outcomes.