Flavanol-rich chocolate acutely improves arterial function and working memory performance counteracting the effects of sleep deprivation in healthy individuals

Potential preservative mechanisms of cardiac rehabilitation pathways on endothelial function in coronary heart disease

Cardiac rehabilitation, a comprehensive exercise-based lifestyle and medical management, is effective in decreasing morbidity and improving life quality in patients with coronary heart disease. Endothelial function, an irreplaceable indicator in coronary heart disease progression, is measured by various methods in traditional cardiac rehabilitation pathways, including medicinal treatment, aerobic training, and smoking cessation. Nevertheless, studies on the effect of some emerging cardiac rehabilitation programs on endothelial function are limited. This article briefly reviewed the endothelium-beneficial effects of different cardiac rehabilitation pathways, including exercise training, lifestyle modification and psychological intervention in patients with coronary heart disease, and related experimental models, and summarized both uncovered and potential cellular and molecular mechanisms of the beneficial roles of various cardiac rehabilitation pathways on endothelial function. In exercise training and some lifestyle interventions, the enhanced bioavailability of nitric oxide, increased circulating endothelial progenitor cells (EPCs), and decreased oxidative stress are major contributors to preventing endothelial dysfunction in coronary heart disease. Moreover, the preservation of endothelial-dependent hyperpolarizing factors and inflammatory suppression play roles. On the one hand, to develop more endothelium-protective rehabilitation methods in coronary heart disease, adequately designed and sized randomized multicenter clinical trials should be advanced using standardized cardiac rehabilitation programs and existing assessment methods. On the other hand, additional studies using suitable experimental models are warranted to elucidate the relationship between some new interventions and endothelial protection in both macro- and microvasculature.

Concurrent consumption of cocoa flavanols and caffeine does not acutely modulate working memory and attention

PURPOSE

Consumption of cocoa flavanols and caffeine might acutely enhance cognition, particularly in synergy. Due to the use of multifaceted tasks in prior research, it is unclear precisely which cognitive functions are implicated. Here we aimed to assess the acute effects of the (joint) ingestion of cocoa flavanols and caffeine on temporal attention, spatial attention, and working memory.

METHODS

In four separate sessions of a randomized, double-blind, placebo-controlled, crossover trial, 48 young adult participants consumed a placebo drink, a cocoa flavanols (415 mg) drink, a caffeine (215 mg) drink, and a drink containing both concurrently. In each session, after ingestion, we tested performance in three cognitive tasks. We tested temporal attention in a dual-target rapid serial visual presentation paradigm, known to elicit the attentional blink, in which the time between the targets was manipulated. We measured spatial attention in a visual search task, where we varied the number of distractors that appeared simultaneously with the target. We tested working memory in a delayed recall task, in which the number of stimuli to be remembered was manipulated.

RESULTS

We obtained the expected performance pattern in each task, but found no evidence for modulation of response accuracy or reaction times by the ingestion of either substance, nor of their combined ingestion, even in the most challenging task conditions.

CONCLUSIONS

We conclude that, even when jointly ingested, neither the tested amount of cocoa flavanols nor caffeine have acute effects that are robustly measurable on cognitive tasks that target attention and working memory specifically.

The effects of dark chocolate on cognitive performance during cognitively demanding tasks: A randomized, single-blinded, crossover, dose-comparison study

Dark chocolate, rich in polyphenols, increases cerebral blood flow and improves cognitive function. This study aimed to determine whether the consumption of chocolate with a high concentration of polyphenols helps to maintain cognitive performance during cognitively demanding tasks. In this randomized, single-blinded, crossover, dose-comparison study, 18 middle-aged adults consumed two types of chocolate (25 g each), one with a high concentration (635.0 mg) and the other with a low concentration (211.7 mg) of cacao polyphenols, and performed a cognitive task requiring response inhibition and selective attention over two time periods (15-30 min and 40-55 min after consumption, respectively). Autonomic nerve function and subjective feelings, such as fatigue and concentration, were measured before food intake and after the second task to assess the participant's state. The results showed that the average reaction time between the first and second sessions was not significantly different for either high- or low-concentration chocolate consumption. However, the percentage of correct responses was similar in the first (96.7 %) and second (96.8 %) sessions for high-concentration chocolate consumption and significantly lower for low-concentration chocolate consumption in the second (96.4 %) session than in the first session (97.3 %). Autonomic nerve function showed a significant increase in sympathetic nerve activity after the second task with high-concentration chocolate consumption, while subjective feelings showed an increase in mental fatigue for both chocolate types but a significant decrease in concentration only after the second task with low-concentration chocolate consumption. These findings suggest that dark chocolate consumption contributes to the maintenance of performance and concentration in continuous and demanding cognitive tasks.

Dietary polyphenols and sleep modulation: Current evidence and perspectives

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

The Acute and Chronic Effects of Lion's Mane Mushroom Supplementation on Cognitive Function, Stress and Mood in Young Adults: A Double-Blind, Parallel Groups, Pilot Study

BACKGROUND

Given the bioactive properties and limited work to date, Hericium erinaceus (Lion's mane) shows promise in improving cognitive function and mood. However, much of the human research has concentrated on chronic supplementation in cognitively compromised cohorts.

OBJECTIVE

The current pilot study investigated the acute and chronic (28-day) cognitive and mood-enhancing effects of Hericium erinaceus in a healthy, young adult cohort.

DESIGN

This randomized, double-blind, placebo-controlled, parallel-groups design investigated the acute (60 min post dose) and chronic (28-day intervention) effects of 1.8 g Hericium erinaceus in 41 healthy adults aged 18-45 years.

RESULTS

Analysis revealed that following a single dose of Hericium erinaceus, participants performed quicker on the Stroop task (p = 0.005) at 60 min post dose. A trend towards reduced subjective stress was observed following 28-day supplementation (p = 0.051).

CONCLUSIONS

The findings tentatively suggest that Hericium erinaceus may improve speed of performance and reduce subjective stress in healthy, young adults. However, null and limited negative findings were also observed. Given the small sample size, these findings should be interpreted with caution. Further investigation in larger sample sizes is crucial, however the findings of this trial offer a promising avenue of interest.

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

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

Post-Prandial Cognitive and Blood Pressure Effects of a DHA-Rich Omega-3 Powder in Middle-Aged Males: A Pilot Study

The use of omega-3 polyunsaturated fatty acid (ω-3 PUFA) supplements is increasingly common among middle-aged and older adults. Users of ω-3 PUFA supplements often report using such supplements to support cognitive health, despite mixed findings reported within the ω-3 PUFA literature. To date, very few studies have explored cognitive effects in distinctly middle-aged (40 to 60 years) adults, and none have examined the acute effects (in the hours following a single dose) on cognitive performance. The current study evaluated whether a single dose of ω-3 PUFA (4020 mg docosahexaenoic acid and 720 mg eicosapentaenoic acid) influences cognitive performance and cardiovascular function in middle-aged males. Cognitive performance and cardiovascular function were assessed before and 3.5-4 h after consumption of a high dose of ω-3 PUFA (DHA + EPA) or placebo, incorporated into a standardized meal (i.e., single serve of Greek yogurt). In this study of middle-aged males, no significant differential treatment effects were observed for cognitive performance. However, a significant reduction in aortic systolic blood pressure (pre-dose to post-dose) was apparent following consumption of the ω-3 PUFA (DHA + EPA) treatment (mean difference = -4.11 mmHg, p = 0.004) but not placebo (mean difference = -1.39 mmHg, p = 0.122). Future replication in a sample comprising females, as well as patients with hypertension, is merited.

Dark Chocolate Intake May Reduce Fatigue and Mediate Cognitive Function and Gray Matter Volume in Healthy Middle-Aged Adults

Background

Dark chocolate has attracted attention for its potential for cognitive improvement. Though some reports indicate that dark chocolate is good for cognitive function, others raise doubts. This inconsistency in past results reflecting the relationship between dark chocolate and cognitive function indicates the potential existence of factors that mediate between dark chocolate intake and cognitive function.

Methods

With the hypothesis that fatigue may be one such mediating factor, we performed a four-week randomized control study to seek a link between dark chocolate consumption, cognitive function, fatigue, and the brain in middle-aged adults.

Results

We found that dark chocolate reduced mental and physical fatigue, and a path analysis revealed that it enhanced vitality, executive function, memory, and gray matter volume both directly and indirectly. Fatigue reduction was also associated with an improvement in physical function, which had a positive impact on emotional functioning, relief of bodily pain, and social functioning.

Conclusions

Our results suggest that dark chocolate may help reduce fatigue in individuals, leading to improvements in brain health and various cognitive functions as well as in quality of life.

Cocoa Extract Provides Protection against 6-OHDA Toxicity in SH-SY5Y Dopaminergic Neurons by Targeting PERK

Parkinson’s disease (PD) represents one of the most common neurodegenerative disorders, characterized by a dopamine (DA) deficiency in striatal synapses and misfolded toxic α-synuclein aggregates with concomitant cytotoxicity. In this regard, the misfolded proteins accumulation in neurodegenerative disorders induces a remarkable perturbations of endoplasmic reticulum (ER) homeostasis leading to persistent ER stress, which in turn, effects protein synthesis, modification, and folding quality control. A large body of evidence suggests that natural products target the ER stress signaling pathway, exerting a potential action in cancers, diabetes, cardiovascular and neurodegenerative diseases. This study aims to assess the neuroprotective effect of cocoa extract and its purified fractions against a cellular model of Parkinson’s disease represented by 6-hydroxydopamine (6-OHDA)-induced SH-SY5Y human neuroblastoma. Our findings demonstrate, for the first time, the ability of cocoa to specifically targets PERK sensor, with significant antioxidant and antiapoptotic activities as both crude and fractioning extracts. In addition, cocoa also showed antiapoptotic properties in 3D cell model and a notable ability to inhibit the accumulation of α-synuclein in 6-OHDA-induced cells. Overall, these results indicate that cocoa exerts neuroprotective effects suggesting a novel possible strategy to prevent or, at least, mitigate neurodegenerative disorders, such as PD.

Sleep duration irregularity is associated with elevated blood pressure in young adults

Sleep irregularity (i.e., highly variable sleep patterns) is an emerging risk factor for cardiometabolic disease. Though irregular sleep patterns are common among young adults, the cardiometabolic health (CMH) repercussions of sleep irregularity in this population are unclear. We examined associations between sleep duration and irregularity with measures of CMH in 44 (24 M/20 F, 23 ± 5y, BMI 26 ± 4 kg/m², blood pressure (BP): 125/71 ± 14/9 mmHg) young adults. Participants wore actigraphy monitors for seven-days and sleep duration irregularity was operationalized as the standard deviation of nightly sleep duration (sleep SD). CMH variables of interest included brachial and aortic BP, arterial stiffness (cf-PWV), augmentation index (AIx75), and fasting blood glucose and lipids. Associations between sleep duration and sleep SD with CMH variables were assessed via correlations adjusted for sex and BMI. Sleep duration generally was not associated with CMH indices. However, sleep SD was associated with brachial systolic (r = 0.433, p = .027) and diastolic BP (r = 0.415, p = .035). Similarly, sleep duration SD was associated with aortic systolic BP (r = 0.447, p = .022). Our findings show that sleep irregularity, but not duration, is associated with higher brachial and central BP in young adults.Abbreviations: AIx75: augmentation index at a heart rate of 75 beats per minute; BP: blood pressure; CMH: cardiometabolic health; cf-PWV: carotid-femoral pulse wave velocity; DXA: dual x-ray absorptiometry; mg/dl: milligrams per deciliter; PWA: pulse wave analysis; PWV: pulse wave velocity; sleep duration SD: standard deviation of nightly sleep duration.

Acute effects of cocoa flavanols on visual working memory: maintenance and updating

BACKGROUND

Consumption of cocoa flavanols may have acute physiological effects on the brain due to their ability to activate nitric oxide synthesis. Nitric oxide mediates vasodilation, which increases cerebral blood flow, and can also act as a neurotransmitter.

OBJECTIVES

This study aimed to examine whether cocoa flavanols have an acute influence on visual working memory (WM).

METHODS

Two separate randomised, double-blind, placebo-controlled, counterbalanced crossover experiments were conducted on normal healthy young adult volunteers (N_Exp1 = 48 and N_Exp2 = 32, gender-balanced). In these experiments, 415 mg of cocoa flavanols were administered to test their acute effects on visual working memory. In the first experiment, memory recall precision was measured in a task that required only passive maintenance of grating orientations in WM. In the second experiment, recall was measured after active updating (mental rotation) of WM contents. Habitual daily flavanols intake, body mass index, and gender were also considered in the analysis.

RESULTS

The results suggested that neither passive maintenance in visual WM nor active updating of WM were acutely enhanced by consumption of cocoa flavanols. Exploratory analyses with covariates (body mass index and daily flavanols intake), and the between-subjects factor of gender also showed no evidence for effects of cocoa flavanols, neither in terms of reaction time, nor accuracy.

CONCLUSIONS

Overall, cocoa flavanols did not improve visual working memory recall performance during maintenance, nor did it improve recall accuracy after memory updating.

Intake of Products Containing Anthocyanins, Flavanols, and Flavanones, and Cognitive Function: A Narrative Review

The purpose of this review is to examine human research studies published within the past 6 years which evaluate the role of anthocyanin, flavanol, and flavanone consumption in cognitive function, and to discuss potential mechanisms of action underlying any observed benefits. Evidence to date suggests the consumption of flavonoid-rich foods, such as berries and cocoa, may have the potential to limit, or even reverse, age-related declines in cognition. Over the last 6 years, the flavonoid subgroups of anthocyanins, flavanols, and flavanones have been shown to be beneficial in terms of conferring neuroprotection. The mechanisms by which flavonoids positively modulate cognitive function are yet to be fully elucidated. Postulated mechanisms include both direct actions such as receptor activation, neurotrophin release and intracellular signaling pathway modulation, and indirect actions such as enhancement of cerebral blood flow. Further intervention studies conducted in diverse populations with sufficient sample sizes and long durations are required to examine the effect of consumption of flavonoid groups on clinically relevant cognitive outcomes. As populations continue to focus on adopting healthy aging strategies, dietary interventions with flavonoids remains a promising avenue for future research. However, many questions are still to be answered, including identifying appropriate dosage, timeframes for intake, as well as the best form of flavonoids, before definitive conclusions can be drawn about the extent to which their consumption can protect the aging brain.

Aqueous Extract of Cocoa Phenolic Compounds Protects Differentiated Neuroblastoma SH-SY5Y Cells from Oxidative Stress

Cocoa is a rich source of polyphenols, especially flavanols and procyanidin oligomers, with antioxidant properties, providing protection against oxidation and nitration. Cocoa phenolic compounds are usually extracted with methanol/ethanol solvents in order to obtain most of their bioactive compounds; however, aqueous extraction seems more representative of the physiological conditions. In this study, an aqueous extract of cocoa powder has been prepared and chemically characterized, and its potential protective effect against chemically-induced oxidative stress has been tested in differentiated human neuroblastoma SH-SY5Y cells. Neuronal-like cultured cells were pretreated with realistic concentrations of cocoa extract and its major monomeric flavanol component, epicatechin, and then submitted to oxidative stress induced by a potent pro-oxidant. After one hour, production of reactive oxygen species was evaluated by two different methods, flow cytometry and in situ fluorescence by a microplate reader. Simultaneously, reduced glutathione and antioxidant defense enzymes glutathione peroxidase and glutathione reductase were determined and the results used for a comparative analysis of both ROS (reactive oxygen species) methods and to test the chemo-protective effect of the bioactive products on neuronal-like cells. The results of this approach, never tested before, validate both analysis of ROS and indicate that concentrations of an aqueous extract of cocoa phenolics and epicatechin within a physiological range confer a significant protection against oxidative insult to neuronal-like cells in culture.

Hydroalcoholic extract from Abelmoschus manihot (Linn.) Medicus flower reverses sleep deprivation-evoked learning and memory deficit

Previous researches have indicated that sleep plays a vital role in cognitive functions. Sleep deprivation (SD) causes learning and memory damage, which is associated with oxidative stress. This study was performed to investigate the neuroprotective effects of an extract of Abelmoschus manihot flower (EAM) against memory deficit induced by SD in mice. The SD model was evoked by multiple platform method for 5 days, successively. The learning and memory-improving effects of EAM were assessed by behavioral trials and the underlying mechanism was investigated by measuring the oxidative stress alteration. Our findings indicated that the SD-induced memory deficit and the EAM treatment improved the cognitive functions of mice in the object location recognition test and passive avoidance task. In addition, EAM effectively improved the activities of the antioxidant enzyme, decreased the content of malondialdehyde (MDA), and restored the protein expression of the brain-derived neurotrophic factor (BDNF), tyrosine kinase B (TrkB) and glutamate receptor 1 (GluR1) in brain tissues. In conclusion, EAM could improve the SD-evoked learning and memory impairments. The possible underlying mechanisms of EAM may be related to its antioxidant capacity and enhanced BDNF/TrkB/GluR1 levels in the hippocampal memory.

Effects of sleep deprivation on endothelial function in adult humans: a systematic review

Sleep deprivation is highly prevalent and is associated with increased cardiovascular disease (CVD) morbidity and mortality. Age-related alterations in sleep and chronobiology may exaggerate CVD susceptibility in older individuals. The mechanisms responsible for the association between sleep deprivation and CVD are not fully understood, but endothelial dysfunction may play a central role. Our objective was to conduct a systematic literature review to evaluate the evidence on the effects of sleep deprivation on endothelial function (EF). This review adhered to the PRISMA guidelines and was pre-registered with PROSPERO (#CRD42020192485, 07/24/2020). We searched PubMed, Web of Science, Embase, and Cochrane Library for articles published through May 1, 2020. Eligibility criteria included publication in English and use of well-established EF methodologies in adult humans. Two investigators independently performed the literature search, study selection, data extraction, risk-of-bias assessment, and qualitative data synthesis. Out of 3571 articles identified, 24 articles were included in the systematic review. Main findings include the following: (1) shorter sleep duration is associated with lower macrovascular EF; (2) not sleeping 7-9 h/night is linked with impaired microvascular EF; (3) sleep restriction impairs micro- and macrovascular EF; (4) acute total sleep deprivation impairs micro- and macrovascular EF but data on macrovascular EF are less consistent; and (5) shift work impairs macrovascular EF. In conclusion, sleep deprivation impairs EF, which may explain the link between insufficient sleep and CVD. Future investigations should fully elucidate the underlying mechanisms and develop strategies to combat the adverse endothelial effects of sleep deprivation across the lifespan.

The impact of the 24-h movement spectrum on vascular remodeling in older men and women: a review

Aging is associated with increased risk of cardiovascular and cerebrovascular events, which are preceded by early, negative remodeling of the vasculature. Low physical activity is a well-established risk factor associated with the incidence and development of disease. However, recent physical activity literature indicates the importance of considering the 24-h movement spectrum. Therefore, the purpose of this review was to examine the impact of the 24-h movement spectrum, specifically physical activity (aerobic and resistance training), sedentary behavior, and sleep, on cardiovascular and cerebrovascular outcomes in older adults, with a focus on recent evidence (<10 yr) and sex-based considerations. The review identifies that both aerobic training and being physically active (compared with sedentary) are associated with improvements in endothelial function, arterial stiffness, and cerebrovascular function. Additionally, there is evidence of sex-based differences in endothelial function: a blunted improvement in aerobic training in postmenopausal women compared with men. While minimal research has been conducted in older adults, resistance training does not appear to influence arterial stiffness. Poor sleep quantity or quality are associated with both impaired endothelial function and increased arterial stiffness. Finally, the review highlights mechanistic pathways involved in the regulation of vascular and cerebrovascular function, specifically the balance between pro- and antiatherogenic factors, which mediate the relationship between the 24-h movement spectrum and vascular outcomes. Finally, this review proposes future research directions: examining the role of duration and intensity of training, combining aerobic and resistance training, and exploration of sex-based differences in cardiovascular and cerebrovascular outcomes.

Improvement of Executive Function after Short-Term Administration of an Antioxidants Mix Containing Bacopa, Lycopene, Astaxanthin and Vitamin B12: The BLAtwelve Study

During the last few years increasing interest has been focused on antioxidants as potentially useful agents in the prevention of the onset and progression of cognitive dysfunction. In this randomized, double-blind, controlled, parallel arm study, the effects of daily consumption of an antioxidant mix on cognitive function in healthy older adults were evaluated. After a 1 week run-in period, 80 subjects aged 60 years or more, and with no evidence of cognitive dysfunction, were randomly allocated to a mix of four bioactive compounds (bacopa, lycopene, astaxanthin, and vitamin B12) or matched placebo, taken orally once a day for 8 weeks. The primary objective of the study was to evaluate the changes in trial making test (TMT) scores from baseline to 8 weeks of treatment, analyzed in the following hierarchical order: TMT-B, TMT-A, and TMT-B minus TMT-A. TMT-B increased in the control group (+3.46 s) and decreased in the active group (−17.63 s). The treatment difference was −21.01 s in favor of the active group (95% C.I. −26.80 to −15.2, p < 0.0001). The decrease in TMT-A was significantly higher in the active group (−6.86 s) than in the control group (−0.37 s). TMT-B minus TMT-A increased in the control group (+3.84 s) and decreased in the active group (−10.46 s). The increase in letter fluency in the verbal fluency test (VFT) was also significantly higher in the active group and statistically significant (+5.28 vs. +1.07 words; p < 0.001). Our findings provide encouraging evidence that regular dietary supplementation with bacopa, lycopene, astaxanthin, and vitamin B12 may be an effective dietary approach for counteracting cognitive changes associated with brain aging.

Non-pharmacological Strategies Against Systemic Inflammation: Molecular Basis and Clinical Evidence

Systemic inflammation is a common denominator to a variety of cardiovascular (CV) and non-CV diseases and relative risk factors, including hypertension and its control, metabolic diseases, rheumatic disorders, and those affecting the gastrointestinal tract. Besides medications, a non-pharmacological approach encompassing lifestyle changes and other complementary measures is mentioned in several updated guidelines on the management of these conditions. We performed an updated narrative review on the mechanisms behind the systemic impact of inflammation and the role of non-pharmacological, complementary measures centered on lowering systemic phlogosis for preserving or restoring a good global health. The central role of genetics in shaping the immune response is discussed in conjunction with that of the microbiome, highlighting the interdependence and mutual influences between the human genome and microbial integrity, diversity, and functions. Several plausible strategies to modulate inflammation and restore balanced crosstalk between the human genome and the microbiome are then recapitulated, including dietary measures, active lifestyle, and other potential approaches to manipulate the resident microbial community. To date, evidence from high-quality human studies is sparse to allow the unconditioned inclusion of understudied, though plausible solutions against inflammation into public health strategies for global wellness. This gap claims further focused, well-designed research targeted at unravelling the mechanisms behind future personalized medicine.

Effect of Cocoa and Cocoa Products on Cognitive Performance in Young Adults

Increasing evidence support a beneficial role of cocoa and cocoa products on human cognition, particularly in aging populations and patients at risk. However, thorough reviews on the efficacy of cocoa on brain processes in young adults do not exist precisely due to the limited number of studies in the matter. Thus, the aim of this study was to summarize the findings on the acute and chronic effects of cocoa administration on cognitive functions and brain health in young adults. Web of Science and PubMed databases were used to search for relevant trials. Human randomized controlled studies were selected according to PRISMA guidelines. Eleven intervention studies that involved a total of 366 participants investigating the role of cocoa on cognitive performance in children and young adults (average age ≤ 25 years old) were finally selected. Findings from individual studies confirm that acute and chronic cocoa intake have a positive effect on several cognitive outcomes. After acute consumption, these beneficial effects seem to be accompanied with an increase in cerebral blood flow or cerebral blood oxygenation. After chronic intake of cocoa flavanols in young adults, a better cognitive performance was found together with increased levels of neurotrophins. This systematic review further supports the beneficial effect of cocoa flavanols on cognitive function and neuroplasticity and indicates that such benefits are possible in early adulthood.

Effects of cocoa-rich chocolate on cognitive performance in postmenopausal women. A randomised clinical trial

OBJECTIVES

The aim of this research was to evaluate the effects of adding 10 g of cocoa-rich chocolate (99%) to the habitual diet on cognitive performance in postmenopausal women.

METHODS

Following a randomised controlled parallel clinical trial, a total of 140 postmenopausal women aged 50-64 were recruited. The intervention group (n = 73) consumed daily 10 g of chocolate (99% cocoa) in addition to their usual food intake for 6 months, whereas the control group (n = 67) did not receive any intervention. Attention and executive functions, verbal memory, working memory, phonological fluency, category fluency and clinical variables were assessed at baseline and 6 months.

RESULTS

Trail Making Test B execution time showed a decreased of -12.08 s (95% CI: -23.99, -0.18; p = 0.047) in the intervention group compared to the control group, after adjusting for age, educational level, time elapsed from the beginning of menopause and daily energy consumption (Cohen's d = -0.343). Attention, immediate or delayed verbal memory, phonological or category fluency, and working memory remained unchanged.

CONCLUSIONS

The consumption of cocoa-rich (99%) chocolate in addition to the habitual diet could be related to a slight improvement in cognitive performance regarding cognitive flexibility and processing speed in postmenopausal women, with no changes in the rest of the cognitive performance variables evaluated.Trial registration: This clinical trial has been registered at clinicaltrials.gov as NCT03492983.

Sleep deprivation and endothelial function: reconciling seminal evidence with recent perspectives

Sleep is critical for the maintenance of physiological homeostasis and, as such, inadequate sleep beckons a myriad of pathologies. Sleep deprivation is a growing health concern in contemporary society since short sleep durations are associated with increased cardiovascular disease risk and atherosclerotic plaque development. Vascular endothelial dysfunction is an antecedent to atherosclerosis and cardiovascular disease. Herein, we review seminal literature indicating that short sleep durations attenuate endothelial function and explore more recent evidence indicating that sleep deprivation perturbs autonomic balance and the circadian rhythmicity of peripheral vascular clock components. We further examine literature that indicates a mechanistic link between short sleep duration and endothelial dysfunction and subsequent morbidity. Understanding the mechanisms that regulate endothelial function in the context of sleep deprivation facilitates the development and optimization of interventions, such as exercise, that mitigate the ramifications of inadequate sleep on vascular function and cardiovascular health.Listen to this article's corresponding podcast at https://ajpheart.podbean.com/e/sleep-deprivation-and-endothelial-function/.

Is There Such a Thing as "Anti-Nutrients"? A Narrative Review of Perceived Problematic Plant Compounds

Plant-based diets are associated with reduced risk of lifestyle-induced chronic diseases. The thousands of phytochemicals they contain are implicated in cellular-based mechanisms to promote antioxidant defense and reduce inflammation. While recommendations encourage the intake of fruits and vegetables, most people fall short of their target daily intake. Despite the need to increase plant-food consumption, there have been some concerns raised about whether they are beneficial because of the various ‘anti-nutrient’ compounds they contain. Some of these anti-nutrients that have been called into question included lectins, oxalates, goitrogens, phytoestrogens, phytates, and tannins. As a result, there may be select individuals with specific health conditions who elect to decrease their plant food intake despite potential benefits. The purpose of this narrative review is to examine the science of these ‘anti-nutrients’ and weigh the evidence of whether these compounds pose an actual health threat.

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

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

Effect of cocoa on the brain and gut in healthy subjects: a randomised controlled trial

Dark chocolate is claimed to have effects on gastrointestinal function and to improve well-being. This randomised controlled study tested the hypothesis that cocoa slows gastric emptying and intestinal transit. Functional brain imaging identified central effects of cocoa on cortical activity. Healthy volunteers (HV) ingested 100 g dark (72 % cocoa) or white (0 % cocoa) chocolate for 5 d, in randomised order. Participants recorded abdominal symptoms and stool consistency by the Bristol Stool Score (BSS). Gastric emptying (GE) and intestinal and colonic transit time were assessed by scintigraphy and marker studies, respectively. Combined positron emission tomography-computed tomography (PET-CT) imaging assessed regional brain activity. A total of sixteen HV (seven females and nine males) completed the studies (mean age 34 (21-58) years, BMI 22·8 (18·5-26·0) kg/m2). Dark chocolate had no effect on upper gastrointestinal function (GE half-time 82 (75-120) v. 83 (60-120) min; P=0·937); however, stool consistency was increased (BSS 3 (3-5) v. 4 (4-6); P=0·011) and there was a trend to slower colonic transit (17 (13-26) v. 21 (15-47) h; P=0·075). PET-CT imaging showed increased [18F]fluorodeoxyglucose (FDG) in the visual cortex, with increased FDG uptake also in somatosensory, motor and pre-frontal cortices (P&lt;0·001). In conclusion, dark chocolate with a high cocoa content has effects on colonic and cerebral function in HV. Future research will assess its effects in patients with functional gastrointestinal diseases with disturbed bowel function and psychological complaints.

Higher chocolate intake is associated with longer telomere length among adolescents

BACKGROUND

Chocolate intake has shown cardiometabolic health benefits. Whether chocolate has any effect on cellular aging remains unknown. We aimed to test the hypothesis that higher chocolate intake is associated with longer leukocyte telomere length (LTL) in adolescents.

METHODS

A total of 660 adolescents (aged 14-18 years) were included in the analysis. The chocolate intake was assessed by 7-day, 24-h dietary recalls and split into three groups, which were none, <2 servings/week, and 2 servings/week or more. LTL (T/S ratio) was determined by a modified quantitative polymerase chain reaction-based assay.

RESULTS

Among the 660 adolescents, 58% did not take any chocolate, 25% consumed <2 servings/week, and 17% consumed ≥2 servings/week. Compared to non-consumers, adolescents who consumed chocolate of ≥2 servings/week had 0.27 standard deviation (SD) longer LTL (p = 0.014). Higher chocolate consumption was associated with increased apolipoprotein A1 (ApoA1) (p = 0.038) and ApoA1/high-density lipoprotein (HDL) (p = 0.046). Moreover, higher ApoA1/HDL levels were correlated with longer LTL (p = 0.026).

CONCLUSION

Adolescents who consume 2 servings/week or more of chocolate candy have longer LTL compared with non-consumers, and ApoA1/HDL pathway may be involved in this relationship.

Sleep Restriction Effects on BP: Systematic Review & Meta-analysis of RCTs

This systematic review and meta-analysis aimed to examine the effect of sleep restriction on blood pressure (BP) among healthy adults. Randomized controlled trials (RCTs) using partial sleep deprivation were included. The pooled effect size was calculated by the inverse variance method, and forest plot was used. Six studies were included (n = 10-43). Only one study obtained continuous BP readings. Overall, sleep restriction did not result in significant changes in systolic blood pressure (SBP) or diastolic blood pressure (DBP) and heart rate (HR). The respective weighted mean difference (MD) was 1.0 mmHg (95%CI, -2.3-4.2; p = 0.57), -0.4 mmHg (95%CI, -3.2-2.4; p = 0.80), and 2.0 bpm (95%CI, -2.2-6.2; p = 0.34). There is preliminary evidence suggesting that sleep restriction might affect sympathetic/parasympathetic modulation of cardiac autonomy and the inflammatory system. In this review, we did not find significant effects of sleep restriction on BP or HR measured by cross-sectional methods. More studies are warranted to confirm these findings by using continuous monitoring.

Corticotropin-releasing hormone is significantly upregulated in the mouse paraventricular nucleus following a single oral dose of cinnamtannin A2 as an (-)-epicatechin tetramer

Cinnamtannin A2, an (−)-epicatechin tetramer, was reported to have potent physiological activity. Cinnamtannin A2 is rarely absorbed from the gastrointestinal tract into the blood and the mechanisms of its beneficial activities are unknown. Cinnamtannin A2 reported to increase sympathetic nervous activity, which was induced by various stressors. In present study, we examined the stress response in the mouse paraventricular nucleus following a single oral dose of cinnamtannin A2 by monitoring mRNA expression of corticotropin-releasing hormone (CRH) and c-fos using in situ hybridization. Corticotropin-releasing hormone mRNA showed a tendency to increase at 15 min and significantly increased at 60 min following a single oral administration of 100 µg/kg cinnamtannin A2. After a single dose of 10 µg/kg cinnamtannin A2, there was significant upregulation of CRH mRNA at 60 min. These results suggested that cinnamtannin A2 was recognized as a stressor in central nervous system and this may lead to its beneficial effects on circulation and metabolism.

Corticotropin-releasing hormone is significantly upregulated in the mouse paraventricular nucleus following a single oral dose of cinnamtannin A2 as an (-)-epicatechin tetramer

Cinnamtannin A2, an (-)-epicatechin tetramer, was reported to have potent physiological activity. Cinnamtannin A2 is rarely absorbed from the gastrointestinal tract into the blood and the mechanisms of its beneficial activities are unknown. Cinnamtannin A2 reported to increase sympathetic nervous activity, which was induced by various stressors. In present study, we examined the stress response in the mouse paraventricular nucleus following a single oral dose of cinnamtannin A2 by monitoring mRNA expression of corticotropin-releasing hormone (CRH) and c-fos using in situ hybridization. Corticotropin-releasing hormone mRNA showed a tendency to increase at 15 min and significantly increased at 60 min following a single oral administration of 100 µg/kg cinnamtannin A2. After a single dose of 10 µg/kg cinnamtannin A2, there was significant upregulation of CRH mRNA at 60 min. These results suggested that cinnamtannin A2 was recognized as a stressor in central nervous system and this may lead to its beneficial effects on circulation and metabolism.

Bridging the Reciprocal Gap between Sleep and Fruit and Vegetable Consumption: A Review of the Evidence, Potential Mechanisms, Implications, and Directions for Future Work

A substantial burden of disease and mortality globally is attributable to both sleep disruption and low intakes of fruit and vegetable (FV) and there is increasing mechanistic and epidemiological evidence to support a reciprocal relationship between the two. This review provides an overview of experimental and observational studies assessing the relations between sleep and FV consumption from 52 human adult studies. Experimental studies are currently limited and show inconsistent results. Observational studies support a non-linear association with adults sleeping the recommended 7–9 hours/day having the highest intakes of FV. The potential mechanisms linking sleep and FV consumption are highlighted. Disrupted sleep influences FV consumption through homeostatic and non-homeostatic mechanisms. Conversely, FV consumption may influence sleep through polyphenol content via several potential pathways. Few human experimental studies have examined the effects of FV items and their polyphenols on sleep and there is a need for more studies to address this. An appreciation of the relationship between sleep and FV consumption may help optimize sleep and FV consumption and may reduce the burden of chronic diseases. This review provides implications for public health and directions for future work.

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

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

More than just caffeine: psychopharmacology of methylxanthine interactions with plant-derived phytochemicals

In general, preparations of coffee, teas, and cocoa containing high levels of polyphenols, L-theanine and other bioactive compounds selectively enhance mood and cognition effects of caffeine. This review summarizes the bioactive components of commonly consumed natural caffeine sources (e.g. guayusa, mate and camellia teas, coffee and cocoa) and analyzes the psychopharmacology of constituent phytochemicals: methylxanthines, polyphenols, and L-theanine. Acute and chronic synergistic effects of these compounds on mood and cognition are compared and discussed. Specific sets of constituent compounds such as polyphenols, theobromine and L-theanine appear to enhance mood and cognition effects of caffeine and alleviate negative psychophysiological effects of caffeine. However, more research is needed to identify optimal combinations and ratios of caffeine and phytochemicals for enhancement of cognitive performance.

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

INTRODUCTION

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

METHODS AND ANALYSIS

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

ETHICS AND DISSEMINATION

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

Daily Consumption of Chocolate Rich in Flavonoids Decreases Cellular Genotoxicity and Improves Biochemical Parameters of Lipid and Glucose Metabolism

In recent years, the incidence of atherosclerotic cardiovascular disease, obesity, and diabetes has increased largely worldwide. In the present work, we evaluated the genoprotective effect of the consumption of flavonoids-rich chocolate on 84 young volunteers. Biochemical indicators related to the prevention and treatment of cardiovascular risk and metabolic syndrome were also determined. A randomized, placebo-controlled, double-blind study was performed in the Autonomous University of Baja California. The treatments comprised the daily consumption of either 2 g of dark chocolate containing 70% cocoa, or 2 g of milk chocolate, for 6 months. The total amount of phenolic compounds and flavonoids was determined in both types of chocolate. Anthropometrical and Biochemical parameters were recorded prior to and after the study. The evaluation of the genotoxicity in buccal epithelial cells was performed throughout the duration of the study. Flavonoids from cocoa in dark chocolate significantly prevented DNA damage, and improved the nucleus integrity of cells. This effect could be related to the antioxidant capacity of the dark chocolate that decreased cellular stress. Biochemical parameters (total cholesterol, triglycerides, and LDL-cholesterol level in blood) and anthropometrical parameters (waist circumference) were improved after six months of daily intake of 2 g of dark chocolate with a 70% of cocoa.

Single oral administration of flavan 3-ols induces stress responses monitored with stress hormone elevations in the plasma and paraventricular nucleus

We previously confirmed that postprandial alterations in the circulation and metabolism after a single oral dose of flavan 3-ols (mixture of catechin and catechin oligomers) were involved in an increase in sympathetic nervous activity. However, it is well known that, in response to various stresses, activation of the hypothalamic-pituitary-adrenal (HPA) axis occurs together with sympathetic nerve activity, which is associated with activation of the sympathetic-adrenal-medullary (SAM) axis. In this study, we examined whether the HPA axis was activated after a single dose of flavan 3-ols. We administered an oral dose of 10 or 50 mg/kg flavan 3-ols to male ICR mice, removed the brains, and fixed them in paraformaldehyde-phosphate buffer. Other animals that were treated similarly were decapitated, and blood was collected. In the paraventricular nucleus (PVN), c-fos mRNA expression increased significantly at 15 min after administration of either 10 or 50 mg/kg flavan 3-ols. Corticotropin-releasing hormone (CRH) mRNA expression levels significantly increased at 240 min after administration of 10 mg/kg flavan 3-ols, and at 60 min after administration of 50 mg/kg flavan 3-ols. Plasma corticosterone levels were also significantly increased at 240 min after ingestion of 50 mg/kg flavan 3-ols. In this experiment, we confirmed that the ingestion of flavan 3-ols acted as a stressor in mammals with activation both the SAM and HPA axes.

The Impact of Epicatechin on Human Cognition: The Role of Cerebral Blood Flow

Epicatechin is a monomeric flavanol found in food sources such as tea, apples, berries and cocoa. A number of large-scale epidemiological studies have demonstrated an association between the consumption of these foods and cognitive function, as well as improved blood flow. The aim of this review is to summarise the evidence from intervention studies to clarify the effect of epicatechin on cognition and to consider the role of increased cerebral blood flow as a mechanism for any effects. The effects of epicatechin as consumed in cocoa are, therefore, reviewed here as this represents the only dietary source where it is purported to be the major active component. Our main findings are that a) the positive modulation of tasks that involve memory, executive function and processing speed in older adults; b) the cognitive benefits are more often shown in studies containing more than 50 mg epicatechin/day; and c) all studies with a duration of 28 days or longer in populations >50 years old demonstrate a cognitive improvement. However, as highlighted by this review, it is not currently possible to attribute effects solely to epicatechin without consideration of synergies. In order to overcome this issue, further studies examining the cognitive effects of epicatechin in isolation are required. The role of cerebral blood flow also requires further investigation through simultaneous measurement alongside cognitive function.

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

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

The acute effects of cocoa flavanols on temporal and spatial attention

In this study, we investigated how the acute physiological effects of cocoa flavanols might result in specific cognitive changes, in particular in temporal and spatial attention. To this end, we pre-registered and implemented a randomized, double-blind, placebo- and baseline-controlled crossover design. A sample of 48 university students participated in the study and each of them completed the experimental tasks in four conditions (baseline, placebo, low dose, and high-dose flavanol), administered in separate sessions with a 1-week washout interval. A rapid serial visual presentation task was used to test flavanol effects on temporal attention and integration, and a visual search task was similarly employed to investigate spatial attention. Results indicated that cocoa flavanols improved visual search efficiency, reflected by reduced reaction time. However, cocoa flavanols did not facilitate temporal attention nor integration, suggesting that flavanols may affect some aspects of attention, but not others. Potential underlying mechanisms are discussed.

Impact of chocolate liquor on vascular lesions in apoE-knockout mice

Cocoa polyphenols are thought to reduce the risk of cardiovascular diseases. Thus, cocoa-containing foods may have significant health benefits. Here, we studied the impact of chocolate liquor on vascular lesion development and plaque composition in a mouse model of atherosclerosis. Apolipoprotein E (apoE)-knockout mice were assigned to two groups and fed a Western diet that contained 250 g/kg of either chocolate liquor or a polyphenol-free isoenergetic control paste for 16 weeks. In addition to fat, protein, and fibers, the chocolate liquor contained 2 g/kg of polyphenols. Compared with the control group, mice fed the chocolate liquor had larger plaque areas in the descending aorta and aortic root, which were attributed to a higher mass of vascular smooth muscle cells (VSMCs) and collagen. Vascular lipid deposits and calcification areas did not differ between the two groups. The aortic tissue level of interleukin-6 (IL-6) mRNA was 5-fold higher in the mice fed chocolate liquor than in the control mice. Chocolate-fed mice exhibited an increased hepatic saturated to polyunsaturated fatty acid ratio than the controls. Although the chocolate liquor contained 14 µg/kg of vitamin D₂, the chocolate liquor-fed mice did not have measurable 25-hydroxyvitamin D₂ in the serum. These mice even showed a 25% reduction in the level of 25-hydroxyvitamin D₃ compared with the control mice. Overall, present data may contribute to our understanding how chocolate constituents can impact vascular lesion development.

Enhancing Human Cognition with Cocoa Flavonoids

Enhancing cognitive abilities has become a fascinating scientific challenge, recently driven by the interest in preventing age-related cognitive decline and sustaining normal cognitive performance in response to cognitively demanding environments. In recent years, cocoa and cocoa-derived products, as a rich source of flavonoids, mainly the flavanols sub-class, have been clearly shown to exert cardiovascular benefits. More recently, neuromodulation and neuroprotective actions have been also suggested. Here, we discuss human studies specifically aimed at investigating the effects of acute and chronic administration of cocoa flavanols on different cognitive domains, such as executive functions, attention and memory. Through a variety of direct and indirect biological actions, in part still speculative, cocoa and cocoa-derived food have been suggested to possess the potential to counteract cognitive decline and sustain cognitive abilities, particularly among patients at risk. Although still at a preliminary stage, research investigating the relations between cocoa and cognition shows dose-dependent improvements in general cognition, attention, processing speed, and working memory. Moreover, cocoa flavanols administration could also enhance normal cognitive functioning and exert a protective role on cognitive performance and cardiovascular function specifically impaired by sleep loss, in healthy subjects. Together, these findings converge at pointing to cocoa as a new interesting nutraceutical tool to protect human cognition and counteract different types of cognitive decline, thus encouraging further investigations. Future research should include complex experimental designs combining neuroimaging techniques with physiological and behavioral measures to better elucidate cocoa neuromodulatory properties and directly compare immediate versus long-lasting cognitive effects.

Effect of cocoa on blood pressure

BACKGROUND

High blood pressure is an important risk factor for cardiovascular disease, contributing 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. Here we update previous meta-analyses on the effect of cocoa on blood pressure.

OBJECTIVES

To assess the effects on blood pressure of chocolate or cocoa products versus low-flavanol products or placebo in adults with or without hypertension when consumed for two weeks or longer.

SEARCH METHODS

This is an updated version of the review initially published in 2012. In this updated version, we searched the following electronic databases from inception to November 2016: Cochrane Hypertension Group Specialised Register, CENTRAL, MEDLINE and Embase. We also searched international trial registries, and the reference lists of review articles and included trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) 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 review authors independently extracted data and assessed the risks of bias in each trial. We conducted random-effects meta-analyses on the included studies using Review Manager 5. We explored heterogeneity with subgroup analyses by baseline blood pressure, flavanol content of control group, blinding, age and duration. Sensitivity analyses explored the influence of unusual study design.

MAIN RESULTS

Thirty-five trials (including 40 treatment comparisons) met the inclusion criteria. Of these, we added 17 trials (20 treatment comparisons) to the 18 trials (20 treatment comparisons) in the previous version of this updated review.Trials provided participants with 30 to 1218 mg of flavanols (mean = 670 mg) in 1.4 to 105 grams of cocoa products per day in the active intervention group. The control group received either a flavanol-free product (n = 26 treatment comparisons) or a low-flavanol-containing cocoa powder (range 6.4 to 88 mg flavanols (mean = 55 mg, 13 treatment comparisons; 259 mg, 1 trial).Meta-analyses of the 40 treatment comparisons involving 1804 mainly healthy participants revealed a small but statistically significant blood pressure-reducing effect of flavanol-rich cocoa products compared with control in trials of two to 18 weeks duration (mean nine weeks):Mean difference systolic blood pressure (SBP) (95% confidence interval (CI): -1.76 (-3.09 to -0.43) mmHg, P = 0.009, n = 40 treatment comparisons, 1804 participants;Mean difference diastolic blood pressure (DBP) (95% CI): -1.76 (-2.57 to -0.94) mmHg, P < 0.001, n = 39 treatment comparisons, 1772 participants.Baseline blood pressure may play a role in the effect of cocoa on blood pressure. While systolic blood pressure was reduced significantly by 4 mmHg in hypertensive people (n = 9 treatment comparisons, 401 participants), and tended to be lowered in prehypertensive people (n= 8 treatment comparisons, 340 participants), there was no significant difference in normotensive people (n = 23 treatment comparisons, 1063 participants); however, the test for subgroup differences was of borderline significance (P = 0.08; I² = 60%), requiring further research to confirm the findings.Subgroup meta-analysis by blinding suggested a trend towards greater blood pressure reduction in unblinded trials compared to double-blinded trials, albeit statistically not significant. Further research is needed to confirm whether participant expectation may influence blood pressure results. Subgroup analysis by type of control (flavanol-free versus low-flavanol control) did not reveal a significant difference.Whether the age of participants plays a role in the effect of cocoa on blood pressure, with younger participants responding with greater blood pressure reduction, needs to be further investigated.Sensitivity analysis excluding trials with authors employed by trials sponsoring industry (33 trials, 1482 participants) revealed a small reduction in effect size, indicating some reporting bias.Due to the remaining heterogeneity, which we could not explain in terms of blinding, flavanol content of the control groups, age of participants, or study duration, we downgraded the quality of the evidence from high to moderate.Results of subgroup analyses should be interpreted with caution and need to be confirmed or refuted in trials using direct randomised comparisons.Generally, cocoa products were highly tolerable, with adverse effects including gastrointestinal complaints and nausea being reported by 1% of participants in the active cocoa intervention group and 0.4% of participants in the control groups (moderate-quality evidence).

AUTHORS' CONCLUSIONS

This review provides moderate-quality evidence that flavanol-rich chocolate and cocoa products cause a small (2 mmHg) blood pressure-lowering effect in mainly healthy adults in the short term.These findings are limited by the heterogeneity between trials, which could not be explained by prespecified subgroup analyses, including blinding, flavanol content of the control groups, age of participants, or study duration. However, baseline blood pressure may play a role in the effect of cocoa on blood pressure; subgroup analysis of trials with (pre)hypertensive participants revealed a greater blood pressure-reducing effect of cocoa compared to normotensive participants with borderline significance.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.