Effects of theobromine and caffeine on mood and vigilance

A systematic review and meta-analysis of the acute effect of caffeine on attention

RATIONALE

Although there is broad agreement that caffeine provides an acute improvement in attention in the normal population, estimates of effect size vary and the relationship between dose and effect is unclear.

OBJECTIVE

To examine the acute effect of caffeine on attention in a systematic review and meta-analysis.

METHODS

PsycINFO, PubMed, and Scopus were searched for records published in English with no limits on the year of publication. Studies were included if they were randomized, double-blinded, placebo-controlled, and if they examined the acute effect of pure caffeine on behavioral tests of attention in rested, healthy adults. For every included trial, eligible outcomes were extracted and aggregated to form one composite standardized mean difference (SMD; Hedges' adjusted g) for reaction time and one for accuracy. The SMDs were then combined in random-effects meta-analyses. Additionally, several subgroup analyses were conducted, including meta-regressions on dose-response relationships.

RESULTS

Thirty-one trials with a total of 1455 participants were included in the meta-analysis. Significant effects in favor of caffeine were found for both accuracy, g = 0.27, and reaction time, g = 0.28. Subgroup analyses showed that higher doses of caffeine (≥ 200 mg) improved both reaction time and accuracy more than lower doses, but whereas a positive linear dose-response relationship was found for reaction time, a quadratic relationship was found for accuracy. The effect of caffeine was not related to differences in habitual caffeine consumption, task complexity, or which attention network was taxed.

CONCLUSION

The current evidence shows that in the normal population, caffeine acutely enhances attention by improving both reaction time and accuracy. However, whereas higher doses continue to enhance reaction time, accuracy improves only up to a certain point before declining.

Plant Alkaloids as Promising Anticancer Compounds with Blood-Brain Barrier Penetration in the Treatment of Glioblastoma: In Vitro and In Vivo Models

Glioblastoma (GBM) is one of the most invasive central nervous system tumors, with rising global incidence. Therapy resistance and poor prognosis highlight the urgent need for new anticancer drugs. Plant alkaloids, a largely unexplored yet promising class of compounds, have previously contributed to oncology treatments. While past reviews provided selective insights, this review aims to collectively compare data from the last decade on (1) plant alkaloid-based anticancer drugs, (2) alkaloid transport across the blood-brain barrier (BBB) in vitro and in vivo, (3) alkaloid mechanisms of action in glioblastoma models (in vitro, in vivo, ex vivo, and in silico), and (4) cytotoxicity and safety profiles. Additionally, innovative drug delivery systems (e.g., nanoparticles and liposomes) are discussed. Focusing on preclinical studies of single plant alkaloids, this review includes 22 botanical families and 28 alkaloids that demonstrated anti-GBM activity. Most alkaloids act in a concentration-dependent manner by (1) reducing glioma cell viability, (2) suppressing proliferation, (3) inhibiting migration and invasion, (4) inducing cell death, (5) downregulating Bcl-2 and key signaling pathways, (6) exhibiting antiangiogenic effects, (7) reducing tumor weight, and (8) improving survival rates. The toxic and adverse effect analysis suggests that alkaloids such as noscapine, lycorine, capsaicin, chelerythrine, caffeine, boldine, and colchicine show favorable therapeutic potential. However, tetrandrine, nitidine, harmine, harmaline, cyclopamine, cocaine, and brucine may pose greater risks than benefits. Piperine's toxicity and berberine's poor bioavailability suggest the need for novel drug formulations. Several alkaloids (kukoamine A, cyclovirobuxine D, α-solanine, oxymatrine, rutaecarpine, and evodiamine) require further pharmacological and toxicological evaluation. Overall, while plant alkaloids show promise in glioblastoma therapy, progress in assessing their BBB penetration remains limited. More comprehensive studies integrating glioma research and advanced drug delivery technologies are needed.

Mental fatigue in golf: A systematic review

Mental fatigue, or cognitive fatigue, is a multi-aspect of exhaustion resulting from prolonged engagement in mentally demanding tasks, characterized by diminished energy, mental exhaustion, and distraction, which can adversely impact various aspects of golfers' performance. However, there are still limited systematic reviews on the interaction between mental fatigue and athletes' performance in golf. This study aims to provide a comprehensive analysis of the correlation between mental fatigue and golf and demonstrate the current state of research and characterization of research in the field. The systematic review was conducted using a PRISMA flow chart, with thorough literature searches across PubMed, Web of Science, SPORTDiscus, Scopus, and China National Knowledge Infrastructure (CNKI) databases. The quality of the literature was assessed using Qualsyst. The study summarized findings from 10 articles on the interaction between mental fatigue and athletes' performance in golf. It indicates that mental fatigue is influenced by factors such as duration of play and walking distance, with prolonged golf tasks inducing mental fatigue. Mental fatigue directly affects golf performance, including the overall score for 18 holes, iron club accuracy, drive distance, and especially impacts putting performance. However, the results of these studies are limited and one-sided because studies conducted on driving ranges or in laboratories focus only on putting performance and ignore other golf skills. The study on the effects of mental fatigue on iron accuracy and driving distance was conducted under competitive conditions on an outdoor golf course, making it impossible to eliminate confounding factors. The lack of intervention studies on other specific golf skills may limit a comprehensive understanding of the impact of mental fatigue on golf performance. Trial registration Systematic Review Registration: [https://inplasy.com/][INPLASY202410111].

Paraxanthine enhances memory and neuroplasticity more than caffeine in rats

Paraxanthine (PXN) is the main metabolite of caffeine (CAF). PXN supplementation has been shown to increase measures of cognition, memory, reasoning, response time, and sustained attention; however, no preclinical study has compared the effects of PXN with those of CAF. The aim of this study was to compare the effects of PXN and CAF on memory and related biomarkers in rats. The effects of two different doses of PXN (PXN LOW, PXN HIGH), CAF (CAF HIGH), and a control group on cognition (escape latency in the Morris water maze test), neurotransmitters (acetylcholine, dopamine, and gamma-aminobutyric acid), and neurochemicals (BDNF, catalase, glutathione, and cyclic GMP) were analyzed from whole brain samples in young (8 weeks old) and aged (16 months old) rats. Compared to the control group, escape latency improved in PXN LOW, PXN HIGH, and CAF HIGH (all P < 0.05) in young animals, and in PXN HIGH and CAF HIGH in older animals (P < 0.001). PXN HIGH improved escape latency compared to CAF HIGH in both young (P < 0.001) and old animals (P = 0.003). BDNF levels increased in PXN LOW, PXN HIGH, and CAF HIGH (all P < 0.001), with PXN HIGH increasing BDNF to a greater extent compared to CAF HIGH (P = 0.03). PXN HIGH also significantly increased BDNF levels compared to PXN LOW (P < 0.001). All other neurotransmitters and neurochemicals significantly increased in the PXN HIGH and CAF HIGH groups compared to the control. In conclusion, PXN showed greater improvements in cognition and BDNF levels compared to CAF, further substantiating PXN as a nootropic with greater benefits compared to CAF.

Assessing the association of coffee consumption on the relationship of chronic pain with depression and anxiety

BACKGROUND

A bidirectional relationship between chronic pain (CP) and mental disorders has been reported, and coffee was believed to be associated with both. However, the association of coffee in this bidirectional relationship remains unclear. We aim to analyze the association of coffee consumption on the relationship of CP with depression and anxiety.

METHODS

A total of 376,813 participants from UK Biobank were included. We collected data on anxiety, depression and CP from objects of our study population. The association of coffee consumption on the relationship of CP with depression and anxiety was assessed through logistic/linear regression models. Moreover, seemingly unrelated estimation test (SUEST) was used to compare whether the coefficients differed in two different groups.

RESULTS

We observed significant associations of coffee consumption in the interaction of CP with depression and anxiety, such as the association of multisite chronic pain (MCP) on self-reported depression (βcoffee = 0.421, βnon-coffee = 0.488, PSUEST = 0.001), and the association of MCP on generalized anxiety disorder-7 (GAD-7) scores (βcoffee = 0.561, βnon-coffee = 0.678, PSUEST = 0.004) were significantly different between coffee drinking and non-coffee drinking groups. Furthermore, in analysis stratified by gender, we found headache (βmale = 0.392, βfemale = 0.214, PSUEST = 0.022) and hip pain (βmale = 0.480, βfemale = 0.191, PSUEST = 0.021) had significant associations with self-reported depression between males and females groups in coffee drinkers.

CONCLUSIONS

Our results suggested that coffee consumption has a significant association on the relationship of CP with depression and anxiety.

Association between self-reported food intake and subjective sleep quality among truck drivers in a city in Southern Brazil

Introduction

Sleep is an activity of great importance for maintaining the homeostasis of the human body and some components may interfere with the quality of sleep, including the pattern of food consumption. Truck drivers may constitute a population particularly sensitive to this association, since they are routinely exposed to situations that may interfere with food intake and sleep quality. Thus, this study investigated the association between self-reported food intake and sleep quality in truck drivers.

Methods

This was a cross-sectional study, with drivers who traveled in a city in southern Brazil. Food intake was evaluated through the average of food intake over the last 30 days. Food intake was evaluated in two forms: division in food groups and evaluation only tryptophan-rich foods. Sleep quality was measured by the Pittsburgh Sleep Quality Index (PSQI). In addition to the descriptive analysis, to identify possible associations between food intake and sleep quality, linear regression, crude and adjusted for confounding variables, were performed to obtain the Beta and Beta adjusted (Betaadj), respectively, and p-value.

Results

A total of 352 truck drivers, mostly males, mean age 48.4 (±11.6) years, with a frequent consumption of meat, fruits, vegetables, sweets, and energy drinks participated in this study. The frequent consumption of dairy products (Betaadj: --0.614. p-value 0.004) and fruits (Betaadj: --0.342. p-value 0.034) was associated with lower PSQI score, while the consumption of energy drinks was associated with a higher PSQI score (Betaadj: 0.923. p-value <0.001). The frequency of consumption of tryptophan-rich foods was not associated with sleep quality.

Conclusion

Fruits and dairy products are associated with better subjective sleep quality, while energy drinks are associated with worse sleep quality in truck drivers, whereas dietary tryptophan-rich foods intake was not associated with sleep quality.

Continuous removal of caffeine in a horizontal-flow anaerobic immobilized biomass bioreactor: identification of transformation products

Anaerobic bioreactors are an efficient technology for the biodegradation of emerging contaminants in environmental matrices. In this work, a horizontal-flow anaerobic immobilized biomass (HAIB) bioreactor was used to remove caffeine (CAF), which is frequently found in various aqueous matrices. The acrylic bench top bioreactor, with dimensions of 100 × 5.00 cm, was operated with a hydraulic retention time (HRT) of 12 h, during 45 weeks, under mesophilic conditions. The operation was performed in 4 phases: without CAF addition (phase I); CAF spiked at 300 μg L-1 (phase II); CAF at 600 μg L-1 (phase III); and CAF at 900 μg L-1 (phase IV). Samples of bioreactor influent and effluent were analyzed by liquid chromatography/tandem mass spectrometry (LC-MS/MS). The bioreactor removed organic matter (OM) and CAF with efficiencies of 88 and 93%, respectively. The first-order apparent removal constant (Kapp) values for OM and CAF were 0.419 and 0.304 h-1, respectively. Five transformation products (TPs) were identified, with m/z 243, 227, 211, and 181 (two products). The HAIB bioreactor is a suitable system for the removal of CAF present in wastewater, even at a concentration level of µg L-1.

Overview of Caffeine Effects on Human Health and Emerging Delivery Strategies

Caffeine is a naturally occurring alkaloid found in various plants. It acts as a stimulant, antioxidant, anti-inflammatory, and even an aid in pain management, and is found in several over-the-counter medications. This naturally derived bioactive compound is the best-known ingredient in coffee and other beverages, such as tea, soft drinks, and energy drinks, and is widely consumed worldwide. Therefore, it is extremely important to research the effects of this substance on the human body. With this in mind, caffeine and its derivatives have been extensively studied to evaluate its ability to prevent diseases and exert anti-aging and neuroprotective effects. This review is intended to provide an overview of caffeine's effects on cancer and cardiovascular, immunological, inflammatory, and neurological diseases, among others. The heavily researched area of caffeine in sports will also be discussed. Finally, recent advances in the development of novel nanocarrier-based formulations, to enhance the bioavailability of caffeine and its beneficial effects will be discussed.

Coffee consumption decreases the connectivity of the posterior Default Mode Network (DMN) at rest

Habitual coffee consumers justify their life choices by arguing that they become more alert and increase motor and cognitive performance and efficiency; however, these subjective impressions still do not have a neurobiological correlation. Using functional connectivity approaches to study resting-state fMRI data in a group of habitual coffee drinkers, we herein show that coffee consumption decreased connectivity of the posterior default mode network (DMN) and between the somatosensory/motor networks and the prefrontal cortex, while the connectivity in nodes of the higher visual and the right executive control network (RECN) is increased after drinking coffee; data also show that caffeine intake only replicated the impact of coffee on the posterior DMN, thus disentangling the neurochemical effects of caffeine from the experience of having a coffee.

Thebromine Targets Adenosine Receptors to Control Hippocampal Neuronal Function and Damage

Theobromine is a caffeine metabolite most abundant in dark chocolate, of which consumption is linked with a lower risk of cognitive decline. However, the mechanisms through which theobromine affects neuronal function remain ill-defined. Using electrophysiological recordings in mouse hippocampal synapses, we now characterized the impact of a realistic concentration of theobromine on synaptic transmission and plasticity. Theobromine (30 μM) facilitated synaptic transmission while decreasing the magnitude of long-term potentiation (LTP), with both effects being blunted by adenosine deaminase (2 U/mL). The pharmacological blockade of A₁R with DPCPX (100 nM) eliminated the theobromine-dependent facilitation of synaptic transmission, whereas the A_2AR antagonist SCH58261 (50 nM), as well as the genetic deletion of A_2AR, abrogated the theobromine-induced impairment of LTP. Furthermore, theobromine prevented LTP deficits and neuronal loss, respectively, in mouse hippocampal slices and neuronal cultures exposed to Aβ_1-42 peptides, considered a culprit of Alzheimer's disease. Overall, these results indicate that theobromine affects information flow via the antagonism of adenosine receptors, normalizing synaptic plasticity and affording neuroprotection in dementia-related conditions in a manner similar to caffeine.

Caffeine consumption attenuates ethanol-induced inflammation through the regulation of adenosinergic receptors in the UChB rats cerebellum

Caffeine consumption is able to interfere in cellular processes related to inflammatory mechanisms by acting through the adenosinergic system. This study aimed to recognize alterations related to adenosinergic system and inflammatory process in the cerebellum of University of Chile Bibulous (UChB) rats after the consumption of ethanol and caffeine. UChB and Wistar rats, males at 5 months old, were divided into the groups (n = 15/group): (i) Control (Wistar rats receiving water); (ii) Ethanol group (UChB rats receiving ethanol solution at 10%) and (iii) Ethanol+caffeine group (UChB rats receiving ethanol solution at 10% added of 3 g/L of caffeine). The cerebellar tissue was collected and processed for immunohistochemistry, Reverse transcription polymerase chain reaction (RT-PCR) and western blotting techniques for the adenosinergic receptors A1 and A2a and inflammatory markers, including Nuclear factor kappa B (NFkB), TLR4, TLR2, MyD88, TNF-α, COX-2, iNOS and microglial marker Iba-1. Results showed ethanol and caffeine consumption differentially altering the immunolocalization of adenosinergic receptors and inflammatory markers in the cerebellar tissue. The A2a receptor was overexpressed in the Ethanol group and was evident in the glial cells. The Ethanol group had increased protein levels for NFκB and TLR4, expressively in Bergmann glia and Purkinje cells. Caffeine reduced the expression of these markers to levels similar to those found in the Control group. The A1 gene was upregulated the Ethanol group, but not its protein levels, suggesting post-transcriptional interference. In conclusion, caffeine seems to attenuate ethanol-induced inflammation in the cerebellum of UChB rats through the A1 and A2a modulation, playing a neuroprotective role in the chronic context of ethanol consumption.

The effect of cocoa-rich products on depression, anxiety, and mood: A systematic review and meta-analysis

In the popular imaginary, cocoa-derived products, like chocolate, represent a panacea for mood and affectivity. However, whether this is a myth or a fact has yet to be clarified. A systematic review and meta-analysis were conducted according to the PRISMA guidelines to investigate the effect of cocoa-derived food on depressive and anxiety symptoms, positive and negative affect. We searched Web of Knowledge^TM and PsycINFO up to April 3, 2020. After screening 761 records, we selected nine studies. Two trials evaluated the long-term effects of cocoa consumption (>1 week), two studies the short-term effects (3 days), while five studies were conducted in acute (single administration). Random-effects meta-analyses found an overall significant effect of cocoa-rich products on depressive (Hedge's g = -0.42, 95% CI -0.67 to -0.17) and anxiety symptoms (Hedge's g = -0.49, 95% CI -0.78 to -0.19). Moreover, both positive (Hedge's g = 0.41, 95% CI 0.06 to 0.77) and negative affect (Hedge's g = -0.47, 95% CI -0.91 to -0.03) significantly improved. In all meta-analyses, the effect size was medium, while heterogeneity was low. Our findings suggest that the consumption of cocoa-rich products may improve affect and mood in the short term. However, given the short duration of trials, our results cannot be generalized to long-term intake of cocoa-derived food. Cautious interpretation is also needed due to the low number of participants and studies included in the meta-analyses.

The Effect of Fermented Porcine Placental Extract on Fatigue-Related Parameters in Healthy Adults: A Double-Blind, Randomized, Placebo-Controlled Trial

Background: Fatigue is one of the major health conditions induced by excessive stress or abnormal immune function or defective antioxidant systems. Placental extract has been reported to have various effects such as immune modulation and cellular regeneration. Fermented porcine placenta (FPP) is a safe nontoxic material, which is highly valuable as a functional food. The aim of this study was to investigate the anti-fatigue effects of FPP supplementation compared with a placebo product. Methods: In this double-blind, parallel, randomized, and placebo-controlled trial 84 healthy males and females, aged between 30 and 60 years were randomized to 320 mg of FPP once daily or placebo. The main outcome measures included efficacy of fatigue-inducing treadmill exercise on physical fatigue and fatigue-related parameters based on the questionnaire administered. Results: The IL-1β mRNA expression and fatigue severity scale were changed significantly after 8 weeks of treatment with fermented porcine placenta compared with placebo (p < 0.05). Cortisol levels were significantly improved in participants younger than 45 years following treatment with FPP compared with placebo. Furthermore, the lactate and myoglobin levels were improved significantly in participants with BMI ≥ 23 kg/m² (p = 0.045 and p = 0.011, respectively) following treatment with FPP versus placebo. Conclusions: Our study showed that FPP supplementation significantly ameliorated fatigue-related parameters and subjective symptoms in healthy adults. Therefore, our results indicate that FPP supplementation induced anti-fatigue effect by regulating the inflammatory response.

Mental energy: plausible neurological mechanisms and emerging research on the effects of natural dietary compounds

Objective: Lack of mental energy is one of the leading reasons adults turn to dietary supplements, with three out of ten supplement users hoping to improve their energy level; even more consume caffeine-containing products for the same reason. Despite this interest from consumers, there is no consensus scientific definition of mental energy or sole validated instrument for measuring it. We performed this review to summarize main findings from research regarding the influence of natural dietary compounds on three aspects of mental energy: cognition (vigilance), motivation (to do mental work), and mood (feelings of energy and/or absence of feelings of fatigue).Methods: A narrative review of key papers.Results: In addition to caffeine, a number of other compounds, including the polyphenols, which are found in all plant-derived products, and the phytochemicals in culinary herbs and herbal products such as Panax ginseng and Ginkgo biloba, have been shown in animal models to modulate neurotransmitter activity potentially relevant to mental energy. Inadequate intake of B vitamins could also potentially have a negative effect on mental energy due to their role in overall energy production, as precursors of key cofactors in the citric acid cycle, as well as their role in brain function and neurotransmitter synthesis. Consumption of some of these products may have direct or indirect effects on one or more elements of mental energy.Conclusion: Large, prospective clinical trials of these products using appropriate, validated instruments designed to measure mental energy may be worthwhile if sufficient evidence exists to justify such trials.

Knowing Your Beans in Parkinson's Disease: A Critical Assessment of Current Knowledge about Different Beans and Their Compounds in the Treatment of Parkinson's Disease and in Animal Models

This review contains a critical appraisal of current knowledge about the use of beans in both animal models and patients with Parkinson's disease (PD). The potential beneficial effects of beans in PD are increasingly being touted, not only in scientific journals but also by the lay media. While there is a long tradition in Ayurvedic medicine of prescribing extracts from Mucuna pruriens (MP), whose seeds contain 5% L-3,4-dihydroxyphenylalanin (L-DOPA), many other beans also contain L-DOPA (broad beans, common beans, and soybeans) or have other ingredients (coffee and cocoa) that may benefit PD patients. Indeed, bean-derived compounds can elicit neuroprotective effects in animal models of PD, while several studies in human PD patients have shown that motor performance can improve after ingestion of bean extracts. However, there are several arguments countering the view that beans serve as a natural therapy for PD: (i) the results from animal PD models are not necessarily directly applicable to humans; (ii) beans have many bioactive ingredients, some of which can be harmful in large doses; (iii) studies in human PD patients are scarce and only report on the effects of single doses or the administration of bean extract over short periods of time; and (iv) no data on long-term efficacy or side effects of bean therapy are available. Therefore, reservations about the use of beans as a "natural" therapy for PD seem to be justified.

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.

Phytochemicals for Improving Aspects of Cognitive Function and Psychological State Potentially Relevant to Sports Performance

Subjective alertness and optimal cognitive function, including in terms of attention, spatial/working memory and executive function, are intrinsic to peak performance in many sports. Consumption of a number of plant-derived 'secondary metabolite' phytochemicals can modulate these psychological parameters, although there is a paucity of evidence collected in a sporting context. The structural groups into which these phytochemicals fall-phenolics, terpenes and alkaloids-vary in terms of the ecological roles they play for the plant, their toxicity and the extent to which they exert direct effects on brain function. The phenolics, including polyphenols, play protective roles in the plant, and represent a natural, benign component of the human diet. Increased consumption has been shown to improve cardiovascular function and is associated with long-term brain health. However, whilst short-term supplementation with polyphenols has been shown to consistently modulate cerebral blood-flow parameters, evidence of direct effects on cognitive function and alertness/arousal is currently comparatively weak. Terpenes play both attractant and deterrent roles in the plant, and typically occur less frequently in the diet. Single doses of volatile monoterpenes derived from edible herbs such as sage (Salvia officinalis/lavandulaefolia) and peppermint (Mentha piperita), diterpene-rich Ginkgo biloba extracts and triterpene-containing extracts from plants such as ginseng (Panax ginseng/quinquefolius) and Bacopa monnieri have all been shown to enhance relevant aspects of cognitive function and alertness. The alkaloids play toxic defensive roles in the plant, including via interference with herbivore brain function. Whilst most alkaloids are inappropriate in a sporting context due to toxicity and legal status, evidence suggests that single doses of nicotine and caffeine may be able to enhance relevant aspects of cognitive function and/or alertness. However, their benefits may be confounded by habituation and withdrawal effects in the longer term. The efficacy of volatile terpenes, triterpene-rich extracts and products combining low doses of caffeine with other phytochemicals deserves more research attention.

Exploring cocoa properties: is theobromine a cognitive modulator?

Nutritional qualities of cocoa have been acknowledged by several authors; a particular focus has been placed on its high content of flavanols, known for their excellent antioxidant properties and subsequent protective effect on cardio- and cerebrovascular systems as well as for neuromodulatory and neuroprotective actions. Other active components of cocoa are methylxanthines (caffeine and theobromine). Whereas the effects of caffeine are extensively researched, the same is not the case for theobromine; this review summarizes evidence on the effect of theobromine on cognitive functions. Considering animal studies, it can be asserted that acute exposition to theobromine has a reduced and delayed nootropic effect with respect to caffeine, whereas both animal and human studies suggested a potential neuroprotective action of long-term assumption of theobromine through a reduction of Aβ amyloid pathology, which is commonly observed in Alzheimer's disease patients' brains. Hence, the conceivable action of theobromine alone and associated with caffeine or other cocoa constituents on cognitive modulation is yet underexplored and future studies are needed to shed light on this promising molecule.

Caffeine: Well-known as psychotropic substance, but little as immunomodulator

To date, numerable reviews are found in the literature prominent to the effect of caffeine on the immune system, with the latest review published in 2006. Database screening reveals around three thousand articles that have been published during the last decade. Interestingly, less than hundred articles involved humans and rodents as tested models, out of which 20% is of interest to this paper excluding studies done on the nervous and cardiac systems, and in pregnant and cancer cases. In this review, information pertaining to the experimental setup of various studies, namely, the tested model, the study type (in vivo or in vitro), and caffeine dose is covered to discern the behaviour of major cellular and molecular immune components in light of caffeine exposure. Although it is hard to extrapolate results done in rodents to humans and to relay conclusions from in vitro to in vivo studies, most of the collected data favor the suppressive effects of caffeine on the proliferation of stimulated lymphocytes. Macrophages and natural killer cells also exhibited a reduced activity in the presence of high caffeine doses compared to increased activity at low doses. Immunosuppression is also supported by reduced levels of major anti-inflammatory cytokines, IL-2, IL-6, TNF-α. Moreover, certain innate and adaptive immune receptors, such as TLR1, TLR2, TLR4, and MHC class I-related chain B (MICB) molecules, exhibited decreased expression levels. Thus, we support the use of caffeine to alleviate various inflammatory conditions and autoimmune diseases.

Acute hematological and mood perception effects of bitter orange extract (p-synephrine) consumed alone and in combination with caffeine: A placebo-controlled, double-blind study

The purpose of this study was to examine acute hematological and mood perception responses to supplementation with p-synephrine alone and in combination with caffeine during quiet sitting. Sixteen subjects visited the laboratory on 6 occasions and were given (in randomized double-blind manner) 103-mg p-synephrine (S), 233-mg caffeine + 104-mg p-synephrine, 240-mg caffeine, 337-mg caffeine + 46-mg p-synephrine, 325-mg caffeine, or a placebo (PL). The subjects sat quietly for 3 hr while completing mood state questionnaires every 30 min. Venous blood samples were collected at baseline (pre) and 3 hr (post) to determine immune, lipid, and chemistry panels. Compared with PL, no significant supplement differences were observed during the S trial with the exception of differential time effects seen in hematocrit (decrease in PL, no change in S), triglycerides and very low-density lipoproteins (no changes in PL, significant decreases in S), and iron (no change in PL, significant elevation in S). Supplements containing caffeine showed increased feelings of attention, excitement, energy, and vigor. These data indicate that consumption of 103-mg p-synephrine does not negatively impact acute blood parameters, does not augment the effects of caffeine, or produce stimulant-like perceptual mood effects.

Scientific Opinion on Flavouring Group Evaluation 49, Revision 1 (FGE.49Rev1): xanthine alkaloids from the priority list

Following a request from the European Commission, the EFSA Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF) was requested to deliver a scientific opinion on the safety assessment of the flavouring substances caffeine [FL-no: 16.016] and theobromine [FL-no: 16.032] in the Flavouring Group Evaluation 49, Revision 1. Consequent to the 2015 scientific opinion from the EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA) on the safety of caffeine from all dietary sources, the CEF Panel considered it inappropriate to evaluate the two substances through the Procedure. For caffeine, the Panel based its assessment on the safety threshold of 5.7 mg/kg body weight (bw) per day for adults, except pregnant/lactating women, and 3 mg/kg bw per day for children, adolescents, pregnant and lactating women, as established by the NDA Panel. The safety evaluation of theobromine takes into account that approximately 11% of an oral dose of caffeine is metabolised to theobromine and that both substances have a similar pharmacological profile. For the exposure assessment, a brand loyalty model was chosen. In this model, it was assumed that a consumer is exposed on a long-term basis to a specific category of food (i.e. non-alcoholic beverages), containing caffeine or theobromine at their respective maximum use levels. For the rest of the categories, normal use levels applied. Daily dietary exposure to caffeine and theobromine (excluding systemic exposure) added as a chemically defined flavouring substance ranged 0-2.3 and 0-0.4 mg/kg bw, respectively, across all population groups. The Panel concluded that caffeine [FL-no: 16.016] and theobromine [FL-no: 16.032] would not be expected to present safety concern based on their estimated levels of intake from their use as flavouring substances.

Theobromine up-regulates cerebral brain-derived neurotrophic factor and facilitates motor learning in mice

Theobromine, which is a caffeine derivative, is the primary methylxanthine produced by Theobroma cacao. Theobromine works as a phosphodiesterase (PDE) inhibitor to increase intracellular cyclic adenosine monophosphate (cAMP). cAMP activates the cAMP-response element-binding protein (CREB), which is involved in a large variety of brain processes, including the induction of the brain-derived neurotrophic factor (BDNF). BDNF supports cell survival and neuronal functions, including learning and memory. Thus, cAMP/CREB/BDNF pathways play an important role in learning and memory. Here, we investigated whether orally administered theobromine could act as a PDE inhibitor centrally and affect cAMP/CREB/BDNF pathways and learning behavior in mice. The mice were divided into two groups. The control group (CN) was fed a normal diet, whereas the theobromine group (TB) was fed a diet supplemented with 0.05% theobromine for 30 days. We measured the levels of theobromine, phosphorylated vasodilator-stimulated phosphoprotein (p-VASP), phosphorylated CREB (p-CREB), and BDNF in the brain. p-VASP was used as an index of cAMP increases. Moreover, we analyzed the performance of the mice on a three-lever motor learning task. Theobromine was detectable in the brains of TB mice. The brain levels of p-VASP, p-CREB, and BDNF were higher in the TB mice compared with those in the CN mice. In addition, the TB mice performed better on the three-lever task than the CN mice did. These results strongly suggested that orally administered theobromine acted as a PDE inhibitor in the brain, and it augmented the cAMP/CREB/BDNF pathways and motor learning in mice.

Does Caffeine Consumption Modify Cerebrospinal Fluid Amyloid-β Levels in Patients with Alzheimer's Disease?

Caffeine may be protective against Alzheimer's disease (AD) by modulating amyloid-β (Aβ) metabolic pathways. The present work aimed to study a possible association of caffeine consumption with the cerebrospinal fluid (CSF) biomarkers, particularly Aβ. The study included 88 patients with AD or mild cognitive impairment. The consumption of caffeine and theobromine was evaluated using a validated food questionnaire. Quantification of caffeine and main active metabolites was performed with liquid chromatography coupled to tandem mass spectrometry. The levels of A(1-42), total tau, and phosphorylated tau in the CSF were determined using sandwich ELISA methods and other Aβ species, Aβ(X-38), Aβ(X-40), and Aβ(X-42), with the MSD Aβ Triplex assay. The concentration of caffeine was 0.79±1.15 μg/mL in the CSF and 1.20±1.88 μg/mL in the plasma. No correlation was found between caffeine consumption and Aβ42 in the CSF. However, a significant positive correlation was found between the concentrations of theobromine, both in the CSF and in the plasma, with Aβ42 in the CSF. Theobromine in the CSF was positively correlated with the levels of other xanthines in the CSF, but not in the plasma, suggesting that it may be formed by central metabolic pathways. In conclusion, caffeine consumption does not modify the levels of CSF biomarkers, and does not require to be controlled for when measuring CSF biomarkers in a clinical setting. Since theobromine is associated with a favorable Aβ profile in the CSF, the possibility that it might have a protective role in AD should be further investigated.

A method to predict different mechanisms for blood-brain barrier permeability of CNS activity compounds in Chinese herbs using support vector machine

The blood-brain barrier (BBB), a highly selective barrier between central nervous system (CNS) and the blood stream, restricts and regulates the penetration of compounds from the blood into the brain. Drugs that affect the CNS interact with the BBB prior to their target site, so the prediction research on BBB permeability is a fundamental and significant research direction in neuropharmacology. In this study, we combed through the available data and then with the help of support vector machine (SVM), we established an experiment process for discovering potential CNS compounds and investigating the mechanisms of BBB permeability of them to advance the research in this field four types of prediction models, referring to CNS activity, BBB permeability, passive diffusion and efflux transport, were obtained in the experiment process. The first two models were used to discover compounds which may have CNS activity and also cross the BBB at the same time; the latter two were used to elucidate the mechanism of BBB permeability of those compounds. Three optimization parameter methods, Grid Search, Genetic Algorithm (GA), and Particle Swarm Optimization (PSO), were used to optimize the SVM models. Then, four optimal models were selected with excellent evaluation indexes (the accuracy, sensitivity and specificity of each model were all above 85%). Furthermore, discrimination models were utilized to study the BBB properties of the known CNS activity compounds in Chinese herbs and this may guide the CNS drug development. With the relatively systematic and quick approach, the application rationality of traditional Chinese medicines for treating nervous system disease in the clinical practice will be improved.

Acute effects of dietary constituents on motor skill and cognitive performance in athletes

Performance in many sports is at least partially dependent on motor control, coordination, decision-making, and other cognitive tasks. This review summarizes available evidence about the ingestion of selected nutrients or isolated compounds (dietary constituents) and potential acute effects on motor skill and/or cognitive performance in athletes. Dietary constituents discussed include branched-chain amino acids, caffeine, carbohydrate, cocoa flavanols, Gingko biloba, ginseng, guarana, Rhodiola rosea, sage, L-theanine, theobromine, and tyrosine. Although this is not an exhaustive list, these are perhaps the most researched dietary constituents. Caffeine and carbohydrate have the greatest number of published reports supporting their ability to enhance acute motor skill and cognitive performance in athletes. At this time, there is insufficient published evidence to substantiate the use of any other dietary constituents to benefit sports-related motor skill or cognitive performance. The optimal dose and timing of caffeine and carbohydrate intake promoting enhanced motor skill and cognitive performance remain to be identified. Valid, reliable, and sensitive batteries of motor skills and cognitive tests should be developed for use in future efficacy studies.

Cocoa bioactive compounds: significance and potential for the maintenance of skin health

Cocoa has a rich history in human use. Skin is prone to the development of several diseases, and the mechanisms in the pathogenesis of aged skin are still poorly understood. However, a growing body of evidence from clinical and bench research has begun to provide scientific validation for the use of cocoa-derived phytochemicals as an effective approach for skin protection. Although the specific molecular and cellular mechanisms of the beneficial actions of cocoa phytochemicals remain to be elucidated, this review will provide an overview of the current literature emphasizing potential cytoprotective pathways modulated by cocoa and its polyphenolic components. Moreover, we will summarize in vivo studies showing that bioactive compounds of cocoa may have a positive impact on skin health.