Does chocolate reduce blood pressure? A meta-analysis

A single oral dose of flavan-3-ols enhances energy expenditure by sympathetic nerve stimulation in mice

Numerous clinical studies have found that ingestion of chocolate reduces the risk of metabolic syndrome, however, the mechanisms were remain unclear. We have reported that a single dose of a flavan-3-ol fraction derived from cocoa (FL) enhanced energy expenditure (EE) and increased the mRNA expression levels of uncoupling proteins (UCPs) and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α), and the protein level of phosphorylated AMP-activated protein kinase (AMPK)α in tissues, along with plasma adrenaline level. In the present study, we examined whether the EE enhancing activity of FL is mediated by adrenergic effect using several adrenalin receptor (AR) blockers. In the first study, mice were butoxamine, as β2AR blocker, with vehicle or 10mg/kg FL orally. We found that pretreatment with butoxamine prevented the increases of EE, the mRNA expression of UCP-3, and phosphorylated AMPKα that were induced in the gastrocnemius muscle of mice by 10mg/kg FL. Secondly, mice were given SR52930, as β3AR blocker. Pretreatment with SR52930 prevented the increases of EE, the mRNA expression of UCP-3, and phosphorylated AMPKα that were induced in the gastrocnemius muscle of mice by 10mg/kg FL. Pretreatment with a combination of both blockers also reduced the increments in mRNA expression levels of UCPs and PGC-1α, however, phosphorylated AMPKα in skeletal muscle was rather increased. These results suggest that the ability of a single oral dose of FL to enhance metabolic activity is mediated by sympathetic nerve system (SNS).

Diabetes and chocolate: friend or foe?

Polyphenols and other compounds found in cocoa and chocolate have therapeutic potential in the management of diabetes in humans. Polyphenol benefits have been proposed supported by in vitro studies, animal work, and clinical trials, which have been conducted mostly in healthy volunteers. The energy-dense formulations of many cocoa and chocolate products, which can be up to 50% sugar by weight, have given the perception that chocolate may be harmful through its contribution to obesity. A review of both clinical trial databases and published literature yielded 15 registered trials and 7 published studies. The published data interventions reported are diverse and vary widely in quality, including poor selection of control products or inadequate blinding procedures. There are also inconsistencies in reporting of data with limited information on the effect of cocoa and chocolate supplementation on weight and glycemic control despite the potential benefits reported with respect to the cardiovascular risk factors of endothelial function and lipids. More studies are required powered for primary clinical outcomes together with the development of standardized product formulations that optimize the dose of polyphenols within a palatable and energy-restricted product.

Cocoa, blood pressure, and cardiovascular health

High blood pressure is an important risk factor for cardiovascular disease and cardiovascular events worldwide. Clinical and epidemiological studies suggest that cocoa-rich products reduce the risk of cardiovascular disease. According to this, cocoa has a high content in polyphenols, especially flavanols. Flavanols have been described to exert favorable effects on endothelium-derived vasodilation via the stimulation of nitric oxide-synthase, the increased availability of l-arginine, and the decreased degradation of NO. Cocoa may also have a beneficial effect by protecting against oxidative stress alterations and via decreased platelet aggregation, decreased lipid oxidation, and insulin resistance. These effects are associated with a decrease of blood pressure and a favorable trend toward a reduction in cardiovascular events and strokes. Previous meta-analyses have shown that cocoa-rich foods may reduce blood pressure. Long-term trials investigating the effect of cocoa products are needed to determine whether or not blood pressure is reduced on a chronic basis by daily ingestion of cocoa. Furthermore, long-term trials investigating the effect of cocoa on clinical outcomes are also needed to assess whether cocoa has an effect on cardiovascular events. A 3 mmHg systolic blood pressure reduction has been estimated to decrease the risk of cardiovascular and all-cause mortality. This paper summarizes new findings concerning cocoa effects on blood pressure and cardiovascular health, focusing on putative mechanisms of action and "nutraceutical " viewpoints.

Chocolate Consumption and Risk of Atrial Fibrillation (from the Physicians' Health Study)

Chocolate consumption has been shown to protect against various cardiovascular end points; however, little is known about the association between chocolate consumption and incident atrial fibrillation (AF). Therefore, we prospectively examined the association between chocolate consumption and incident AF in a cohort of 18,819 US male physicians. Chocolate consumption was ascertained from 1999 to 2002 through a self-administered food frequency questionnaire. Incident AF was ascertained through yearly follow-up questionnaires. Cox regression was used to estimate relative risks of AF. The average age at baseline was 66 years (±9.1). During a mean follow-up of 9.0 years (±3.0), 2,092 cases of AF occurred. Using <1 per month of chocolate consumption as the reference group, multivariable adjusted hazard ratios (95% confidence interval) for AF were 1.04 (0.93 to 1.18), 1.10 (0.96 to 1.25), 1.14 (0.99 to 1.31), and 1.05 (0.89 to 1.25) for chocolate intake of 1 to 3 per month and 1, 2 to 4, and ≥5 per week (p for trend 0.25), respectively. In a secondary analysis, there was no evidence of effect modification by adiposity (p interaction = 0.71) or age (p interaction = 0.26). In conclusion, our data did not support an association between chocolate consumption and risk of AF in US male physicians.

The acute and sub-chronic effects of cocoa flavanols on mood, cognitive and cardiovascular health in young healthy adults: a randomized, controlled trial

Cocoa supplementation has been associated with benefits to cardiovascular health. However, cocoa's effects on cognition are less clear. A randomized, placebo-controlled, double-blind clinical trial (n = 40, age M = 24.13 years, SD = 4.47 years) was conducted to investigate the effects of both acute (same-day) and sub-chronic (daily for four-weeks) 250 mg cocoa supplementation on mood and mental fatigue, cognitive performance and cardiovascular functioning in young, healthy adults. Assessment involved repeated 10-min cycles of the Cognitive Demand Battery (CDB) encompassing two serial subtraction tasks (Serial Threes and Sevens), a Rapid Visual Information Processing task, and a mental fatigue scale over the course of half an hour. The Swinburne University Computerized Cognitive Assessment Battery (SUCCAB) was also completed to evaluate cognition. Cardiovascular function included measuring both peripheral and central blood pressure and cerebral blood flow. At the acute time point, consumption of cocoa significantly improved self-reported mental fatigue and performance on the Serial Sevens task in cycle one of the CDB. No other significant effects were found. This trial was registered with the Australian and New Zealand Clinical Trial Registry (Trial ID: ACTRN12613000626763). Accessible via http://www.anzctr.org.au/TrialSearch.aspx?searchTxt=ACTRN12613000626763&ddlSearch=Registered.

Effects of the pure flavonoids epicatechin and quercetin on vascular function and cardiometabolic health: a randomized, double-blind, placebo-controlled, crossover trial

BACKGROUND

Prospective cohort studies showed inverse associations between the intake of flavonoid-rich foods (cocoa and tea) and cardiovascular disease (CVD). Intervention studies showed protective effects on intermediate markers of CVD. This may be due to the protective effects of the flavonoids epicatechin (in cocoa and tea) and quercetin (in tea).

OBJECTIVE

We investigated the effects of supplementation of pure epicatechin and quercetin on vascular function and cardiometabolic health.

DESIGN

Thirty-seven apparently healthy men and women aged 40-80 y with a systolic blood pressure (BP) between 125 and 160 mm Hg at screening were enrolled in a randomized, double-blind, placebo-controlled, crossover trial. CVD risk factors were measured before and after 4 wk of daily flavonoid supplementation. Participants received (-)-epicatechin (100 mg/d), quercetin-3-glucoside (160 mg/d), or placebo capsules for 4 wk in random order. The primary outcome was the change in flow-mediated dilation from pre- to postintervention. Secondary outcomes included other markers of CVD risk and vascular function.

RESULTS

Epicatechin supplementation did not change flow-mediated dilation significantly (1.1% absolute; 95% CI: -0.1%, 2.3%; P = 0.07). Epicatechin supplementation improved fasting plasma insulin (Δ insulin: -1.46 mU/L; 95% CI: -2.74, -0.18 mU/L; P = 0.03) and insulin resistance (Δ homeostasis model assessment of insulin resistance: -0.38; 95% CI: -0.74, -0.01; P = 0.04) and had no effect on fasting plasma glucose. Epicatechin did not change BP (office BP and 24-h ambulatory BP), arterial stiffness, nitric oxide, endothelin 1, or blood lipid profile. Quercetin-3-glucoside supplementation had no effect on flow-mediated dilation, insulin resistance, or other CVD risk factors.

CONCLUSIONS

Our results suggest that epicatechin may in part contribute to the cardioprotective effects of cocoa and tea by improving insulin resistance. It is unlikely that quercetin plays an important role in the cardioprotective effects of tea. This study was registered at clinicaltrials.gov as NCT01691404.

Chocolate and health-related quality of life: a prospective study

Background

Chocolate consumption has been associated with a short-term reduction in blood pressure and cholesterol, and improvement of insulin sensitivity; however, participants could not be aware of presenting hypertension or hypercholesterolemia. Moreover, the effect of chocolate on mental health is uncertain. This study assessed the association of regular chocolate consumption with the physical (PCS) and mental (MCS) components of health-related quality of life (HRQL).

Materials and methods

We analyzed data from a cohort of 4599 individuals recruited in 2008–2010 and followed-up once prospectively to January 2013 (follow-up mean: 3.5 years). Regular chocolate consumption was assessed at baseline with a validated diet history. HRQL was assessed with the SF-12 v.2 at baseline and at follow-up. Analyses were performed with linear regression and adjusted for the main confounders, including HRQL at baseline.

Results

At baseline, 72% of the study participants did not consume chocolate, 11% consumed ≤10 g/day and 17% >10 g/day. Chocolate consumption at baseline did not show an association with PCS and MCS of the SF-12 measured three years later. Compared to those who did not consume chocolate, the PCS scores were similar in those who consumed ≤10g/day (beta: -0.07; 95% confidence interval (95% CI): -0.94 to 0.80) and in those who consumed >10g/day (beta: 0.02; 95% CI:-0.71 to 0.75); corresponding figures for the MCS were 0.29; 95% CI: -0.67 to 1.26, and -0.57; 95%CI: -1.37 to 0.23. Similar results were found for sex, regardless of obesity, hypertension, hypercholesterolemia, diabetes or depression.

Conclusions

No evidence was found of an association between chocolate intake and the physical or mental components of HRQL.

Short term effects of cocoa consumption on blood pressure

Hypertension, defined as diastolic pressure ≥ 90 mmHg and systolic pressure ≥ 140 mmHg, is a major cause of morbidity and mortality among black populations globally. Several studies have shown that prolonged consumption of cocoa or cocoa containing products leads to decreased blood pressure (BP) in hypertensives. In this study, we investigated the flavonoid content of the top selling cocoa/cocoa based products in Trinidad and Tobago and attempted to determine if consumption of cocoa had any immediate impact on blood pressure levels. The flavonoid content of three 100% cocoa powder products and four cocoa based formulas was measured using a modified Folin-Ciocalteu procedure. The brand with the highest flavonoid content, 372 gallic acid equivalents, was selected to evaluate the short-term impact of cocoa consumption on blood pressure. Thirty-six participants comprising nineteen hypertensives and seventeen persons with normal blood pressure had their blood pressure recorded on three separate days using ambulatory blood pressure monitors; the blood pressure was recorded every half hour for eight hours. On the first day, the participants received no intervention but on the second and third days, they received either the intervention (5 g cocoa in 125 ml water) or a placebo, in any order. Statistical analysis conducted using t-test statistic and a 95% confidence interval revealed that whether participants regularly took antihypertensive medication or not, a single intervention of cocoa induced decreases in both the diastolic and systolic BPs that were significant (p = 0.0001). Mean decreases of between 8 mmHg and 18 mmHg were observed.

Enhancement of energy expenditure following a single oral dose of flavan-3-ols associated with an increase in catecholamine secretion

Numerous clinical studies have reported that ingestion of chocolate reduces the risk of metabolic syndrome. However, the mechanisms by which this occurs remain unclear. In this murine study, the metabolic-enhancing activity of a 10 mg/kg mixture of flavan-3-ol fraction derived from cocoa (FL) was compared with the same single dose of (-)-epicatechin (EC). Resting energy expenditure (REE) was significantly increased in mice treated with the FL versus the group administered the distilled water vehicle (Cont) during periods of ad libitum feeding and fasting. Mice were euthanized under the effect of anesthesia 2, 5, and 20 hr after treatment with FL or Cont while subsequently fasting. The mRNA levels of the uncoupling protein-1 (UCP-1) and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) in brown adipose tissue (BAT) were significantly increased 2 hr after administration of FL. UCP-3 and PGC-1α in the gastrocnemius were significantly increased 2 and 5 hr after administration of the FL. The concentrations of phosphorylated AMP-activated protein kinase (AMPK) 1α were found to be significant in the gastrocnemius of mice 2 and 5 hr after ingesting FL. However, these changes were not observed following treatment with EC. Plasma was collected for measurement of catecholamine levels in other animals euthanized by decapitation 2 and 4 hr after their respective group treatment. Plasma adrenaline level was significantly elevated 2 hr after treatment with FL; however, this change was not observed following the administration of EC alone. The present results indicated that FL significantly enhanced systemic energy expenditure, as evidenced by an accompanying increase in the type of gene expression responsible for thermogenesis and lipolysis, whereas EC exhibited this less robustly or effectively. It was suggested the possible interaction between thermogenic and lipolytic effects and the increase in plasma catecholamine concentrations after administration of a single oral dose of FL.

Realistic intake of a flavanol-rich soluble cocoa product increases HDL-cholesterol without inducing anthropometric changes in healthy and moderately hypercholesterolemic subjects

To assess whether antioxidant, anti-inflammatory and other cardio-protective effects attributed to cocoa are achieved when regularly consuming moderate amounts of a flavanol-rich soluble cocoa product, a non-randomized, controlled, crossover, free-living study was carried out in healthy (n = 24; 25.9 ± 5.6 years) and moderately hypercholesterolemic (200-240 mg dL(-1); n = 20; 30.0 ± 10.3 years) volunteers. Participants consumed two servings per day (7.5 g per serving) of a soluble cocoa product (providing 45.3 mg flavanols per day) in milk, which was compared with consuming only milk during a 4 week period. The effects on systolic and diastolic blood pressure and heart rate were determined, as well as on serum lipid and lipoprotein profiles, interleukins (IL)-1β, IL-6, IL-8, IL-10, tumor necrosis factor-α (TNF-α), monocyte chemoattractant protein-1 (MCP-1), vascular (VCAM-1) and intercellular cell adhesion molecules (ICAM-1), serum malondialdehyde (MDA), carbonyl groups (CG), ferric reducing/antioxidant power (FRAP), oxygen radical absorbance capacity (ORAC), and free radical scavenging capacity (ABTS). During the study, the volunteers' diets and physical activity were also evaluated, as well as any changes in weight, skin folds, circumferences and related anthropometric parameters. Cocoa and certain polyphenol-rich fruits and vegetables and their derivatives were restricted. After consuming the cocoa product positive effects were observed such as an increase in serum HDL-C (p < 0.001) and dietary fiber intake (p = 0.050), whereas IL-10 decreased (p = 0.022). Other cardiovascular-related biomarkers and anthropometric parameters were unaffected. We have therefore concluded that regular consumption of this cocoa product in a Spanish-Mediterranean diet may protect against cardiovascular disease in healthy and hypercholesterolemic subjects without producing any weight gain or other anthropometric changes.

The flavan-3-ol fraction of cocoa powder suppressed changes associated with early-stage metabolic syndrome in high-fat diet-fed rats

AIMS

Previous epidemiological studies have suggested that ingestion of chocolate reduces the risk of cardiovascular disease. In the present study, we examined the effects of flavan-3-ols derived from cocoa on blood pressure, lipolysis, and thermogenesis in rats fed a high-fat diet and that showed early signs of metabolic syndrome.

MAIN METHODS

The rats were divided into three groups, and fed either normal diet (normal), 60% fat high-fat diet (HFD), or HFD containing 0.2% flavan-3-ols (HFD-flavan) for 4 weeks. At the end of the feeding period, blood pressure was measured and animals were sacrificed under anesthesia. Lipolysis and thermogenesis-related protein levels were measured in several tissues by Western blotting, and mitochondrial DNA copy number was measured by RT-PCR.

KEY FINDINGS

Mean blood pressure and epididymal adipose tissue weight of HFD-flavan were significantly lower compared with those of HFD. Uncoupling protein (UCP)1 in brown adipose tissue and UCP3 in gastrocnemius of HFD-flavan were significantly increased compared with those of HFD group. Carnitine palmitoyltransferase (CPT) 2 levels in liver and medium-chain acyl-CoA dehydrogenase (MCAD) levels in gastrocnemius and liver were significantly increased by the supplementation of flavan-3-ols.

SIGNIFICANCE

In addition to having hypotensive effects, flavan-3-ols enhance thermogenesis and lipolysis and consequently reduce white adipose tissue weight gain in response to high-fat diet feeding.

The effects of acute aerobic activity on cognition and cross-domain transfer to eating behavior

Prior studies have demonstrated that a single session of aerobic exercise can enhance cognitive functioning; specifically, the inhibition facet of executive function (EF). Additionally, previous research has demonstrated that inhibitory abilities are essential for effective dietary self-control. However, it is currently unknown whether exercise induced enhancements in EF also facilitate self-control in the dietary domain. The present study sought to determine whether a single session of aerobic exercise enhances EF, and whether there is a transfer effect to dietary self-control. Thirty four undergraduate students were randomly assigned to one of three exercise conditions: (1) minimal exercise; (2) moderate intensity exercise (30% heart rate reserve); (3) vigorous intensity exercise (50% heart rate reserve). After the exercise bout, participants completed three standardized EF tasks followed by a bogus taste test for three appetitive snack foods (milk chocolate and potato chips) and two control foods (dark chocolate and crackers). The amount of food consumed during the taste test was covertly measured. The results revealed a significant main effect of treatment condition on the Stroop task performance, but not Go-NoGo (GNG) and Stop Signal task performance. Findings with respect to food consumption revealed that EF moderated the treatment effect, such that those with larger exercise effects on Stroop performance in the moderate intensity exercise condition consumed more control foods (but not less appetitive foods). These findings support the contention that a single bout of aerobic exercise enhances EF, and may have transfer effects to the dietary domain, but that such effects may be indirect in nature.

Alteration of the systemic and microcirculation by a single oral dose of flavan-3-ols

Several systematic reviews have reported that flow mediated dilatation (FMD) was significantly increased in subjects after ingestion of chocolate that contains flavan-3-ols; however, the mechanisms responsible for this effect are not clear. In this study, we evaluated the effects of a single oral dose of flavan-3-ols on the systemic circulation and microcirculation in the cremaster muscle using intravital video microscopy in vivo. The cremaster muscle in rats was spread over a plastic chamber and a gastric tube was placed into the stomach. Blood flow in the cremasteric artery was determined using a laser Doppler flowmeter, while blood pressure and heart rate were measured by the tail-cuff method. Red blood cell velocity in arterioles and blood flow in the artery were significantly increased 5 min after the administration of 10 mg/kg flavan-3-ols compared with distilled water treatment. The number of capillaries recruited in the cremaster muscle was also significantly increased 15 min after treatment. Microscopic observation confirmed that increased shear stress on endothelial cells was maintained during the measurement period. The mean arterial blood pressure and heart rate were also significantly elevated soon after administration and returned to baseline before the end of the observation period. Plasma nitrate and nitrite levels, and NO phosphorylation of aortic tissue were significantly increased at 60 min after administration of flavan-3-ols. According to these results, a single oral dose of flavan-3-ols elevates blood pressure and flow transiently, and these effects induce NO production through increased shear stress on endothelial cells.

Flavan-3-ol fraction from cocoa powder promotes mitochondrial biogenesis in skeletal muscle in mice

BACKGROUND

Numerous clinical studies have reported that ingestion of chocolate has reduced risk of metabolic syndrome. In order to elucidate the mechanism, we evaluated the influence of flavan-3-ols derived from cocoa powder on energy metabolism in mice using an indirect calorimetric method.

METHOD

The mice were divided into two groups, and administered either distilled water or 50 mg/kg of flavan-3-ol fraction for 2 weeks. At the end of the experimental period, animals were sacrificed after blood pressure and the mean respiratory exchange ratio (RER) over 24 hours were measured.

RESULTS

The mean respiratory exchange ratio (RER) over 24 hours was reduced significantly in the flavan-3-ols group. The mean blood pressure was significantly decreased in flavan-3-ols treatment group compared with control group. The protein level of carnitine palmitoyltransferase 2 (CPT2) was increased significantly by flavan-3-ols in skeletal muscle, but not in liver. Uncoupling protein (UCP) 1 was increased significantly in brown adipose tissue by flavan-3-ols. The mitochondria copy number in gastrocnemius and soleus muscles and brown adipose tissue were increased significantly by administration of flavan-3-ol fraction.

CONCLUSION

These results suggest that flavan-3-ols enhances lipolysis and promotes mitochondrial biogenesis. We conclude that improvement of metabolic syndrome risk factors following ingestion of chocolate may be induced, in part, by the mitochondrial biogenesis-promoting effect of flavan-3-ols.

Oxidised LDL levels decreases after the consumption of ready-to-eat meals supplemented with cocoa extract within a hypocaloric diet

BACKGROUND AND AIMS

Cocoa flavanols are recognised by their favourable antioxidant and vascular effects. This study investigates the influence on health of the daily consumption of ready-to-eat meals supplemented with cocoa extract within a hypocaloric diet, on middle-aged overweight/obese subjects.

METHODS AND RESULTS

Fifty healthy male and female middle-aged volunteers [57.26 ± 5.24 years and body mass index (BMI) 30.59 ± 2.33 kg/m(2)] were recruited to participate in a 4 week randomised, parallel and double-blind study. After following 3 days on a low-polyphenol diet, 25 volunteers received meals supplemented with 1.4 g of cocoa extract (645.3 mg of polyphenols) and the other 25 participants received control meals, within a 15% energy restriction diet. On the 4th week of intervention individuals in both dietary groups improved (p < 0.05) anthropometric, body composition, blood pressure and blood biochemical measurements. Oxidised LDL cholesterol (oxLDL), showed a higher reduction (p = 0.030) in the cocoa group. Moreover, myeloperoxidase (MPO) levels decreased only in the cocoa supplemented group (p = 0.007). Intercellular Adhesion Molecule-1 (sICAM-1) decreased significantly in both groups, while Vascular Cell Adhesion Molecule-1 (sVCAM-1) did not present differences after the 4 weeks of intervention. Interestingly, cocoa intake showed a different effect by gender, presenting more beneficial effects in men.

CONCLUSIONS

The consumption of cocoa extract as part of ready-to-eat meals and within a hypocaloric diet improved oxidative status (oxLDL) in middle-aged subjects, being most remarkable in males.

REGISTRATION NUMBER

Registered at www.clinicaltrials.gov (NCT01596309).

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

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

Nutrition and nutraceutical supplements for the treatment of hypertension: part III

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

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

The consumption of cocoa and dark chocolate is associated with a lower risk of CVD, and improvements in endothelial function may mediate this relationship. Less is known about the effects of cocoa/chocolate on the augmentation index (AI), a measure of vascular stiffness and vascular tone in the peripheral arterioles. We enrolled thirty middle-aged, overweight adults in a randomised, placebo-controlled, 4-week, cross-over study. During the active treatment (cocoa) period, the participants consumed 37 g/d of dark chocolate and a sugar-free cocoa beverage (total cocoa = 22 g/d, total flavanols (TF) = 814 mg/d). Colour-matched controls included a low-flavanol chocolate bar and a cocoa-free beverage with no added sugar (TF = 3 mg/d). Treatments were matched for total fat, saturated fat, carbohydrates and protein. The cocoa treatment significantly increased the basal diameter and peak diameter of the brachial artery by 6% (+2 mm) and basal blood flow volume by 22%. Substantial decreases in the AI, a measure of arterial stiffness, were observed in only women. Flow-mediated dilation and the reactive hyperaemia index remained unchanged. The consumption of cocoa had no effect on fasting blood measures, while the control treatment increased fasting insulin concentration and insulin resistance (P= 0·01). Fasting blood pressure (BP) remained unchanged, although the acute consumption of cocoa increased resting BP by 4 mmHg. In summary, the high-flavanol cocoa and dark chocolate treatment was associated with enhanced vasodilation in both conduit and resistance arteries and was accompanied by significant reductions in arterial stiffness in women.

Regular consumption of a cocoa product improves the cardiometabolic profile in healthy and moderately hypercholesterolaemic adults

Cocoa products present great health potential due to their high content of polyphenols, mainly of flavanols. However, the antioxidant, anti-inflammatory and other health effects of regularly consuming cocoa products seem to depend on the intake and health status of the consumer, etc. and need to be further clarified. A randomised, controlled, cross-over, free-living study was carried out in healthy (n 24) and moderately hypercholesterolaemic (>2000 mg/l, n 20) subjects to assess the influence of regularly consuming (4 weeks) two servings (15 g each) of a cocoa product rich in fibre (containing 33·9 % of total dietary fibre (TDF) and 13·9 mg/g of soluble polyphenols) in milk v. consuming only milk (control) on (1) serum lipid and lipoprotein profile, (2) serum malondialdehyde levels, carbonyl groups, ferric reducing/antioxidant power, oxygen radical absorbance capacity and free radical-scavenging capacity, (3) IL-1β, IL-6, TNF-α, IL-10, IL-8, monocyte chemoattractant protein-1, and vascular and intracellular cell adhesion molecule levels, and (4) systolic and diastolic blood pressure and heart rate. Throughout the study, the diet and physical activity of the volunteers, as well as any possible changes in weight or other anthropometric parameters, were also evaluated. The intake of TDF increased (P< 0·001) to the recommended levels. Serum HDL-cholesterol (HDL-C) levels were increased (P< 0·001), whereas glucose (P= 0·029), IL-1β (P= 0·001) and IL-10 (P= 0·001) levels were decreased. The rest of the studied cardiovascular parameters, as well as the anthropometric ones, remained similar. In conclusion, regularly consuming a cocoa product with milk improves cardiovascular health by increasing HDL-C levels and inducing hypoglycaemic and anti-inflammatory effects in healthy and hypercholesterolaemic individuals without causing weight gain.

Cocoa Consumption Alters the Global DNA Methylation of Peripheral Leukocytes in Humans with Cardiovascular Disease Risk Factors: A Randomized Controlled Trial

DNA methylation regulates gene expression and can be modified by different bioactive compounds in foods, such as polyphenols. Cocoa is a rich source of polyphenols, but its role in DNA methylation is still unknown. The objective was to assess the effect of cocoa consumption on DNA methylation and to determine whether the enzymes involved in the DNA methylation process participate in the mechanisms by which cocoa exerts these effects in humans. The global DNA methylation levels in the peripheral blood were evaluated in 214 volunteers who were pre-hypertensive, stage-1 hypertensive or hypercholesterolemic. The volunteers were divided into two groups: 110 subjects who consumed cocoa (6 g/d) for two weeks and 104 control subjects. In addition, the peripheral blood mononuclear cells (PBMCs) from six subjects were treated with a cocoa extract to analyze the mRNA levels of the DNA methyltransferases (DNMTs), methylenetetrahydrofolate reductase (MTHFR), and methionine synthase reductase (MTRR) genes. Cocoa consumption significantly reduced the DNA methylation levels (2.991±0.366 vs. 3.909±0.380, p<0.001). Additionally, we found an association between the cocoa effects on DNA methylation and three polymorphisms located in the MTHFR, MTRR, and DNMT3B genes. Furthermore, in PBMCs, the cocoa extract significantly lowered the mRNA levels of the DNMTs, MTHFR, and MTRR. Our study demonstrates for the first time that the consumption of cocoa decreases the global DNA methylation of peripheral leukocytes in humans with cardiovascular risk factors. In vitro experiments with PBMCs suggest that cocoa may exert this effect partially via the down-regulation of DNMTs, MTHFR and MTRR, which are key genes involved in this epigenetic process.

TRIAL REGISTRATION

Clinicaltrials.govNCT00511420 and NCT00502047.

Effect of cocoa and theobromine consumption on serum HDL-cholesterol concentrations: a randomized controlled trial

BACKGROUND

Evidence from clinical studies has suggested that cocoa may increase high-density lipoprotein (HDL)-cholesterol concentrations. However, it is unclear whether this effect is attributable to flavonoids or theobromine, both of which are major cocoa components.

OBJECTIVES

We investigated whether pure theobromine increases serum HDL cholesterol and whether there is an interaction effect between theobromine and cocoa.

DESIGN

The study had a 2-center, double-blind, randomized, placebo-controlled, full factorial parallel design. After a 2-wk run-in period, 152 healthy men and women (aged 40-70 y) were randomly allocated to consume one 200-mL drink/d for 4 wk that contained 1) cocoa, which naturally provided 150 mg theobromine and 325 mg flavonoids [cocoa intervention (CC)], 2) 850 mg pure theobromine [theobromine intervention (TB)], 3) cocoa and added theobromine, which provided 1000 mg theobromine and 325 mg flavonoids [theobromine and cocoa intervention (TB+CC)], or 4) neither cocoa nor theobromine (placebo). Blood lipids and apolipoproteins were measured at the start and end of interventions.

RESULTS

In a 2-factor analysis, there was a significant main effect of the TB (P < 0.0001) but not CC (P = 0.1288) on HDL cholesterol but no significant interaction (P = 0.3735). The TB increased HDL-cholesterol concentrations by 0.16 mmol/L (P < 0.0001). Furthermore, there was a significant main effect of the TB on increasing apolipoprotein A-I (P < 0.0001) and decreasing apolipoprotein B and LDL-cholesterol concentrations (P < 0.02).

CONCLUSIONS

Theobromine independently increased serum HDL-cholesterol concentrations by 0.16 mmol/L. The lack of significant cocoa and interaction effects suggested that theobromine may be the main ingredient responsible for the HDL cholesterol-raising effect. This trial was registered at clinicaltrials.gov as NCT01481389.

Cocoa and human health

Cocoa is a dry, powdered, nonfat component product prepared from the seeds of the Theobroma cacao L. tree and is a common ingredient of many food products, particularly chocolate. Nutritionally, cocoa contains biologically active substances that may affect human health: flavonoids (epicatechin and oligomeric procyanidins), theobromine, and magnesium. Theobromine and epicatechin are absorbed efficiently in the small intestine, and the nature of their conjugates and metabolites are now known. Oligomeric procyanidins are poorly absorbed in the small intestine, but catabolites are very efficiently absorbed after microbial biotransformation in the colon. A significant number of studies, using in vitro and in vivo approaches, on the effects of cocoa and its constituent flavonoids have been conducted. Most human intervention studies have been performed on cocoa as an ingredient, whereas many in vitro studies have been performed on individual components. Approximately 70 human intervention studies have been carried out on cocoa and cocoa-containing products over the past 12 years, with a variety of endpoints. These studies indicate that the most robust biomarkers affected are endothelial function, blood pressure, and cholesterol level. Mechanistically, supporting evidence shows that epicatechin affects nitric oxide synthesis and breakdown (via inhibition of nicotinamide adenine di-nucleotide phosphate oxidase) and the substrate arginine (via inhibition of arginase), among other targets. Evidence further supports cocoa as a biologically active ingredient with potential benefits on biomarkers related to cardiovascular disease. However, the calorie and sugar content of chocolate and its contribution to the total diet should be taken into account in intervention studies.

Flavan 3-ols improve metabolic syndrome risk factors: evidence and mechanisms

Flavan 3-ols, a type of polyphenolic substance, are distributed in a number of plant foods. Of these foods, chocolate is very rich in flavan 3-ols as flavan 3-ol monomers, (+)-catechin and (−)-epicatechin, and the oligomers as procyanidins. There is evidence that cacao products containing flavan 3-ols have the potential to contribute to the risk reduction of cardiometabolic disorders according to recent epidemiological or intervention studies. This review focuses on recent advances in research on the ability of flavan 3-ols to reduce the risk of cardiovascular disease as a result of improving metabolic syndrome risk factors and these mechanisms.

Behavioural effects of compounds co-consumed in dietary forms of caffeinated plants

Research into the cognitive and mood effects of caffeine in human subjects has highlighted some fairly robust and well-accepted effects. However, the majority of these studies have focused on caffeine in isolation; whilst caffeine is normally consumed in the form of plant-derived products and extracts that invariably contain other potentially bioactive phytochemicals. The aim of the present review is to consider the possible mechanisms of action of co-occurring phytochemicals, and any epidemiological evidence suggesting that they contribute to potential health benefits ascribed to caffeine. Intervention studies to date that have been conducted to explore the effects on brain function of the non-caffeine components in caffeine-bearing plants (coffee, tea, cocoa, guaraná), either alone or in combination with caffeine, will also be summarised. Research is beginning to accumulate showing independent effects for several of the phytochemicals that co-occur with caffeine, and/or a modulation of the effects of caffeine when it is co-consumed with these naturally concomitant phytochemicals. The present review highlights that more research aimed at understanding the effects of these compounds is needed and, more importantly, the synergistic relationship that they may have with caffeine.

Bone marrow stromal and vascular smooth muscle cells have chemosensory capacity via bitter taste receptor expression

The ability of cells to detect changes in the microenvironment is important in cell signaling and responsiveness to environmental fluctuations. Our interest is in understanding how human bone marrow stromal-derived cells (MSC) and their relatives, vascular smooth muscle cells (VSMC), interact with their environment through novel receptors. We found, through a proteomics screen, that MSC express the bitter taste receptor, TAS2R46, a protein more typically localized to the taste bud. Expression was also confirmed in VSMCs. A prototypical bitter compound that binds to the bitter taste receptor class, denatonium, increased intracellular calcium release and decreased cAMP levels as well as increased the extracellular release of ATP in human MSC. Denatonium also bound and activated rodent VSMC with a change in morphology upon compound exposure. Finally, rodents given denatonium in vivo had a significant drop in blood pressure indicating a vasodilator response. This is the first description of chemosensory detection by MSC and VSMCs via a taste receptor. These data open a new avenue of research into discovering novel compounds that operate through taste receptors expressed by cells in the marrow and vascular microenvironments.

Characterisation of hypertensive patients with improved endothelial function after dark chocolate consumption

Recent findings indicate an inverse relationship between cardiovascular disease and consumption of flavonoids. We aimed to identify clinical and vascular parameters of treated hypertensive who present beneficial effects of dark chocolate for one-week period on vascular function. Twenty-one hypertensive subjects, aged 40–65 years, were included in a prospective study with measurement of blood pressure (BP), brachial flow-mediated dilatation (FMD), peripheral arterial tonometry, and central hemodynamic parameters. These tests were repeated after seven days of eating dark chocolate 75 g/day. Patients were divided according to the response in FMD: responders (n = 12) and nonresponders (n = 9). The responder group presented lower age (54 ± 7 versus 61 ± 6 years, P = 0.037), Framingham risk score (FRS) (2.5 ± 1.8 versus 8.1 ± 5.1%, P = 0.017), values of peripheral (55 ± 9 versus 63 ± 5 mmHg, P = 0.041), and central pulse pressure (PP) (44 ± 10 versus 54 ± 6 mmHg, P = 0.021). FMD response showed negative correlation with FRS (r = −0.60, P = 0.014), baseline FMD (r = −0.54, P = 0.011), baseline reactive hyperemia index (RHI; r = −0.56, P = 0.008), and central PP (r = −0.43, P = 0.05). However, after linear regression analysis, only FRS and baseline RHI were associated with FMD response. In conclusion, one-week dark chocolate intake significantly improved endothelial function and reduced BP in younger hypertensive with impaired endothelial function in spite of lower cardiovascular risk.

Cocoa Polyphenols: Can We Consider Cocoa and Chocolate as Potential Functional Food?

Chocolate has been consumed as confection, aphrodisiac, and folk medicine for many years before science proved its potential health benefiting effects. Main compounds of cocoa and chocolate which contribute to human health are polyphenols that act as antioxidants and have potential anti-inflammatory, cardioprotective, antihepatotoxic, antibacterial, antiviral, antiallergenic, and anticarcinogenic properties. This paper gives a short overview of scientific literature regarding cocoa polyphenols and influence of cocoa and chocolate on human health. Although research on health benefits of dark chocolate and cocoa is quite extensive nowadays and shows potentially beneficial effects of dark chocolate and cocoa, there are still lots of unknowns and some controversies. This is obviously an area that needs more research in order to determine factual influence of chocolate on health.

Blood pressure-lowering effect of dietary (-)-epicatechin administration in L-NAME-treated rats is associated with restored nitric oxide levels

Epidemiological and intervention studies have shown that the intake of certain chocolates or cocoa products decreases blood pressure (BP) in humans. (-)-Epicatechin is the most abundant flavanol present in cocoa seeds and its derived foods. This work investigates the effects of dietary (-)-epicatechin on BP in rats that received N(ω)-nitro-l-arginine methyl ester (L-NAME) for 4 days. (-)-Epicatechin administration prevented the 42mm Hg increase in BP associated with the inhibition of NO production in a dose-dependent manner (0.2-4.0g/kg diet). This BP effect was associated with a reduction in L-NAME-mediated increase in the indexes of oxidative stress (plasma TBARS and GSSG/GSH(2) ratio) and with a restoration of the NO concentration. At the vascular level, none of the treatments modified NOS expression, but (-)-epicatechin administration avoided the L-NAME-mediated decrease in eNOS activity and increase in both superoxide anion production and NOX subunit p47(phox) expression. In summary, (-)-epicatechin was able to prevent the increase in BP and in oxidative stress and restored NO bioavailability. The fact that (-)-epicatechin is present in several plants usually consumed by humans gives the possibility of developing diets rich in those plants or pharmacological strategies using that flavonoid to diminish BP in hypertensive subjects.

Consumption of high-polyphenol dark chocolate improves endothelial function in individuals with stage 1 hypertension and excess body weight

Background. Hypertension and excess body weight are important risk factors for endothelial dysfunction. Recent evidence suggests that high-polyphenol dark chocolate improves endothelial function and lowers blood pressure. This study aimed to evaluate the association of chocolate 70% cocoa intake with metabolic profile, oxidative stress, inflammation, blood pressure, and endothelial function in stage 1 hypertensives with excess body weight. Methods. Intervention clinical trial includes 22 stage 1 hypertensives without previous antihypertensive treatment, aged 18 to 60 years and presents a body mass index between 25.0 and 34.9 kg/m(2). All participants were instructed to consume 50 g of chocolate 70% cocoa/day (2135 mg polyphenols) for 4 weeks. Endothelial function was evaluated by peripheral artery tonometry using Endo-PAT 2000 (Itamar Medical). Results. Twenty participants (10 men) completed the study. Comparison of pre-post intervention revealed that (1) there were no significant changes in anthropometric parameters, percentage body fat, glucose metabolism, lipid profile, biomarkers of inflammation, adhesion molecules, oxidized LDL, and blood pressure; (2) the assessment of endothelial function through the reactive hyperemia index showed a significant increase: 1.94 ± 0.18 to 2.22 ± 0.08, P = 0.01. Conclusion.In individuals with stage 1 hypertension and excess body weight, high-polyphenol dark chocolate improves endothelial function.

Blueberry supplementation induces spatial memory improvements and region-specific regulation of hippocampal BDNF mRNA expression in young rats

RATIONALE

Flavonoid-rich foods have been shown to be able to reverse age-related cognitive deficits in memory and learning in both animals and humans. However, to date, there have been only a limited number of studies investigating the effects of flavonoid-rich foods on cognition in young/healthy animals.

OBJECTIVES

The aim of this study was to investigate the effects of a blueberry-rich diet in young animals using a spatial working memory paradigm, the delayed non-match task, using an eight-arm radial maze. Furthermore, the mechanisms underlying such behavioural effects were investigated.

RESULTS

We show that a 7-week supplementation with a blueberry diet (2 % w/w) improves the spatial memory performance of young rats (2 months old). Blueberry-fed animals also exhibited a faster rate of learning compared to those on the control diet. These behavioural outputs were accompanied by the activation of extracellular signal-related kinase (ERK1/2), increases in total cAMP-response element-binding protein (CREB) and elevated levels of pro- and mature brain-derived neurotrophic factor (BDNF) in the hippocampus. Changes in hippocampal CREB correlated well with memory performance. Further regional analysis of BDNF gene expression in the hippocampus revealed a specific increase in BDNF mRNA in the dentate gyrus and CA1 areas of hippocampi of blueberry-fed animals.

CONCLUSIONS

The present study suggests that consumption of flavonoid-rich blueberries has a positive impact on spatial learning performance in young healthy animals, and these improvements are linked to the activation of ERK-CREB-BDNF pathway in the hippocampus.

Effect of cocoa on blood pressure

BACKGROUND

High blood pressure is an important risk factor for cardiovascular disease attributing to about 50% of cardiovascular events worldwide and 37% of cardiovascular related deaths in Western populations. Epidemiological studies suggest that cocoa rich products reduce the risk of cardiovascular disease. Flavanols found in cocoa have been shown to increase the formation of endothelial nitric oxide which promotes vasodilation and therefore blood pressure reduction. Previous meta-analyses have shown that cocoa-rich foods may reduce blood pressure. Recently additional trials had conflicting results.

OBJECTIVES

To determine the effect of flavanol-rich chocolate or cocoa products on blood pressure in people with or without hypertension.

SEARCH METHODS

We searched the following electronic databases from inception to November 2011: Cochrane Hypertension Group Specialised Register, CENTRAL, MEDLINE and EMBASE. In addition we searched international trial registries, and the reference lists of review articles and included trials.

SELECTION CRITERIA

Randomised controlled trials (RCT) investigating the effects of chocolate or cocoa products on systolic and diastolic blood pressure in adults for a minimum of two weeks duration.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed the risk of bias in each trial in consultation with a third author. Random effects meta-analyses on all studies fitting the inclusion criteria were conducted using Review Manager version 5.1 and Stata version 12. Heterogeneity was explored by subgroup analyses and univariate meta-regression analysis of several variables including dosage of flavanol content (total or monomers) in chocolate or cocoa products, blinding, baseline blood pressure, theobromine content, sugar content, body-mass-index (BMI), duration and age.

MAIN RESULTS

Twenty studies met the inclusion criteria. Meta-analyses of the 20 studies involving 856 mainly healthy participants revealed a statistically significant blood pressure reducing effect of flavanol-rich cocoa products compared with control in short-term trials of 2-18 weeks duration: Mean difference SBP (95%CI): -2.77 (-4.72, -0.82) mm Hg, p=0.005, n=20; mean difference DBP (95%CI): - 2.20 (-3.46, -0.93) mm Hg, p=0.006, n=19 available for DBP.Trials provided participants with 30-1080 mg of flavanols (mean=545.5 mg) in 3.6-105 g of cocoa products per day in the active intervention group. In half of the trials (n=10) the active group consumed 500-750 mg of flavanols per day. The control group received either a flavanol-free product (n=12) or a low-flavanol containing cocoa powder (6.4 and 41 mg flavanols, n=8). Subgroup meta-analysis of trials with a flavanol-free control group revealed a significant blood pressure reducing effect, in contrast to trials using a low-flavanol product in the control group. This analysis may have been confounded by trial duration and the level of blinding of participants.Trial duration was short (mean 4.4 weeks, range 2-8 weeks, n=19, and one trial of 18 weeks). A significant blood pressure reducing effect was evident in trials of 2 weeks duration (n=9), but not in trials of >2 weeks duration (n=11). It is important to note that seven out of the nine trials (78%) of 2 weeks duration also had a flavanol-free control group. Therefore, subgroup analysis by duration might be confounded by flavanol dosage used in the control groups, and the level of blinding of participants.Adverse effects including gastrointestinal complaints and distaste of the trial product were reported by 5% of patients in the active cocoa intervention group and 1% of patients in the control groups.

AUTHORS' CONCLUSIONS

Flavanol-rich chocolate and cocoa products may have a small but statistically significant effect in lowering blood pressure by 2-3 mm Hg in the short term.Our findings are limited by the heterogeneity between trials, which was explored by univariate meta-regression and subgroup analyses. Subgroup meta-analysis of trials using a flavanol-free control group revealed a significant blood pressure reducing effect of cocoa, whereas analysis of trials using a low-flavanol control product did not. While it appears that shorter trials of 2 weeks duration were more effective, analysis may be confounded by type of control and unblinding of participants, as the majority of 2-week trials also used a flavanol-free control and unblinding of participants. Results of these and other subgroup analyses based on, for example, age of participants, should be interpreted with caution and need to be confirmed or refuted in trials using direct randomized comparison.Long-term trials investigating the effect of cocoa products are needed to determine whether or not blood pressure is reduced on a chronic basis by daily ingestion of cocoa. Furthermore, long-term trials investigating the effect of cocoa on clinical outcomes are also needed to assess whether cocoa has an effect on cardiovascular events and to assess potential adverse effects associated with chronic ingestion of cocoa products.

Epicatechin ingested via cocoa products reduces blood pressure in humans: a nonlinear regression model with a Bayesian approach

BACKGROUND

Four meta-analyses of randomized controlled trials (RCTs) based on the classical random-effects model showed that cocoa consumption can reduce systolic blood pressure (SBP) and diastolic blood pressure (DBP). Because epicatechin is suggested to be responsible for the treatment effect, changes in blood pressure should depend on the dose of ingested epicatechin, which may explain the between-study differences.

OBJECTIVE

The objective was to quantify the effect of epicatechin ingested via cocoa products on changes in SBP and DBP.

DESIGN

A nonlinear meta-regression model was chosen to investigate the impact of the epicatechin dose on changes in SBP and DBP. A Bayesian approach using Markov chain Monte Carlo methods was applied for an appropriate treatment of the nonlinearity.

RESULTS

Data from 16 RCTs on SBP and 15 RCTs on DBP were included. The dose of epicatechin ingested via cocoa products influenced the changes in SBP and DBP. The asymptotic limit for the reduction was estimated at -4.6 mm Hg (95% CI: -5.4, -3.9 mm Hg) for SBP and at -2.1 mm Hg (95% CI: -2.7, -1.6 mm Hg) for DBP. An intake of 25 mg epicatechin/d led to a mean reduction of -4.1 mm Hg (95% CI: -4.6, -3.6 mm Hg) in SBP and of -2.0 mm Hg (95% CI: -2.4, -1.5 mm Hg) in DBP.

CONCLUSIONS

Blood pressure reduction by consumption of cocoa products depends on the dose of ingested epicatechin, which explains most of the between-study differences in classical meta-analyses. Similar effects may be achieved by consumption of other foods that are also rich in epicatechin.

The effectiveness and cost effectiveness of dark chocolate consumption as prevention therapy in people at high risk of cardiovascular disease: best case scenario analysis using a Markov model

OBJECTIVE

To model the long term effectiveness and cost effectiveness of daily dark chocolate consumption in a population with metabolic syndrome at high risk of cardiovascular disease.

DESIGN

Best case scenario analysis using a Markov model.

SETTING

Australian Diabetes, Obesity and Lifestyle study.

PARTICIPANTS

2013 people with hypertension who met the criteria for metabolic syndrome, with no history of cardiovascular disease and not receiving antihypertensive therapy.

MAIN OUTCOME MEASURES

Treatment effects associated with dark chocolate consumption derived from published meta-analyses were used to determine the absolute number of cardiovascular events with and without treatment. Costs associated with cardiovascular events and treatments were applied to determine the potential amount of funding required for dark chocolate therapy to be considered cost effective.

RESULTS

Daily consumption of dark chocolate (polyphenol content equivalent to 100 g of dark chocolate) can reduce cardiovascular events by 85 (95% confidence interval 60 to 105) per 10,000 population treated over 10 years. $A40 (£25; €31; $42) could be cost effectively spent per person per year on prevention strategies using dark chocolate. These results assume 100% compliance and represent a best case scenario.

CONCLUSIONS

The blood pressure and cholesterol lowering effects of dark chocolate consumption are beneficial in the prevention of cardiovascular events in a population with metabolic syndrome. Daily dark chocolate consumption could be an effective cardiovascular preventive strategy in this population.

Influence of sugar type on the bioavailability of cocoa flavanols

The beneficial effects of cocoa on vascular function are mediated by the absorption of monomeric flavanols into the circulation from the small intestine. As such, an understanding of the impact of the food matrix on the delivery of flavanols to the circulation is critical in assessing the potential vascular impact of a food. In the present study, we investigated the impact of carbohydrate type on flavanol absorption and metabolism from chocolate. A randomised, double-blind, three-arm cross-over study was conducted, where fifteen volunteers were randomly assigned to either a high-flavanol (266 mg) chocolate containing maltitol, a high-flavanol (251 mg) chocolate with sucrose or a low-flavanol (48 mg) chocolate with sucrose. Test chocolates were matched for micro- and macronutrients, including the alkaloids theobromine and caffeine, and were similar in taste and appearance. Total flavanol absorption was lower after consumption of the maltitol-containing test chocolate compared with following consumption of its sucrose-containing equivalent (P = 0·002). Although the O-methylation pattern observed for absorbed flavanols was unaffected by sugar type, individual levels of unmethylated ( - )-epicatechin metabolites, 3'-O-methyl-epicatechin and 4'-O-methyl-epicatechin metabolites were lower for the maltitol-containing test chocolate compared with the sucrose-containing equivalent. Despite a reduction in the total plasma pool of flavanols, the maximum time (T max) was unaffected. The present data indicate that full assessment of intervention treatments is vital in future intervention trials with flavanols and that carbohydrate content is an important determinant for the optimal delivery of flavanols to the circulation.

Effects of chocolate, cocoa, and flavan-3-ols on cardiovascular health: a systematic review and meta-analysis of randomized trials

BACKGROUND

There is substantial interest in chocolate and flavan-3-ols for the prevention of cardiovascular disease (CVD).

OBJECTIVE

The objective was to systematically review the effects of chocolate, cocoa, and flavan-3-ols on major CVD risk factors.

DESIGN

We searched Medline, EMBASE, and Cochrane databases for randomized controlled trials (RCTs) of chocolate, cocoa, or flavan-3-ols. We contacted authors for additional data and conducted duplicate assessment of study inclusion, data extraction, validity, and random-effects meta-analyses.

RESULTS

We included 42 acute or short-term chronic (≤18 wk) RCTs that comprised 1297 participants. Insulin resistance (HOMA-IR: -0.67; 95% CI: -0.98, -0.36) was improved by chocolate or cocoa due to significant reductions in serum insulin. Flow-mediated dilatation (FMD) improved after chronic (1.34%; 95% CI: 1.00%, 1.68%) and acute (3.19%; 95% CI: 2.04%, 4.33%) intakes. Effects on HOMA-IR and FMD remained stable to sensitivity analyses. We observed reductions in diastolic blood pressure (BP; -1.60 mm Hg; 95% CI: -2.77, -0.43 mm Hg) and mean arterial pressure (-1.64 mm Hg; 95% CI: -3.27, -0.01 mm Hg) and marginally significant effects on LDL (-0.07 mmol/L; 95% CI: -0.13, 0.00 mmol/L) and HDL (0.03 mmol/L; 95% CI: 0.00, 0.06 mmol/L) cholesterol. Chocolate or cocoa improved FMD regardless of the dose consumed, whereas doses >50 mg epicatechin/d resulted in greater effects on systolic and diastolic BP. GRADE (Grading of Recommendations, Assessment, Development and Evaluation, a tool to assess quality of evidence and strength of recommendations) suggested low- to moderate-quality evidence of beneficial effects, with no suggestion of negative effects. The strength of evidence was lowered due to unclear reporting for allocation concealment, dropouts, missing data on outcomes, and heterogeneity in biomarker results in some studies.

CONCLUSIONS

We found consistent acute and chronic benefits of chocolate or cocoa on FMD and previously unreported promising effects on insulin and HOMA-IR. Larger, longer-duration, and independently funded trials are required to confirm the potential cardiovascular benefits of cocoa flavan-3-ols.

Cocoa, hazelnuts, sterols and soluble fiber cream reduces lipids and inflammation biomarkers in hypertensive patients: a randomized controlled trial

Background

Cocoa, mixed with other food ingredients, intake can have beneficial effects on cardiovascular disease (CVD) biomarkers. We compared the effects of 4 cocoa cream products on some of these biomarkers.

Methods and Findings

In this multi-centered, randomized, controlled, double-blind, parallel trial, volunteers (n = 113; age range: 43–65 years) who were pre-hypertensive, stage-1 hypertensive and hypercholesterolemic received one of 4 cocoa cream products (13 g/unit; 1 g cocoa/unit, 6 units/d; 465 Kcal/d) added to a low saturated fat diet for 4 weeks. The groups were: A) (n = 28), cocoa cream considered as control; B) (n = 28), cocoa+hazelnut cream (30 g/d hazelnuts); C) (n = 30), cocoa+hazelnuts+phytosterols (2 g/d); and D) (n = 27), cocoa+hazelnuts+phytosterols+soluble fiber (20 g/d) the patented “LMN product”. Primary outcome measures were BP, LDL-c, apolipoprotein B-100 (Apo B), ApoB/ApoA ratio, oxidized LDL (oxLDL) and high-sensitive C-reactive protein (hsCRP) determined at baseline and post-cocoa cream product intake. Statistical analysis used was ANCOVA or mixed models (in case of repeated measurements), with baseline observation included as a covariate. After 4 weeks, compared to product A, product C reduced LDL-c by 11.2%, Apo B by 8.1% and ApoB/ApoA ratio by 7.8% (P = 0.01). LMN decreased LDL-c by 9.2%, Apo B-100 by 8.5%, ApoB/ApoA ratio by 10.5%, hsCRP by 33.4% and oxLDL by 5.9% (P = 0.01). Surprisingly, even “control” product A reduced systolic BP (−7.89 mmHg; 95%CI: −11.45 to −4.3) and diastolic BP (−5.54 mmHg; 95%CI: −7.79 to −3.29). The BP reductions were similar with the other 3 products. Limitations of the study are that the trial period was relatively short and that a better “BP control” product would have been preferable.

Conclusion

The creams (particularly the LMN) have anti-inflammatory and antioxidant effects in addition to lowering LDL-c, Apo B and ApoB/ApoA ratio. Thus, the soluble fiber effects amplified with sterols (as contained in the cocoa creams) provide new dietary therapeutic perspectives.

Trial Registration

Clinicaltrials.gov NCT00511420

Cocoa intake and arterial stiffness in subjects with cardiovascular risk factors

BACKGROUND

To analyze the relationship of cocoa intake to central and peripheral blood pressure, arterial stiffness, and carotid intima-media thickness in subjects with some cardiovascular risk factor.

FINDINGS

DESIGN

A cross-sectional study of 351 subjects (mean age 54.76 years, 62.4% males).

MEASUREMENTS

Intake of cocoa and other foods using a food frequency questionnaire, central and peripheral (ambulatory and office) blood pressure, central and peripheral augmentation index, pulse wave velocity, ambulatory arterial stiffness index, carotid intima-media thickness, and ankle-brachial index.

RESULTS

Higher pulse wave velocity and greater cardiovascular risk were found in non-cocoa consumers as compared to high consumers (p < 0.05). In a multivariate analysis, these differences disappeared after adjusting for age, gender, the presence of diabetes, systolic blood pressure and antihypertensive and lipid-lowering drug use. All other arterial stiffness measures (central and peripheral augmentation index, ambulatory arterial stiffness index, ankle-brachial index, and carotid intima-media thickness) showed no differences between the different consumption groups.

CONCLUSIONS

In subjects with some cardiovascular risk factors, cocoa consumption does not imply improvement in the arterial stiffness values.

TRIAL REGISTRATION

Clinical Trials.gov Identifier: NCT01325064.