ArticleLiterature Review

Effect of Green Tea Phytochemicals on Mood and Cognition

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Abstract

Background: Green tea is traditionally known to induce mental clarity, cognitive function, physical activation and relaxation. Recently, a special green tea, matcha tea, is rapidly gaining popularity throughout the world and is frequently referred to as a mood- and brain food. Matcha tea consumption leads to much higher intake of green tea phytochemicals compared to regular green tea. Previous research on tea constituents caffeine, L-theanine, and epigallocatechin gallate (EGCG) repeatedly demonstrated benefits on mood and cognitive performance. These effects were observed when these phytochemicals were consumed separately and in combination. Methods: A review was conducted on 49 human intervention studies to summarize the research on acute psychoactive effects of caffeine, L-theanine, and EGCG on different dimensions of mood and cognitive performance. Conclusions: Caffeine was found to mainly improve performance on demanding long-duration cognitive tasks and self-reported alertness, arousal, and vigor. Significant effects already occurred at low doses of 40 mg. L-theanine alone improved self-reported relaxation, tension, and calmness starting at 200 mg. L-theanine and caffeine combined were found to particularly improve performance in attention-switching tasks and alertness, but to a lesser extent than caffeine alone. No conclusive evidence relating to effects induced by EGCG could be given since the amount of intervention studies was limited. These studies provided reliable evidence showing that L-theanine and caffeine have clear beneficial effects on sustained attention, memory, and suppression of distraction. Moreover, L-theanine was found to lead to relaxation by reducing caffeine induced arousal.

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... A 2017 review of 49 human intervention studies evaluating research on the psychoactive effects of L-theanine, caffeine and EGCG found that L-theanine and caffeine have clear beneficial effects on sustained attention, memory, and suppression of distraction. Moreover, L-theanine was found to lead to relaxation by reducing caffeine induced arousal [15]. Caffeine significantly increases the risk of chronic diseases such as type 2 diabetes mellitus, cardiovascular disease and certain cancers. ...
... Whilst green tea is frequently highlighted for its health benefits, there is a large body of evidence for black tea with studies appearing to indicate that drinking 3-4 cups of black tea daily could help to maintain health and wellness throughout life. The flavonoids present in both black and green tea are considered to be key contributors to these health benefits, although evidence shows that the amino-acid L-theanine may also make an important contribution [15]. ...
... Whilst caffeine has been thought to be the main contributor to the mood improvement effects of tea, our findings indicate that L-theanine, an amino acid present in black tea and green tea, with recent evidence showing that it is found in black tea in greater concentrations, may be a key bioactive responsible for mood and mental health improvement. This review also shows the potential benefits of L-theanine on memory and alertness with an ability to act in concert with caffeine but to dampen the stimulant spike of caffeine and induce relaxation [15]. Tea has also been shown to have an antidepressant action with meta-analysis indicating a 37% reduction in depression in people drinking three cups of tea daily [20]. ...
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Tea (Camellia sinensis) is the most commonly consumed beverage globally after water, with black tea being the most popular type of tea drunk in Britain by people of all ages. The potential for tea to contribute to health and wellness throughout life is worthy of consideration. Tea is a low calorie drink with several bioactive polyphenol ingredients which are well known to have antioxidant activity. Black tea in particular is a source of the amino acid L-theanine which has been linked with benefits for mental, immune and cardiovascular health. Prevalence of poor health, including poor cardiovascular, metabolic, mental, brain, bone and immune health, which may result in serious outcomes, including heart disease, type 2 diabetes, osteoporosis, cognitive decline and an inability to fight infection, is high in the UK and the European region. Interest in safe, natural ingredients for promoting health and wellness is growing. Whilst tea has been consumed for centuries, its health benefits have emerged more powerfully during recent decades giving scientific credence to the traditional perception that tea makes those who include it in their pattern of daily life feel good. This review collates evidence from human studies which evaluate the health and wellness impacts of tea consumption throughout life including into old age. It explores the evidence available on tea and mental and cognitive health, cardiovascular health, metabolic health, bone health, gut health and immune health. It identifies the bioactive ingredients which are likely contributors to these health impacts and includes evidence from laboratory studies that help to explain the mechanisms by which these benefits may occur. Overall, this review concludes that tea consumption contributes to health and wellness throughout life and that everyone should be encouraged to enjoy three cups daily as part of a healthy lifestyle pattern.
... Its role in anxiety and stress relief and improving sleep quality is commonly known [42,43], and it has been suggested to possess the ability to prevent stress-induced brain atrophy by modifying early stress responses [44]. Caffeine, which is abundant in tea, strengthens the effect of theanine on the enhancement of neurophysiological performance, such as attention [45]. As for fat-soluble nutrients, the role of vitamin K and lutein has been well noted. ...
... Furthermore, L-theanine and caffeine are known to improve cognitive performance, either by increasing the dopaminergic and cholinergic transmission in the brain, or through glutamatergic mechanisms. The previous study showed that the combination of these compounds caused significant improvement in cognitive performance, possibly due to the modulation of neuronal activities in the brain [45]. It has also been suggested that if taken together these compounds have additive effects on improving attention span [83]. ...
... In this study, the amount of matcha powder consumed per day was 3 g. In previous clinical trials investigating the non-acute effects of green tea powder on cognitive function, consumption was similar to that in this study (2 g/day [91]; 4 g/day [45]). The drinks in the active group contained 81 mg of caffeine per day. ...
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Matcha Green Tea Powder contains a variety of active ingredients beneficial to health, such as tea catechins, lutein and vitamin K. It is also known that these ingredients confer benefits upon cognitive functions of elderly people. Therefore, we aimed to investigate the relationship between a daily supplementation of Matcha and the change in cognitive functions of community-dwelling elderly people. A randomized, double-blind, placebo-controlled 12-week trial was performed. Sixty-one participants were recruited and randomly assigned to receive test drink containing 3 g powder from fresh Matcha or placebo powder per day. Changes in cognitive function were assessed utilizing a psychometric test battery. Daily food intake was assessed by a Brief-type Self-administered Diet History Questionnaire (BDHQ). In the gender-specific analysis, a significant cognitive enhancement was observed in the Montreal Cognitive Assessment (MoCA) score in the active group of women. In dietary analysis, we found a significant inverse correlation between consumption of vitamin K in daily diet, excluding test drinks, and change in MoCA. The present study suggests that daily supplementation of Matcha Green Tea Powder has protective effects against cognitive decline in community-dwelling elderly women.
... Dietz & Dekker [29] L-theanine and caffeine may be reduce deviation of attention to distractors (i.e. mind wandering) subsequently enhancing attention. ...
... The amino acid L-theanine and caffeine are also thought to have potential synergistic actions -they are anticipated to reduce mind-wandering and improve attention to targeted stimuli [28,29]. In one systematic review [30] 200-400 mg/ day of L-theanine was thought to be a potential means of reducing stress and anxiety in people exposed to stressful conditions. ...
... In a more realistic study -50 mg L-theanine (equivalent to 2-3 cups of tea) increased alpha brain wave activity, indicating that it improved attention and mental arousal [31]. In other work L-theanine reinforced relaxation by attenuating caffeine-induced stimulation [29]. ...
... Whilst caffeine has mainly been associated with increased wakefulness, L-theanine appeared to have opposite effects, increasing relaxation and calmness at doses of 200 mg. 44 L-theanine appears to exert its most beneficial effect in combination with caffeine. For instance, the consumption of L-theanine and caffeine resulted in an improved attentional switching (AS) task performance than with caffeine alone, 44 Although another study by Giles et al. found that caffeine and L-theanine exert opposite effects ...
... 44 L-theanine appears to exert its most beneficial effect in combination with caffeine. For instance, the consumption of L-theanine and caffeine resulted in an improved attentional switching (AS) task performance than with caffeine alone, 44 Although another study by Giles et al. found that caffeine and L-theanine exert opposite effects ...
Article
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.
... Recently, several lines of evidence focus on the positive effects of a single dose caffeine drink (30-50 mg caffeine) which is equal to a cup of instant coffee, a cup of tea, a 375 ml can of Coke@, a 375 ml can of Red Bull@ as a central nervous system stimulant [9,14,21]. A literature review by Glade [14] reported that a single dose of 32 to 50 mg of caffeine could improve alertness and concentration 20 min after consumption. ...
... A literature review by Glade [14] reported that a single dose of 32 to 50 mg of caffeine could improve alertness and concentration 20 min after consumption. Furthermore, the study by Dietz & Dekker [9] indicated that 40 mg of caffeine is sufficient to affect attention levels. Lieberman et al. [21] reported that drinking 32 mg of caffeine could improve auditory vigilance and visual reaction time. ...
Article
The effects of a low dose of caffeine, administered in the morning, on brain wave activity and cognitive function were investigated in 25 healthy university Southeast Asian men (mean age ±standard deviation: 21 ± 2 years). Participants received a placebo (PLA) or a 50 mg caffeinated drink (CAF) under randomized, double-blind crossover conditions, with 1 week between conditions. Brain wave activity was assessed using electroencephalography (EEG) from a 5 min eyes-closed resting state. Cognitive function, i.e., visuomotor processing speed, working memory, and attention were assessed using the trail-making test A (Trails A) and B (Trails B), and digit span Forwards (DF), respectively. All tests were examined before drinking (BD), 30 min after drinking (AD), and 35 min after 5-min isokinetic exercise (AE). [Results] The CAF showed a significant decrease in the percentage changes from baseline (%∆) of alpha wave activity over the midline electrodes, i.e., frontal, central, and occipital areas after AD (p<0.05). Data from cognitive function tests were significantly improved after AD (p<0.05). A significant inverse correlation between the diminished alpha wave activity over the midline central and occipital cortical regions and the Trails B positive scores were observed (p<0.05). [Conclusion] The diminishment in resting alpha wave activity and improvement of cognitive function on working memory assessed by the Trails B following caffeine consumption would support the stimulant effects of low-dose caffeine as a morning wake-up drink in young adults.
... Green tea is also notable for vitamins such as vitamin A, E, and B complex (Fernández et al., 2002), minerals, and trace elements such as K, Mn, Cr, Zn, and Ni (Komes et al., 2010). Alkaloids such as L-Theanine, catechin epigallocatechin gallate, proanthocyanidins, and flavonols such as myricetin, kaempferol, and coumarin, among others, contribute to green tea's beneficial properties (Dietz and Dekker, 2017). The composition of bioactive molecules in tea depends on the age of the leaf, harvesting time, climate of production, and processing method. ...
... Most of the components of green tea can cross the blood-brain barrier. The bioavailability of the components depends on molecular weight, the number of hydroxyl groups, and conjugation (Dietz and Dekker, 2017). ...
Article
Recent scientific advancements have sparked an increasing trend of returning to nature. Scientists worldwide prefer natural medical derivatives over synthetic ones due to fewer side effects. Green tea is abundant in bioactive components and vitamins. Although most components of green tea were thought to be absorbed inadequately by oral administration, they are essential for better health. In the present study, an in silico approach was taken to evaluate the effect or correlation of bioactive components of tea on memory retention, cognitive performance, and prevention of neurodegenerative diseases that result in memory alterations, dementia, and cognitive dysfunction. Furthermore, binding of bioactive components with brain-specific proteins and possible alterations in those proteins due to tea components were illustrated. Four critical brain-specific proteins were evaluated in the present molecular analysis. Cyclooxygenase 1 (COX1), Acetylcholinesterase (AChE), Amyloid-β Precursor Protein (APP1), and Cytochrome P4502D6 (Cyp2D6) were the proteins involved. Their interaction with the bioactive components of green tea was evaluated using computational molecular docking analysis (CMDA). The bioactive molecules were Epigallocatechin gallate (EGCG), L-Theanine, Kaemferol, Coumarin, and Myricetin. The beneficial effect of green tea on memory was prioritized in this study. CMDA has shown possible inhibition of acetylcholinesterase, amyloid-β protein, cyclooxygenase 1, and Cytochrome P4502D6 (Cyp2D6). Bioactive components of green tea passed the blood-brain barrier and influenced short-term memory at low concentrations. Significant dosage or concentration in capsulated form might result in long-term effects since both bioavailability, and concentration of essential components of green tea are scarce. Bioresearch Commu. 8(2): 1113-1123, 2022 (July)
... Since tea is important to human life, a vast number of researches have investigated the function of tea. It has been found that tea has beneficial effects on both physical health (Ruxton, Phillips, & Bond, 2015;Shen & Chyu, 2016;Hayat, Iqbal, Malik, Bilal, & Mushtaq, 2015) and cognition (Einöther & Martens, 2013;Dietz & Dekker, 2017;Kuriyama et al., 2006). Recent research for tea's effect on cognition is examining the relationship between drinking tea and creativity (Einöther, Baas, Rowson, & Giesbrecht, 2015). ...
... The essence of meditation is relaxation, and the essence of open-monitoring meditation is "open", "accepting myself as I am", which is much similar to tea's recovery effect from stress (Steptoe et al., 2007). Therefore, one would expect that tea would promote divergent creativity because of its function of promoting relaxation (Dietz & Dekker, 2017) just as meditation does. ...
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Previous research has found that tea improves performance on convergent creativity tasks, such as the Remote Associates Test, by inducing a positive mood. However, there is no empirical evidence regarding the effect of tea drinking on performance in divergent creativity tasks. Using two experiments, the current research investigates the relationship between tea consumption and divergent creativity. In both experiments, participants were randomly assigned to two groups and implicitly manipulated to drink tea or water. In experiment 1 (N = 50), we used a block-building task as a measure of divergent creativity in spatial cognition. The results showed that the participants who drank tea performed better in the spatial creativity task assigned in the 10 min immediately following tea consumption than did those who drank water. In experiment 2 (N = 40), we adopted the restaurant naming task as a measure of divergent creativity in semantic cognition. The results showed that the participants who drank tea received higher scores in the semantic creativity task compared to those who drank water. The current research demonstrates that drinking tea can improve creative performance with divergent thinking. This work contributes to understanding the function of tea on creativity and offers a new way to investigate the relationship between food and beverage consumption and the improvement of human cognition.
... Since tea is important to human life, a vast number of researchers have investigated the function of tea. It has been found that tea has beneficial effect on both physical health and cognition [5][6][7]. All tea is produced from the leaves of Camellia sinensis, but differences in processing result in different types of tea. ...
... There is a recognized association between cognition and emotion that may explain the improved psychological state of medical staff who had a scientific understanding of the epidemic [17,18]. Their medical training and daily work require them to be calm and objective when faced with emergencies, which may result in a more objective way of thinking and a controlled way of behaving during crises, such as an epidemic [19,20]. ...
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BACKGROUND During February 2020, the coronavirus disease 2019 (COVID-19) epidemic in Hubei Province, China, was at its height, requiring isolation of the population. This study aimed to compare the emotional state, somatic responses, sleep quality, and behavior of people in Hubei Province with non-endemic provinces in China during two weeks in February 2020. MATERIAL AND METHODS Questionnaires were completed by 939 individuals (357 men; 582 women), including 33 from Hubei and 906 from non-endemic provinces. The Stress Response Questionnaire (SRQ) determined the emotional state, somatic responses, and behavior. The Pittsburgh Sleep Quality Index (PSQI) was used to measure the duration of sleep and sleep quality. RESULTS There were 939 study participants, aged 18-24 years (35.89%) and 25-39 years (35.57%); 65.92% were university students. During a two week period in February 2020, the emotional state and behavior of participants in Hubei improved, but the quality of sleep did not. Health workers and business people became increasingly anxious, but other professionals became less anxious. The data showed that most people in Hubei Province developed a more positive attitude regarding their risk of infection and the chances of surviving the COVID-19 epidemic. CONCLUSIONS During a two-week period, front-line health workers and people in Hubei Province became less anxious about the COVID-19 epidemic, but sleep quality did not improve. Despite public awareness, levels of anxiety exist that affect the quality of life during epidemics, including periods of population quarantine. Therefore, health education should be combined with psychological counseling for vulnerable individuals.
... Global tea consumption in 2018 was estimated at 273 billion liters per annum and projected to increase to 297 billion liters by 2021 (three times as much as coffee consumption rates) (1). The Tea Association of the US estimate that some 159 million Americans consume tea on a daily basis (2) partly due to the beverage satisfaction, as well as perceived health benefits (3)(4)(5). All tea comes from the leaves/buds of the Camellia sinensis plant, and based on fermentation processing results in the main black, white, oolong, green, yellow and pu-erh tea classifications. ...
Article
Objective: This study aimed to investigate the potential antiobesity benefits of hot tea consumption at the population level. Methods: Using data from the National Health and Nutrition Examination Survey (NHANES) 2003-2006, the association between hot tea consumption and dual-energy x-ray-measured body fat was examined in a large representative sample of US adults (n = 5,681, 51.9% women). Results: Compared with non-tea drinkers, men who consumed 0.25 to 1 cup per day of hot tea had 1.5% (95% CI: 0.4% to 2.6%) and 1.7% (95% CI: 0.4% to 3.0%) less total and trunk body fat, respectively. The associations were stronger among men 45 to 69 years old compared with younger men (20-44 years). For men who consumed 1 or more cups per day of hot tea, lower total (-1.2%, 95% CI: -2.3% to -0.2%) and trunk body fat (-1.3%, 95% CI: -2.6 to -0.1%) was observed among men 45 to 69 years old only. In women, those who drank 1 or more cups per day had 1.5% lower (95% CI: -2.7% to -0.3%) trunk body fat compared with non-tea drinkers. Conclusions: Consumption of hot tea might be considered as part of a healthy diet in order to support parameters associated with metabolic health and may be particularly important in older male age groups in supporting reduced central adiposity.
... Catechins (0.53%), EGCG (11.16%) and Epicatechin (2.45%) [16]. It's been estimated that in one cup of green tea the expected concentration of EGCG is between 2.1-2.4 mg/mL and after testing the effects of both Green tea and EGCG (equivalent of 4-8 cups per day) on human subjects there was no appreciable side effects observed [17,18] ...
... Although caffeine has been primarily associated with increased alertness, L-theanine appears to have the opposite effects, increasing relaxation and calm, but L-Complimentary Copy theanine appears to exert its most beneficial effect in combination with caffeine. For example, consumption of L-theanine and caffeine resulted in a better attention shifting effect compared to just caffeine (Dietz and Dekker 2017). Although most beneficial effects should be attributed to caffeine and its dose, the antagonism of L-theanine can reduce unpleasant side effects such as the jittery sensation of caffeine. ...
Chapter
Caffeine (1,3,7 trimethylxanthine) is the most psychoactive substance consumed worldwide. Caffeine is so hegemonic in modern society that it can be used as an anthropogenic marker of drinking water quality (contamination by the sewage system), due to its excretion by urine and massive consumption in urban centers. Caffeine affects the central nervous system, the cardiac muscle, the respiratory system, and the secretion of gastric acid. It has no nutritional value, but its antioxidant activity is proven to be relevant to some free radicals. Common sense or conflicting data such as the association of caffeine intake with neurodegenerative diseases like Parkinson’s and Alzheimer’s, teratogenic effects, and even autoimmune diseases will be discussed in terms of natural drinks, where synergistic effects with other substances must be considered. In this chapter, we also discuss the levels of caffeine in different types of beverages: coffee, mate, tea, chocolate, and energy drinks with their effects on the cardiovascular system, besides caffeine levels in coffee on different roasting degrees. The concept of slow�release caffeine, the efforts to remove it from coffee with specific extraction methods, coffee surrogate foods, stomach-friendly coffees, and its cosmetic uses will be explored as well.
... While the confidence intervals in our study include the null, the point estimates are similar to results of other outcomes. These findings may be due to mental or psychological factors as drinking green tea may have a calming effect while simultaneously improving alertness [59]. The possibility of residual confounding unadjusted for in this analysis cannot be excluded. ...
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The aim of our study was to assess the association between green tea consumption and all-cause and cause-specific mortality in a pooled analysis of eight Japanese population-based cohort studies. Pooled hazard ratios (HR) and 95% confidence intervals (CI), derived from random effects models, were used to evaluate the associations between green tea consumption, based on self-report at baseline, and risk of all-cause and cause-specific mortality. During a mean follow-up of 17.3 years, among 313,381 persons, 52,943 deaths occurred. Compared with individuals who consumed < 1 cup/day, those in the highest consumption category (≥ 5 cups/day) had a decreased risk of all-cause mortality [the multivariate-adjusted HR was 0.90 (95% CI 0.87–0.94) for men and 0.82 (0.74–0.90) for women]. A similar inverse association was observed for heart disease mortality [HR 0.82 (0.75–0.90) for men, and 0.75 (0.68–0.84) for women], and cerebrovascular disease mortality [HR 0.76 (0.68–0.85) for men, and 0.78 (0.68–0.89) for women]. Among women, green tea consumption was associated with decreased risk of total cancer mortality: 0.89 (0.83–0.96) for the 1–2 cups/day category and 0.91 (0.85–0.98) for the 3–4 cups/day category. Results for respiratory disease mortality were [HR 0.75 (0.61–0.94)] among 3–4 cup daily consumers and [HR 0.66 (0.55–0.79)] for ≥ 5 cups/day. Higher consumption of green tea is associated with lower risk for all-cause mortality in Japanese, especially for heart and cerebrovascular disease. Moderate consumption decreased the risk of total cancer and respiratory disease mortality in women.
... Tea contains bioactive flavonoids, and therefore has received much attention due to it's beneficial health attributes. Tea has been found to have beneficial effects on both physical health [1][2][3] and cognition [4,5]. Flavonoids, including anthocyanidins, flavan-3-ols, flavonols, flavones, flavanones and isoflavones, are important water-soluble pigments, which are plant secondary metabolites [6]. ...
Article
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Almost all flowers of the tea plant (Camellia sinensis) are white, which has caused few researchers to pay attention to anthocyanin accumulation and color changing in tea flowers. A new purple-leaf cultivar, Baitang purple tea (BTP) was discovered in the Baitang Mountains of Guangdong, whose flowers are naturally pink, and can provide an opportunity to understand anthocyanin metabolic networks and flower color development in tea flowers. In the present study, twelve anthocyanin components were identified in the pink tea flowers, namely cyanidin O-syringic acid, petunidin 3-O-glucoside, pelargonidin 3-O-beta-d-glucoside, which marks the first time these compounds have been found in the tea flowers. The presence of these anthocyanins seem most likely to be the reason for the pink coloration of the flowers. Twenty-one differentially expressed genes (DEGs) involved in anthocyanin pathway were identified using KEGG pathway functional enrichment, and ten of these DEG’s screened using venn and KEGG functional enrichment analysis during five subsequent stages of flower development. By comparing DEGs and their expression levels across multiple flower development stages, we found that anthocyanin biosynthesis and accumulation in BTP flowers mainly occurred between the third and fourth stages (BTP3 to BTP4). Particularly, during the period of peak anthocyanin synthesis 17 structural genes were upregulated, and four structural genes were downregulated only. Ultimately, eight critical genes were identified using weighted gene co-expression network analysis (WGCNA), which were found to have direct impact on biosynthesis and accumulation of three flavonoid compounds, namely cyanidin 3-O-glucoside, petunidin 3-O-glucoside and epicatechin gallate. These results provide useful information about the molecular mechanisms of coloration in rare pink tea flower of anthocyanin-rich tea, enriching the gene resource and guiding further research on anthocyanin accumulation in purple tea.
... Depending on the neurotransmitter system, caffeine can affect different brain areas with different functions (Meeusen et al., 2013). Usually, caffeine has delayed effect about 3-4 h of half-life (Knutti et al., 1981(Knutti et al., , 1982Nehlig, 2016), caffeine's behavioral effects and the significant increase in psychomotor performance it causes have been documented in a large body of literature, in addition to improvements in attention- (Temido-Ferreira et al., 2019;Alasmari, 2020;Franceschini et al., 2020;Irwin et al., 2020;Jahrami et al., 2020), mood-, and vigor-based tasks (Dietz and Dekker, 2017;Shabir et al., 2018;Alasmari, 2020). Moreover, Beaumont et al. (2005) found that the action of caffeine both shortened response times and reduced the number of errors on psychomotor tests, which indicates that caffeine has a global action on information processing and divided attention management (Beaumont et al., 2005;Wilhelmus et al., 2017). ...
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Objective: Caffeine is a central nervous system stimulant that can effectively alleviate brain fatigue and low cognitive efficiency induced by total sleep deprivation (TSD). Recent studies have demonstrated that caffeine can improve subjective attention and objective behavioral metrics, such as arousal level, reaction time, and memory efficiency. However, only a few studies have examined the electrophysiological changes caused by the caffeine in humans following sleep disturbance. In this study, an event-related potential (ERP) technique was employed to measure the behavioral, cognitive, and electrophysiological changes produced by caffeine administration after TSD.Methods: Sixteen healthy subjects within-subject design performed a visual Go/No-Go task with simultaneous electroencephalogram recording. Behavioral and ERP data were evaluated after 36 h of TSD, and the effects of ingestion of either 400 mg of caffeine or placebo were compared in a double-blind randomized design.Results: Compared with placebo administration, the Go hit rates were significantly enhanced in the caffeine condition. A simple effect analysis revealed that, compared with baseline, the Go-P2 amplitude was significantly enhanced after TSD in the caffeine consumption condition. A significant main effect of the drug was found on No-Go-P2, No-Go-N2 amplitude, and Go-P2 latency before and after TSD.Conclusion: Our findings indicate that caffeine administration has acute effects on improving the efficiency of individual automatic reactions and early cognitive processes. Caffeine was related to the preservation of an individual’s arousal level and accelerated response-related decisions, while subjects’ higher-level recognition had limited improvement with prolonged awareness.
... In contrast to our study, other cohort studies in elderly Asian adults reported less cognitive decline with higher green tea intake [21,86] rich in antioxidant, anti-inflammatory, and neuroprotective phytochemicals such as flavonoids, catechins [87][88][89], and caffeine [71,72]. In our study higher green tea intake were not significantly associated with incident AD or memory decline. ...
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Background: Evidence whether single “cognitive health” foods could prevent cognitive decline is limited. We investigated whether dietary intake of red wine, white wine, coffee, green tea, olive oil, fresh fish, fruits and vegetables, red meat and sausages, assessed by a single-food-questionnaire, would be associated with either incident Alzheimer’s dementia (AD) or verbal memory decline. Methods: Participants aged 75+ of the German Study on Aging, Cognition and Dementia in Primary Care Patients (AgeCoDe) cohort were regularly followed over 10 years (n = 2622; n = 418 incident AD cases). Multivariable-adjusted joint modeling of repeated-measures and survival analysis was used, taking gender and Apolipoprotein E4 (APOE ε4) genotype into account as possible effect modifiers. Results: Only higher red wine intake was associated with a lower incidence of AD (HR = 0.92; P = 0.045). Interestingly, this was true only for men (HR = 0.82; P < 0.001), while in women higher red wine intake was associated with a higher incidence of AD (HR = 1.15; P = 0.044), and higher white wine intake with a more pronounced memory decline over time (HR = −0.13; P = 0.052). Conclusion: We found no evidence for these single foods to be protective against cognitive decline, with the exception of red wine, which reduced the risk for AD only in men. Women could be more susceptible to detrimental effects of alcohol.
... Changes in brain alpha oscillatory activity have been electroencephalographic monitored as correlates of l-theanine potential anti-stress effects by the use of recordings obtained in resting state, and cognitive enhancing effects by the use of task-related recordings [71]. The positive effects of l-theanine in humans seems however to be magnified when it is associated to caffeine [72]. In fact, caffeine can block all four subtypes of adenosine receptors (A1, A2A, A2B, and A3) with most off its actions mediated by high affinityA1 andA2Areceptor.The antagonist effect of caffeine on adenosine receptors may induce upregulation of those receptors and improve the function of blood-brain barrier and, by this mechanism, protect against AD [73]. ...
Article
Beyond the well-known effects on cognitive impairment of the Mediterranean diet, a number of studies have investigated the possible action on cognitive decline of different botanicals and phytochemicals, most of which are well-known anti-inflammatory or antioxidant agents with a good tolerability and safety profile. In particular, the current literature supports the use of Ginkgo biloba, resveratrol, epigallocatechin-3-gallate and l-theanine, Theobroma cacao, Bacopa monnieri, Crocus sativus and curcumin, which might have a positive impact on cognitive impairment used alone or in combination with other nutraceuticals or traditional drugs. Then, the aim of the present study was to review and comment the available evidence on botanicals and phytochemicals with a clinically demonstrable effect on cognitive decline. For this reason, we carefully reviewed studies published in English language from 1970 to April 2017 on botanicals and phytochemical claiming to show an effect on cognitive impairment in humans. Thus, the terms 'botanicals', 'dietary supplements', 'herbal drug', 'nutraceuticals', 'phytochemical', 'cognitive impairment', 'Alzheimer's disease', 'clinical trial', and 'humans', alone and in combinations, were incorporated into an electronic search strategy in both MEDLINE (National Library of Medicine, Bethesda, MD) and the Cochrane Register of Controlled Trials (The Cochrane Collaboration, Oxford, UK). As it emerges from this systematic review, the use of some phytochemicals and botanicals seems to be very promising in order to delay the onset and progression of neurodegenerative and other age-related diseases. However, further well-designed clinical research is certainly needed to finally confirm the efficacy and safety profile of these compounds.
... Improvement of memory L-theanine promotes the maturity of nervous centralis during the neural maturation period, which is beneficial for brain development [11,12] , ameliorates learning and memorizing ability by elimination of acquired memory disorders, oxidative stress, and improves the brain a-wave [66]. Cognitive functions can be enhanced by bioactive compound through the rise of brain neurotransmitters such as dopamine, 5-hydroxytryptamine (5-TH), glycine and g-aminobutyric acid (GABA) [67,68]. ...
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Natural bioactive compounds from plants are of great importance in modern therapeutics, which are used to prepare antibiotics, growth supplements or some other therapeutics. l-theanine is such a bioactive amide amino acid presented in different plants and fungi, especially in tea. Theanine has influential effects on lifestyle associated diseases, such as diabetes, cardiovascular disorders, hypertension, stress relief, tumor suppression, menstruation and liver injury. This amino acid can maintain normal sleep and improve memory function and nullify effect of the neurotoxins. The rate of bioavailability and its medium of ingestion in the body is one of the great concerns for its additional antioxidant properties. Pharmacokinetics of the bioactive compound and its mode of action are described herewith. The biosynthesis and industrial synthesis are also reviewed to promote accelerated production of this bioactive compound in the pharmaceutical industries.
... The antioxidant activities and positive effect of green tea could be linked its constituents such as l-theanine and caffeine which have clear beneficial effects on sustained attention, memory, and suppression of distraction. Moreover, l-theanine was found to lead to relaxation by reducing caffeine induced arousal [36]. Additionally, green tea polyphenols produced antidepressent like effect in adult mice [17]. ...
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Background Green tea extract (GTE) has various health promoting effects on animals and humans. However, the effects of perinatal exposure to GTE on the behavioral aspects of offspring have not been elucidated thus far. GTE was provided for pregnant female mice at concentrations of either 20 or 50 g/L, beginning the day of conception until the third week after delivery, postnatal day 22 (PD 22). Mice pups were subjected to behavioral testing to assess sensory motor reflexes, locomotion, anxiety, and learning on various postnatal days. Results Perinatal exposure to GTE resulted in a significant reduction in body weight, as well as earlier body hair appearance and opening of the eyes. Sensory motor reflexes exhibited faster responses and significant stimulatory effects in pups exposed to GTE. During the adolescent period, male and female offspring exhibited increased locomotor activity (on PD 22), reduced anxiety and fear (on PD 25), and enhanced memory and learning abilities (on PD 30), all in both GTE treated groups. All blood counts (RBCs, WBCs, Hb, and platelets), and glucose, cholesterol, triglyceride, and low density lipoprotein concentrations were significantly lower in the GTE-treated pups; however, there was no effect on high density lipoprotein levels. Conclusion Our data provide evidence that the high dose of GTE (50 g/L) had higher anxiolytic properties and positive effects on locomotor activities and sensory motor reflexes, as well as learning and memory of the offspring than the low dose of GTE (20 g/L).
... According to K Nieber, drinking coffee stimulates the human central nervous system and drinking up to 4 cups of coffee per day (about 400 mg of caffeine) is suitable for good health [17]. In another research paper by Dietz, Christina, in a study of coffee-to-human cognition, pointed out that 40 mg of coffee is enough to affect attention levels [16]. In his paper, D. M. Alharbi compared the effects of two types of coffee on attention levels and found that Arabica coffee is more beneficial for increasing personal attention [14], Because of this discovery. ...
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This study focused on the impact of local Arabica coffee on the level of attention of individual brain waves, and how coffee affects Human EEG Frequency. Local Arabica coffee is adopted in this study as a medium to wake up the Beta wave. The Personal brainwave data is then recorded through EEG equipment and classified. The result showed that local coffee is helping to improve people's attention level — the study conducted on fifty participants: twenty-five males and twenty-five females aged between twenty to thirty years old. Brainwaves or Electroencephalography are collected twice before and after drinking coffee to compare the effects of Arabica on human brain waves by using NeuroSky mindwave mobile. The paired sample t-test test was employed for comparing two groups of Beta brainwaves experiment. Besides, the k-means algorithm is used to perform data mining on brain waves, and the differential brain wave signal data is clustered and divided into three levels. The experimental results showed that there was a statistically significant difference between the two paired samples. Therefore, the results confirmed that local Arabica coffee has a direct impact on personal attention.
... The putative effects of tea consumption on psychological states such as mood and cognitive function are attributed to their phytochemical constituents. Examples of such compounds include, inter alia, the methylxanthine, caffeine which as a central nervous system stimulant has been shown to increase alertness and concentration, notably through its antagonistic effects on adenosine A 1 and A 2A receptors [25]; the amino acid L-theanine which has been shown to have positive effects on mood such as increased calmness and cognitive performance, perhaps through modulation od GABA receptors [26] and various polyphenols with varied positive effects on brain function [11,[27][28][29][30]. Studies by Scholey et al. [31] and Okello et al. [32] demonstrated that supplementation with 300 mg of the tea constituent Epigallocatechin Gallate (EGCG) or consumption of either black or green tea increase the Electroencephalogram (EEG) spectral powers of Theta, Alpha and Beta brain wave activities, a potential indication of their putative anxiolytic, attention and concentration effects. ...
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Background: A number of studies have indicated a beneficial effect of tea consumption on the reduction of risk of cognitive impairment and dementia in older aged populations. However, there is a paucity of data on these associations in the very old, defined as individuals aged 85 years and over. We investigated the relationship between tea consumption in the very old and measures of global cognitive function, memory, attention and psychomotor speed. Method: Longitudinal (5-years), population-based cohort study of individuals aged 85+ years in the North East of England, United Kingdom. Participants were community-dwelling and institutionalized men and women recruited through general medical practices (n=676). Baseline tea consumption and longitudinal measures of global and domain specific (memory, speed and attention) cognitive function were assessed. Linear mixed models, controlling for demographic (e.g. age, sex and education) and health variables were used to determine whether tea consumption was protective against cognitive decline. Results: Tea consumption was not associated with cognitive function at baseline on any measure (unadjusted and adjusted analyses). In the linear mixed effects models adjusted for age, sex, education and disease co-morbidity, higher tea consumption was associated with significantly better attention (focused and sustained attention), and psychomotor speed (complex tasks only) over five-years follow-up. However, there was no association between tea consumption and global cognitive function, memory or performance on simple speed tasks over time. Conclusions: In this cohort study of non-demented very old adults we found that higher (vs. lower) tea consumption was associated with better performance over time on measures of focused and sustained attention and some psychomotor speed tasks. No associations with global cognition, memory or easy speed tasks (simple Reaction Time or Word Recognition) were detected. The results have implications for the development of possible diet-based interventions focused on improving cognitive function in the very old age group. These findings need to be confirmed in a sufficiently powered and well-designed RCT with non-demented very old adults.
... 123 Die häufigsten beobachteten Effekte sind Wachheit, Reaktionsbereitschaft, Aufmerksamkeit und Gedächtnisleistung. 124 Theanin sorgt nicht nur für einen Anstieg der Neurotransmitter im Gehirn, sondern reguliert diese auch und verbessert somit die Signaltransduktion. 125 Somit kann das ZNS in einem physiologischen Gleichgewicht gehalten werden, welches unter dauerhaft stressigen Umständen gestört werden würde. ...
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Die hier vorgestellten Produkte mit Schwerpunkt Nachhaltigkeit und Evidenz-basierten Inhaltsstoffen (Energy-Drink & Protein-Riegel) erhalten im Verbrauchermarkt aufsteigendes Interesse. Dies liegt unter anderem daran, dass Nahrungsmittel mit gesundheits- und leistungsfördernden Eigenschaften benötigt werden, um der steigenden Anzahl an Krankheiten präventiv entgegenzuwirken. Besonders wichtig ist die adäquate Zufuhr von Proteinen und sekundären Pflanzenstoffe, um langfristig gesund zu bleiben. Im Gegensatz zu anderen bereits bestehenden Unternehmen liegt der Fokus dieses Konzepts auf der wissenschaftlichen Bestätigung zur Wirksamkeit der einzelnen Inhaltsstoffe. Damit soll dem Käufer ein optimales Preis-Leistungsverhältnis, auch in Bezug auf den Geschmack, geboten werden. Zusätzlich steht der Ressourcen-schonende Umgang mit Rohstoffen und Verpackungsmaterialien im Vordergrund, sodass zukunftsfähiges Handeln ermöglicht wird. Gerade in einer Zeit von hohen menschengemachten Umweltbelastungen, wie beispielsweise durch Plastikaufkommen in den Meeren, ist eine moralische Firmenpolitik notwendiger denn je.
... Although caffeine has been primarily associated with increased alertness, L-theanine appears to have the opposite effects, increasing relaxation and calm, but L-Complimentary Copy theanine appears to exert its most beneficial effect in combination with caffeine. For example, consumption of L-theanine and caffeine resulted in a better attention shifting effect compared to just caffeine (Dietz and Dekker 2017). Although most beneficial effects should be attributed to caffeine and its dose, the antagonism of L-theanine can reduce unpleasant side effects such as the jittery sensation of caffeine. ...
... In contrast, L-theanine leads to relaxation by reducing caffeine-induced arousal [123] ( Table 3). The cognitive effects of green tea are related to the combined effects of caffeine and L-theanine, while separate administration of each substance has been shown to have a smaller effect [124] (Table 3). In another study, Zaragoza et al. attempted to test the effect of supplementation with a low-dose combination of caffeine, theanine, and tyrosine on sport-specific cognition in tests where accuracy of movement and reaction time are important. ...
Article
Factors influencing brain function and cognitive performance can be critical to athletic performance of esports athletes. This review aims to discuss the potential beneficial effects of micronutrients, i.e., vitamins, minerals and biologically active substances on cognitive functions of e-athletes. Minerals (iodine, zinc, iron, magnesium) and vitamins (B vitamins, vitamins E, D, and C) are significant factors that positively influence cognitive functions. Prevention of deficiencies of the listed ingredients and regular examinations can support cognitive processes. The beneficial effects of caffeine, creatine, and probiotics have been documented so far. There are many plant products, herbal extracts, or phytonutrients that have been shown to affect precognitive activity, but more research is needed. Beetroot juice and nootropics can also be essential nutrients for cognitive performance. For the sake of players' eyesight, it would be useful to use lutein, which, in addition to improving vision and protecting against eye diseases, can also affect cognitive functions. In supporting the physical and mental abilities of e-athletes the base is a well-balanced diet with adequate hydration. There is a lack of sufficient evidence that has investigated the relationship between dietary effects and improved performance in esports. Therefore, there is a need for randomized controlled trials involving esports players.
... In contrast to our study, other cohort studies in elderly Asian adults reported less cognitive decline with higher green tea intake [21,86] rich in antioxidant, anti-inflammatory, and neuroprotective phytochemicals such as flavonoids, catechins [87][88][89], and caffeine [71,72]. In our study higher green tea intake were not significantly associated with incident AD or memory decline. ...
... The relatively high theanine content in matcha tea is responsible for its unique non-bitter taste, and in combination with caffeine provides the taste sensation and umami characteristic of this type of tea [48,50]. The combination of l-theanine and caffeine may enhance concentration, vigilance and efficiency to a higher extent than the use of either compound alone [51], additionally alleviating stress [49]. ...
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Japanese matcha is a type of powdered green tea, grown in a traditional way. Shading of the plants during the growth period enhances the processes of synthesis and accumulation of biologically active compounds, including theanine, caffeine, chlorophyll and various types of catechins. Green tea contains four main catechins, i.e., (−)-epicatechin (EC), (−)-epicatechin-3-gallate (ECG), (−)-epigallocatechin (EGC) and (−)-epigallocatechin-3-gallate (EGCG), of which the latter is the most active and abundant and matcha is their best condensed source. Due to its unique chemical composition and prized flavour, which sets it apart from other tea beverages, it is considered the highest quality tea. Its health-promoting properties are attributed to the high content of antioxidant and anti-inflammatory substances. Studies confirming the high antioxidant potential of tea beverages claim that it originates from the considerable content of catechins, a type of phenolic compound with beneficial effects on human health. Due to its potential for preventing many diseases and supporting cognitive function, regular consumption of matcha may have a positive effect on both physical and mental health. The aim of this review was to compile the health benefits of matcha tea. It is the first such review to be undertaken, and presents its main bioactive compounds in a systematic manner
... Il n'est donc pas surprenant que certaines plantes et épices contenant des flavonoïdes soient utilisées depuis des milliers d'années dans la médecine traditionnelle orientale. Nous pouvons citer à titre d'exemple le gallate d'épigallocatéchine (EGCG) contenu dans le thé vert et connu pour ses puissantes propriétés antioxydantes(Dietz and Dekker, 2017). Cette molécule a par ailleurs fait l'objet d'études cliniques menées chez des patients adultes atteints d'obésité et de sclérose en plaque(Mähler et al., 2015 ;Mielgo-Ayuso et al., 2014). ...
Thesis
La maladie d’Alzheimer (MA) est actuellement considérée comme la maladie neurodégénérative la plus fréquente. Son incidence est en nette augmentation, du fait du vieillissement croissant de la population et de traitements inefficaces. Elle touche aujourd’hui presque 50 millions de personnes dans le monde dont près de 1,2 millions de Français. Environ 225 000 nouveaux cas sont diagnostiqués en France chaque année, faisant de cette maladie neurodégénérative la quatrième cause de mortalité dans ce pays. Actuellement, il n’existe aucun traitement curatif de la maladie. Les polyphénols naturels, décrits comme possédant de multiples propriétés, pourraient être des molécules candidates pour le traitement de la MA. En effet, elles ont notamment des activités anti-inflammatoires, inhibitrices de l’agrégation du peptide amyloïde et sont capables de le désagréger. Ainsi, le resvératrol, polyphénol de référence, a été largement étudié dans des modèles cellulaires et animaux ainsi que chez le patient atteint de la MA. Malheureusement, il est très rapidement métabolisé et doit donc être administré à de très fortes doses pour être efficace. La viniférine, dimère naturel du resvératrol extraite à partir des sarments de vigne, pourrait ainsi, de par sa structure chimique, présenter des effets bénéfiques supérieurs à ceux du resvératrol.Dans une étude antérieure réalisée au laboratoire sur un modèle de souris transgénique de la MA, les souris APPswePS1dE9, il a été montré que la viniférine, administrée de façon hebdomadaire par voie intrapéritonéale (i.p.), conduisait à une réduction de la taille et de la densité des dépôts amyloïdes ainsi que de la neuroinflammation dans le cerveau des souris. Cependant, ces effets bénéfiques n'ont pas été comparés à ceux du resvératrol. De plus, l’effet de la viniférine sur le déclin cognitif n'a pas été évalué.L’objectif de cette thèse était donc de comparer les éventuels effets préventifs et/ou curatifs de la viniférine et du resvératrol dans ce modèle murin de la MA sur les dépôts amyloïdes et la neuroinflammation, ainsi que sur le déclin cognitif. Dans une première étude, des souris APPswePS1dE9 ou sauvages ont été traitées par une injection i.p. hebdomadaire de viniférine ou de resvératrol à la dose de 20 mg/kg ou par leur véhicule, le polyéthylène glycol 200 (PEG 200) entre 7 et 11 mois, afin d’évaluer la capacité de ces polyphénols à ralentir l’évolution de la maladie. À 7 mois, les principales lésions caractéristiques de la MA sont déjà présentes chez ces souris. Dans une seconde étude, l’effet préventif des polyphénols injectés de 3 à 12 mois chez ces souris a été recherché (aucune lésion à 3 mois). Dans ces 2 études in vivo, l’évolution du statut cognitif des souris a été évaluée grâce au test comportemental de la piscine de Morris. La charge amyloïde, les dépôts amyloïdes et la neuroinflammation ont été quantifiés par western-blot, ELISA, immunofluorescence et TEP-scan.Les résultats ont montré que la viniférine diminuait le taux des formes insolubles d’Aβ42 et d’Aβ40 et les dépôts amyloïdes hippocampiques avec une meilleure efficacité que le resvératrol à 11 mois. De plus, les deux polyphénols ont prévenu partiellement le déclin cognitif. En revanche, ces polyphénols n’ont pas corrigé la neuroinflammation. Ce dernier résultat peut s’expliquer par l’effet pro-inflammatoire du PEG 200, inconnu jusqu’à présent, dans l’hippocampe des souris sauvages traitées par celui-ci. Le traitement par la viniférine de 3 à 12 mois induit aussi une diminution des dépôts amyloïdes. Toutefois, aucun effet sur le déclin mnésique et la neuroinflammation n’est observé. L’effet secondaire du PEG 200 peut masquer l’effet de la viniférine sur les processus inflammatoires et la perte mnésique. D’autres études sont nécessaires avec un autre véhicule ainsi qu’une analyse approfondie de la signature des oligomères pour juger réellement des effets de la viniférine sur la composante amyloïde dans la MA.
... The putative effects of tea consumption on psychological states such as mood and cognitive function are attributed to their phytochemical constituents. Examples of such compounds include, inter alia, the methylxanthine, caffeine which as a central nervous system stimulant has been shown to increase alertness and concentration, notably through its antagonistic effects on adenosine A 1 and A 2A receptors [25]; the amino acid Ltheanine which has been shown to have positive effects on mood such as increased calmness and cognitive performance, perhaps through modulation od GABA receptors [26] and various polyphenols with varied positive effects on brain function [11,[27][28][29][30]. Studies by Scholey et al. [31] and Okello et al. [32] demonstrated that supplementation with 300 mg of the tea constituent Epigallocatechin Gallate (EGCG) or consumption of either black or green tea increase the Electroencephalogram (EEG) spectral powers of Theta, Alpha and Beta brain wave activities, a potential indication of their putative anxiolytic, attention and concentration effects. ...
Article
Full-text available
Background A number of studies have indicated a beneficial effect of tea consumption on the reduction of risk of cognitive impairment and dementia in older aged populations. However, there is a paucity of data on these associations in the very old, defined as individuals aged 85 years and over. We investigated the relationship between tea consumption in the very old and measures of global cognitive function, memory, attention and psychomotor speed. Method Longitudinal (5-years), population-based cohort study of individuals aged 85+ years in the North East of England, United Kingdom. Participants were community-dwelling and institutionalized men and women recruited through general medical practices ( n = 676). Baseline tea consumption and longitudinal measures of global and domain specific (memory, speed and attention) cognitive function were assessed. Linear mixed models, controlling for demographic (e.g. age, sex and education) and health variables were used to determine whether tea consumption was protective against cognitive decline. Results Tea consumption was not associated with cognitive function at baseline on any measure (unadjusted and adjusted analyses). In the linear mixed effects models adjusted for age, sex, education and disease co-morbidity, higher tea consumption was associated with significantly better attention (focused and sustained attention), and psychomotor speed (complex tasks only) over five-years follow-up. However, there was no association between tea consumption and global cognitive function, memory or performance on simple speed tasks over time. Conclusions In this cohort study of non-demented very old adults we found that higher (vs. lower) tea consumption was associated with better performance over time on measures of focused and sustained attention and some psychomotor speed tasks. No associations with global cognition, memory or easy speed tasks (simple Reaction Time or Word Recognition) were detected . The results have implications for the development of possible diet-based interventions focused on improving cognitive function in the very old age group. These findings need to be confirmed in a sufficiently powered and well-designed RCT with non-demented very old adults.
Article
Neurodegenerative and neuropsychiatric diseases have attracted global attention with an overwhelming burden on families and society. Tea contains many bioactive compounds, such as polyphenols and theanine, which could contribute to the neuroprotective effects of tea. The possible mechanisms of action include regulating signaling pathways and gut microbiota; inhibiting abnormal protein aggregation; normalizing the hyperactivity of the hypothalamic-pituitary-adrenal axis; as well as antioxidant and anti-inflammatory properties of tea for Parkinson’s disease, Alzheimer’s disease, and depression. In this narrative revie w, the effects of tea on these diseases were summarized, and special attention was paid to the mechanisms of action. Abbreviations: AChE, acetylcholinesterase; ACTH, adrenocorticotropin; AKT, serine-threonine protein kinase; BChE, butyrylcholinesterase; BDNF, brain-derived neurotrophic factor; CI, confidence interval; COX-2, cyclooxygenase-2; CRH, corticotrophin-releasing hormone; CREB, cyclic adenosine monophosphate response element-binding protein; EC, epicatechin; ECG, epicatechin-3-gallate; EGC, epigallocatechin; EGCG, epigallocatechin gallate; ERK, extracellular signal-regulated kinase; GABA, gamma-aminobutyric acid; GSK-3β, glycogen synthase kinase-3β; HPA, hypothalamic-pituitary-adrenal; HR, hazard ratio; IL, interleukin; MAOB, monoamine oxidase B; MPTP, 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine; NFκB, nuclear factor kappa-light-chain-enhancer of activated B cells; Nrf2, nuclear factor erythroid 2-related factor 2; NOS, nitric oxide species; OR, odds ratio; PGC-1α; peroxisome proliferator-activated receptor gamma coactivator-1α; PI3K, phosphoinositide 3-kinase; PKC, protein kinase C; ROS, reactive oxygen species; RR, risk ratio; TLR4, Toll-like receptor 4; TNF-α; umor necrosis factor alpha; 6-OHDA, 6-hydroxydopamine.
Chapter
In diesem Kapitel … findest du viele nützliche Tipps für deine Ernährung. Wir vernachlässigen unser Gehirn und denken selten darüber nach, welchen Einfluss unser Essen auf unser Gehirn hat. Eine gesunde Ernährung ist nicht nur wichtig für die körperliche Gesundheit, sondern laut unzähligen Studien auch absolut wichtig für eine optimale und gesunde Gehirnfunktion. Mit welchen Nahrungsmitteln können wir unsere Leistung und geistige Gesundheit verbessern? Eines ist klar: Unter Fast Food leidet unser Gehirn. Gehen wir der Sache auf den Grund gehen und finden heraus, von welchen Lebensmitteln wir lieber die Finger lassen und bei welchen Nahrungsmitteln wir öfters zugreifen sollten.
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In recent decades, preclinical research into natural products has focused on the identification of pharmacologically active secondary metabolites produced by plants, often traditionally used as medicinal remedies. Beyond vitamins and minerals, plants contain other secondary metabolites recently defined as “nutraceuticals,” which are at the center of important scientific studies. The term nutraceutical is a portmanteau word, a combination of “nutrition” and “pharmaceutical,” and refers to “naturally derived bioactive compounds that are found in foods, dietary supplements, and herbal products and have health-promoting, disease-preventing, and/or medicinal properties.” Several nutraceuticals exhibit antiaging features by acting on the inflammatory status and on the prevention of oxidative reaction. This results in a significant reduction of all risk factors for age-related diseases, enhancing the attainment of healthy aging. In this context, the chapter will summarize the available clinical evidence supporting the use of selected botanicals and phytochemicals with confirmed activity on the human central nervous system and demonstrated effects in modulating cognitive decline as an example of age-related disease. In particular, the chapter will focus on data supporting the potential usefulness of Ginkgo biloba, Vitis vinifera, Camellia sinensis, Theobroma cacao, Bacopa monnieri, Crocus sativus, and Curcuma longa.
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Negative emotions and sleep disorders are common health-related concerns faced by many people who live under some sort of pressure in modern society. In the long run, these issues can decline the immunity of a person, which in turn is closely related to the inflammatory signaling pathway that affects the brain. Clinical evidence suggests that the intestinal flora can regulate the host’s sleep and emotional status through the brain intestinal axis. As a dietary factor, tea polyphenols (TP) play a role in regulating mood and sleep. On the one hand, the intestinal flora can promote the metabolism and absorption of TP in the body to thereby improve their bioavailability. On the other hand, TP can modify the abundance of intestinal flora, improve the composition of beneficial flora and inhibit the growth of harmful bacteria. Considering that the epidemiological causes of anxiety, depression and sleep disorders involve the interaction of environmental stress and genetic predisposition in various physiological systems, treatment options that combine the intestinal microbiota and TP may prove superior to the classical pharmacological treatments because intestinal microbiota promotes the production of a variety of bioactive metabolites from dietary polyphenols that can simultaneously regulate the moods and sleep to improve the immunity. In this review, we discussed the relationship among TP, intestinal flora, emotion and sleep, as well as their interactions that promote the effective regulation of emotion and sleep, to ultimately improve the body’s immunity.
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Tea consumption has been extensively shown to be closely related to physical health and cognitive abilities. However, there are no definite conclusions on the relationship between tea consumption and convergent thinking. Convergent thinking requires top-down cognitive processing, which focuses on searching for an appropriate idea based on well-defined criteria. It is a necessary part of the creative process and is inextricably linked to divergent thinking that requires people to search for many different ideas with less defined criteria within a wider search span. It has been found that tea consumption is beneficial to divergent thinking in creativity. Given that convergent thinking is related to divergent thinking, we hypothesized that drinking tea may also promote convergent thinking. This research was to investigate the enhancing effects of tea on convergent thinking and test its possible mediating mechanism (i.e., the role of positive emotions) and marginal conditions (e.g., the moderating roles of intelligence and tea preference). In Experiment 1, participants completed the Remote Associates Test (RAT) which requires the solver to create a meaningful link (word association) that mediates three seemingly unrelated cues (e.g., Same–Tennis–Head is mediated by Match) after drinking tea or water. The results showed that the type of drinks and tea consumption habits had a significant interaction effect on RAT scores. The participants who drank tea (v.s. water) performed best in the RAT. A “split half effect” was found. That is, participants' performance in different groups was significantly different in the second half of the RAT, suggesting that drinking tea leads to persistent problem-solving convergent thinking. Experiment 2 aimed to replicate the findings in Experiment 1 using a different convergent thinking task, namely, riddle tasks, where participants needed to solve riddles with different levels of difficulty. The results revealed that performance in the tea group on the difficult tasks was significantly higher than that in the water group; after controlling for knowledge level and intelligence, the differences in the performance in the medium- and high-difficulty riddle tasks between the two groups were significant. Although no experiments found a mediating effect of positive emotions, Experiment 2 showed that the participants in the tea group were happier and more interested in the task than those in the water group. To conclude, the positive effects of tea drinking on convergent thinking was demonstrated, and the moderating effects of knowledge level, intelligence, and tea drinking habits were elaborated. The results have important practical significance for those who are engaged in creative work or those who are prone to fatigue.
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Alzheimer's disease (AD) is the most common form of dementia in elderly people with a high incidence rate and complicated pathogenesis, and causes progressive cognitive deficit and memory impairment. Some natural products and bioactive compounds from natural sources show great potential in the prevention and treatment of AD, such as apple, blueberries, grapes, chili pepper, Monsonia angustifolia, cruciferous vegetables, Herba epimedii, Angelica tenuissima, Embelia ribes, sea cucumber, Cucumaria frondosa, green tea, Puer tea, Amanita caesarea and Inonotus obliquus, via reducing amyloid beta (Aβ) deposition, decreasing Tau hyperphosphorylation, regulating cholinergic system, reducing oxidative stress, inhibiting apoptosis and ameliorating inflammation. This review mainly summarizes the effects of some natural products and their bioactive compounds on AD with the potential molecular mechanisms.
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The imbalance of intestinal microbiota can cause the accumulation of endotoxin in the main circulation system of the human body, which has a great impact on human health. Increased work and life pressure have led to a rise in the number of people falling into depression, which has also reduced their quality of life. The gut–brain axis (GBA) is closely related to the pathological basis of depression, and intestinal microbiota can improve depressive symptoms through GBA. Previous studies have proven that prebiotics can modulate intestinal microbiota and thus participate in human health regulation. We reviewed the regulatory mechanism of intestinal microbiota on depression through GBA, and discussed the effects of prebiotics, including plant polysaccharides and polyphenols on the regulation of intestinal microbiota, providing new clues for the prevention and treatment of depression.
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Depression is a global public health issue with high morbidity and mortality, which tends to cause fatigue, inability to concentrate, insomnia, and loss of appetite, especially represented by major depressive disorder (MDD). Pathologically, depression is associated with hyperactivity of hypothalamic–pituitaryadrenal (HPA) axis, inflammation, loss of monoaminergic system, and disturbance of gut microbiota. Epidemiological studies have shown that regular tea drinking can reduce the risk of depression. Tea bioactive compounds (L-theanine, catechin, tea pigment and GABA) can regulate depression by inhibiting hyperactive HPA axis, reducing the inflammatory response, restoring the monoaminergic system, inhibiting monoamine oxidase levels, increasing the enrichment of intestinal flora and promoting microbial-gut-brain axis activity. This review discusses the composition, structure, bioavailability and safety of bioactive components from tea, and focuses on exploring the possible pathways of tea bioactive compounds in the regulation of depression. In addition, the low bioavailability of natural bioactive compounds from tea limits the efficacy on depression. Emerging technologies (such as metabolomics, proteomics, and genomics) and nano-encapsulation can be utilized to improve the stability and bioavailability of tea active ingredients, and reduce the potential biotoxicity. The review provides a theoretical basis of utilization of tea active compounds for formulating the prevention and treatment of depression.
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Yellow tea, a rare type tea from China, has a rich breadth of functional ingredients and benefits the gastrointestinal tract. However, it is not clear whether the yellow tea extract can alleviate constipation. Therefore, we used loperamide-induced constipation in mice to evaluate the effects of yellow tea extract. Fifty Kunming mice were randomly divided into five groups: normal, model, low-dose yellow tea extract, low-dose yellow tea extract prevention group, and high-dose yellow tea extract prevention group. Mice were administered yellow tea extract for 5 weeks followed by loperamide-induced constipation for the final 2 weeks. The results showed that yellow tea extract alleviated constipation symptoms by improving the fecal water content, defecation weight, and gastrointestinal transit rate. Yellow tea extract intervention also protected colon tissue, regulated serum neurotransmitters, and decreased the vasoactive intestinal peptide level. Furthermore, qRT-PCR indicated that yellow tea extract regulated genes associated with the constipation state, raised 5-HT3 and 5-HT4 and reduced AQP3 and AQP4 mRNA expression. Moreover, we found that yellow tea extract changed the gut microbiota composition. Community diversity and richness were increased and principal co-ordinate analysis demonstrated that the yellow tea extract prophylaxis groups differed from the model group. Difference analysis indicated that yellow tea extract increased Roseburia, Lachnospiraceae_UCG-006, and Bifidobacterium and decreased norank_f_Clostridiales_vadinBB60_group, unclassified_o_Bacteroidales, and Bacteroides, which are correlated with constipation. Based on these results, we believe that regular yellow tea consumption can effectively alleviate constipation.
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Tea is the world’s favorite beverage; thus, any health-related psychological or physiological consequences of drinking tea could have considerable impact. Although tea is available in many forms, “true” teas all derive from the tea plant, Camellia sinensis: the variety of beverages reflects primarily how the leaves are processed and fermented. For example, green tea is essentially unfermented, whereas black tea is extensively fermented. Tea contains many chemicals with potential for biological activity; in particular, the flavonoids, e.g. catechins, have good antioxidant capability in vitro. In the laboratory, these components, and tea itself, may suppress the damaging activity of free radicals, reduce inflammation and risk of blood clotting, and improve the responsiveness of blood vessel walls to changes in blood flow. Consequently, in studies dissociating other lifestyle factors, tea drinking seems to reduce cardiovascular disease risk.Despite promising laboratory evidence, observational studies of effects of normal tea drinking in large populations and its relation to cancer incidence have been inconsistent. One reason could be that, to protect against cancer, tea may need to be drunk at quite a high level and by populations that eat relatively low amounts of fruit and vegetables, i.e. tea might particularly lower cancer risk in those with an otherwise unhealthy diet.Drinking green tea or tea catechins has been studied for any impact on body weight and body fat: there is evidence that these can be reduced by such treatment in overweight or obese people, potentially by stimulating fat oxidation.Tea appears to have subtle effects on the brain, including aiding recovery from stress, and has been linked to resistance to depression, possibly via effects of the amino acid, theanine, which is known to alter brain electrical activity. This, together with mood and performance effects, suggests that tea may promote a more relaxed state that improves sustained attention. Theanine also interacts with caffeine, so that the combination produced better performance than either alone; theanine suppressed the rise in blood pressure caused by caffeine. In addition to short-term benefits for brain function, tea may protect nerve cells from damage, and promote their growth, suggesting protection against neurodegenerative diseases. Population-based studies show delayed cognitive decline in elderly tea drinkers, and reduced risk of Parkinson’s disease. Therefore, although more research is needed, evidence suggests that habitual tea drinking may benefit both the cardiovascular system and the brain, and improve our physical and psychological health.
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Green tea's popularity can be largely attributed to its potential health benefits, with an emphasis on antioxidant properties from its catechin constituents, especially ()-epigallocatechin-3-gallate (EGCG). EGCG appears to be responsible for many of the potential health benefits of green tea. However, while higher intake levels may provide benefit, lower intake levels may not. The objective was to determine whether commercially available green tea products provide label information about EGCG content and other constituents and then to analyze the label information in terms of existing research. A descriptive analysis of product label information was conducted. In total, 105 green tea products evaluated, 58% of green tea supplements and 5% of green tea beverages included information about EGCG content on the label. Among the dietary supplement products providing sufficient information on the label, the amount of EGCG listed ranged from 70 mg to 600 mg per serving. The average EGCG per serving was 223.7 mg. The average reported caffeine content was 56.0 mg per serving. In conclusion, most green tea beverages to not provide adequate information about EGCG or other constituents. Green tea supplements are more likely to provide this information. One to two servings of green tea supplements are typically needed to achieve EGCG or catechin intake levels similar to those demonstrating efficacy in clinical studies. Consumers should consider selecting products that adequately describe constituent information on the label. Manufacturers should consider providing this essential information on the product label in order to better inform consumer decision-making.
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Evidence suggests interactive effects of the tea components caffeine and L-theanine on behaviour, yet no data exists exploring the impact of the two on cerebral blood flow (CBF). The current placebo-controlled, double-blind, counterbalanced, crossover study examined the effects of caffeine and L-theanine on CBF and extended previous cognitive and mood findings by using lower doses than previous studies of a similar methodology, which more closely reflect the ratios present in tea. Twelve habitual consumers and 12 non-habitual consumers of caffeine each received 75 mg caffeine, 50 mg L-theanine, 75 mg caffeine plus 50 mg L-theanine, and placebo in a counterbalanced order across four separate visits. CBF was measured via near-infrared spectroscopy with cognition and mood assessed at baseline and 30 min post-dose. Salivary caffeine and peripheral haemodynamics were co-monitored. Caffeine reduced oxygenated haemoglobin (oxy-Hb), increased deoxygenated haemoglobin (deoxy-Hb), improved performance on attention tasks and increased overall mood ratings. Increases in deoxy-Hb following caffeine were more pronounced in non-consumers. Some evidence for increased deoxy-Hb remained when caffeine was combined with L-theanine, but this effect was attenuated and the effects of caffeine on oxy-Hb, cognition and mood were eradicated. Combining L-theanine with caffeine, at levels and ratios equivalent to one to two cups of tea, eliminated the vasoconstrictive effect and behavioural effects of caffeine. This supports previous findings of an interaction between these substances, despite a lack of effects of L-theanine in isolation. However, at the levels tested here, this did not lead to a positive impact on behaviour.
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Epigallocatechin gallate (EGCG) is a major polyphenol in green tea with beneficial effects on the impairment in learning and memory. Autophagy is a cellular process that protects neurons from stressful conditions. The present study was designed to investigate whether EGCG can rescue chronic unpredictable mild stress (CUMS)-induced cognitive impairment in rats and whether its protective effect involves improvement of autophagic flux. As expected, our results showed that CUMS significantly impaired memory performance and inhibited autophagic flux as indicated by elevated LC3-II and p62 protein levels. At the same time, we observed an increased neuronal loss and activated mammalian target of rapamycin (mTOR)/p70 ribosomal protein S6 kinase (p70S6k) signaling in the CA1 regions. Interestingly, chronic treatment with EGCG (25 mg/kg, i.p.) significantly improved those behavioral alterations, attenuated histopathological abnormalities in hippocampal CA1 regions, reduced amyloid beta1-42 (Aβ1-42) levels, and restored autophagic flux. However, blocking autophagic flux with chloroquine, an inhibitor of autophagic flux, reversed these effects of EGCG. Taken together, these findings suggest that the impaired autophagy in CA1 regions of CUMS rats may contribute to learning and memory impairment. Therefore, we conclude that EGCG attenuation of CUMS-induced learning and memory impairment may be through rescuing autophagic flux.
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While the impact of interactions between flavan-3-ol and protein on food quality has been reported, the ability of these interactions to modify flavan-3-ol bioavailability remains unclear. The objectives of this study were to characterize the influence of milk proteins and mineral components of the milk matrix on in vitro bioaccessibility of green tea flavan-3-ols and to assess the relative impact of protein digestibility in the GI tract on protein-flavan3-ol binding. Protein solutions containing sodium-caseinate (S-CSN, 35.6 mg/mL), alpha-lactalbumin (alpha-LA, 1 mg/mL), p-lactoglobulin (beta-LG, 3.5 mg/mL), or non-fat dry milk (NFDM) were prepared in Jenness Koops (JK) buffer containing milk salts and formulated at 10-40% (v/v) into green tea beverages containing 0.6 mg/mL total flavan-3-ols. Samples were subjected to a three-stage in vitro digestion to assess flavan-3-ol digestive release and stability (bioaccessibility). Milk protein, most notably S-CSN, significantly decreased (p <0.05) bioaccessibility of flavan-3-ols relative to JK buffer controls (10 relative to 32%). Interestingly, the presence of milk minerals significantly increased (p < 0.05) flavan-3-ol bioaccessibility compared to that of controls (32 relative to 18%). These data combined with SDS-PAGE and fluorometric analyses suggest that both milk proteins and minerals may alter flavan-3-ol bioaccessibility, but normal GI digestion appears to minimize the impact of specific protein interactions. (C) 2014 Published by Elsevier Ltd.
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Human cognitive performance is widely perceived to be enhanced by caffeine at usual dietary doses. However, the evidence for and against this belief continues to be vigorously contested. Controversy has centred on caffeine withdrawal and withdrawal reversal as potential sources of experimental confounding. In response, some researchers have enlisted "caffeine-naïve" experimental participants (persons alleged to consume little or no caffeine) assuming that they are not subject to withdrawal. This mini-review examines relevant research to illustrate general methodological challenges that have been the cause of enduring confusion in caffeine research. At issue are the processes of caffeine withdrawal and withdrawal reversal, the definition of caffeine-naïve, the population representativeness of participants deemed to be caffeine-naïve, and confounding due to caffeine tolerance. Attention to these processes is necessary if premature conclusions are to be avoided, and if caffeine's complex effects and the mechanisms responsible for those effects are to be illuminated. Strategies are described for future caffeine research aimed at minimising confounding from withdrawal and withdrawal reversal.
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Green tea is a rich source of the strong antioxidants, the catechins, but it also contains high levels of caffeine, which may cause negative effects in some people and this has led to a demand for decaffeinated green tea. Numerous decaffeination methods have been developed to remove caffeine from green tea. This article reviews these decaffeination methods and discusses their advantages and limitations for future consideration. In addition, there is also a need for isolation of caffeine from natural sources for utilization as an additive in the beverage and pharmaceutical industries. Furthermore, this article outlines the isolation methods of caffeine from green tea and discusses the potential for future studies.
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Green tea is rich in polyphenol flavonoids including catechins. Epigallocatechin 3-gallate (EGCG) is the most abundant and potent green tea catechin. EGCG has been extensively studied for its beneficial health effects as a nutriceutical agent. Based upon its chemical structure, EGCG is often classified as an antioxidant. However, treatment of cells with EGCG results in production of hydrogen peroxide and hydroxyl radicals in the presence of Fe (III). Thus, EGCG functions as a pro-oxidant in some cellular contexts. Recent investigations have revealed many other direct actions of EGCG that are independent from anti-oxidative mechanisms. In this review, we discuss these novel molecular mechanisms of action for EGCG. In particular, EGCG directly interacts with proteins and phospholipids in the plasma membrane and regulates signal transduction pathways, transcription factors, DNA methylation, mitochondrial function, and autophagy to exert many of its beneficial biological actions.
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The alerting effects of both caffeine and short wavelength (blue) light have been consistently reported. The ability of blue light to enhance alertness and cognitive function via non-image forming neuropathways have been suggested as a non-pharmacological countermeasure for drowsiness across a range of occupational settings. Here we compare and contrast the alerting and psychomotor effects of 240 mg of caffeine and a 1-h dose of ~40 lx blue light in a non-athletic population. Twenty-one healthy subjects performed a computer-based psychomotor vigilance test before and after each of four randomly assigned trial conditions performed on different days: white light/placebo; white light/240 mg caffeine; blue light/placebo; blue light/240 mg caffeine. The Karolinska Sleepiness Scale was used to assess subjective measures of alertness. Both the caffeine only and blue light only conditions enhanced accuracy in a visual reaction test requiring a decision and an additive effect was observed with respect to the fastest reaction times. However, in a test of executive function, where a distraction was included, caffeine exerted a negative effect on accuracy. Furthermore, the blue light only condition consistently outperformed caffeine when both congruent and incongruent distractions were presented. The visual reactions in the absence of a decision or distraction were also enhanced in the blue light only condition and this effect was most prominent in the blue-eyed participants. Overall, blue light and caffeine demonstrated distinct effects on aspects of psychomotor function and have the potential to positively influence a range of settings where cognitive function and alertness are important. Specifically, despite the widespread use of caffeine in competitive sporting environments, the possible impact of blue light has received no research attention.
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Caffeine is one of the most researched food components, with the vast majority of dietary contributions coming from beverage consumption; however, there is little population-level data on caffeine intakes in the U.S. This study estimated the caffeine intakes of the U.S. population using a comprehensive beverage survey, the Kantar Worldpanel Beverage Consumption Panel. A nationally representative sample of 37,602 consumers (aged ⩾2 years) of caffeinated beverages completed 7-day diaries which facilitated the development of a detailed database of caffeine values to assess intakes. Results showed that 85% of the U.S. population consumes at least one caffeinated beverage per day. The mean (±SE) daily caffeine intake from all beverages was 165±1 mg for all ages combined. Caffeine intake was highest in consumers aged 50-64 years (226±2 mg/day). The 90th percentile intake was 380 mg/day for all ages combined. Coffee was the primary contributor to caffeine intakes in all age groups. Carbonated soft drinks and tea provided a greater percentage of caffeine in the younger (<18 years) age groups. The percentage of energy drink consumers across all age groups was low (⩽10%). These data provide a current perspective on caffeinated beverage consumption patterns and caffeine intakes in the U.S. population.
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Tea has historically been associated with mood and performance benefits, such as relaxation and concentration. This review summarizes the research on the acute effects of tea, and its ingredients theanine and caffeine, on attention and mood. Consistent with abundant research on the benefits of caffeine, the performance benefits of tea were identified in a number of studies, with particularly consistent evidence for improved attention. Tea consumption also consistently improved self-reported alertness and arousal, whereas effects on pleasure or relaxation were less consistent. In addition to the research on caffeine in real-life performance, 2 recent studies have provided a broader perspective on tea's effects on psychological function in that they showed beneficial effects in related areas such as work performance and creativity. These studies showed the validity of laboratory findings by supporting the idea that tea consumption has acute benefits on both mood and performance in real-life situations.
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Written to educate both professionals and the general public, this article provides an update and overview of the field of neurofeedback (EEG biofeedback). The process of assessment and neurofeedback training is explained. Then, areas in which neurofeedback is being used as a treatment are identified and a survey of research findings is presented. Potential risks, side effects, and adverse reactions are cited and guidelines provided for selecting a legitimately qualified practitioner.
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Caffeine is the most popular psychoactive substance in the world, and one of the widest-traded commodities in the forms of coffee, tea and cola soft drinks. But is consumption of caffeine safe in terms of physical and mental health? Addressing this question, the author traces how caffeine consumption evolved as well as how caffeine is absorbed, distributed and metabolized in our bodies. He then discusses the effects of caffeine on: psychomotor and cognitive performance; psychological well-being; blood pressure and cardiovascular health; carcinogenic potentials; pregnancy and perinatal health; athletic performance; and diagnostic and therapeutic applications. The book addresses the question of whether caffeine is a drug of abuse, and summarizes the main conclusions to be drawn from the vast body of relevant science.
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Although college students’ caffeine consumption has increased over the last decade, studies have not yet determined the time frame in which caffeine exerts its effects nor the impact of the vehicle by which caffeine is consumed. Sixty college students were randomly divided into one placebo (flour) and three caffeine treatment groups: 5-Hour Energy ®, Starbucks DoubleShot ®, or caffeine powder; all dosed at 3 mg caffeine/kg of body weight. A battery of tests was performed prior to dosing and repeated 2.5 and 5 hours post treatment. Mood was self-reported on a scale of 1-100 for happiness, alertness and focus. Cognitive function was assessed by Stroop and memory tests. Reaction time, heart rate, blood glucose, and electroencephalogram were recorded. All initial measurements across groups and group baselines vs 2.5 and 5 hour results were analyzed by ANOVA followed, when indicated, by post hoc t-tests at 95% confidence levels and only significant results are reported. All caffeine groups had elevations in mood and faster reaction times at 2.5 hours (most effects sustained for 5 hours). The 5-Hour Energy® group rated alertness higher than other caffeine treatments, and was the only group to demonstrate decreases in alpha waves, memory improvements, and impaired glucose homeostasis. All caffeine groups had improved cognition with decreased Stroop test time and the caffeine powder and 5-Hour Energy ® groups had improved Stroop test accuracy at 2.5 hours. The 5-Hour Energy shot ® had the greatest proportion of sustained caffeine effects across test parameters.
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Beverages play a major role in determining nutritional health. Indeed, water represents as much as 60 % of the body weight in a lean person but only 45 % in the obese. Water from a tap or bottle remains the most popular beverage on the planet. Determining the nutritional consequences of a beverage is complicated by the myriad of additional contents mixed in with our water. Nonalcoholic beverages include coffee, tea, milk, juices, soft drinks, energy drinks, sports drinks, drinks for weight management, and of course water. Beverages provide about one-fifth of our daily energy intake, with the greatest intake occurring in 19- to 39-year olds [1]. These beverages may contain sugars, fats, minerals, and vitamins from natural or supplemental origin; these substances can alter the taste and nutritional consequences of beverages. Alcohol is another potential ingredient in beverages which can have dramatic health consequences. Alcoholic beverages were covered in the previous chapter.
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There is clear evidence that the prefrontal cortex is strongly involved in executive processes and that dopamine can influence performance on working memory tasks. Although, some studies have emphasized the role of striatal dopamine in executive functions, the role played by prefrontal dopamine during executive tasks is unknown. In order to investigate cortical dopamine transmission during executive function, we used D-2-dopamine receptor ligand [C-11] FLB 457 PET in healthy subjects while performing the Montreal Card Sorting Task (MCST). During the retrieval with shift task of the MCST, the subjects had to match each test card to one of the reference cards based on a classification rule (color, shape or number) determined by comparing the previously viewed cue card and the current test card. A reduction in [C-11] FLB 457 binding potential in the right dorsal anterior cingulate cortex (ACC) was observed when subjects performed the active task compared to the control task. These findings may suggest that right dorsal ACC dopamine neurotransmission increases significantly during the performance of certain executive processes, e. g., conflict monitoring, in keeping with previous evidence from fMRI studies showing ACC activation during similar tasks. These results may provide some insights on the origin of cognitive deficits underlying certain neurological disorders associated with dopamine dysfunction, such as Parkinson's disease and schizophrenia.
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Green tea is usually prepared by adding boiling water to dried tea leaves, which aremade from the plant Camellia Sinensis. Worldwide, tea is the second most popularbeverage after water. Similar to alcohol and coffee, drinking of green tea can producepleasant feelings. In other words, consumption of green tea is partly due to its biologicaleffects on cognitive function and emotions. To date, extensive epidemiological, clinicaland experimental studies have shown that green tea drinking is beneficial to many aspectsof physical health. There is also emerging evidence suggesting that key compounds ofgreen tea may promote mental status and health of the central nervous system. The mostpromising candidates are L-theanine and green tea catechins. This commentary reviewsrecent findings from experimental and epidemiological studies on the neurological effectsof green tea, and discusses possible mechanisms of action.
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Stress induces reactive oxygen species (ROS) and causes alterations in brain cytoarchitecture and cognition. Green tea has potent antioxidative properties especially the tea catechin (-) epigallocatechin-3-gallate (EGCG). These powerful antioxidative properties are able to protect against various oxidative damages. In this study we investigated the impact of stress on rats' locomotor activity, learning and memory. Many tea catechins, including EGCG, were examined for their possible therapeutic effects in treating stress-induced impairment. Our results indicated that locomotor activity was decreased, and the learning and memory were impaired in stressed rats (SRs). EGCG treatment was able to prevent the decreased locomotor activity as well as improve the learning and memory in SRs. EGCG treatment was also able to reduce the increased oxidative status in SRs' hippocampi. The above results suggest a therapeutic effect of EGCG in treating stress-induced impairment of learning and memory, most likely by means of its powerful antioxidative properties. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.
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The original central fatigue hypothesis suggested that an exercise-induced increase in extracellular serotonin concentrations in several brain regions contributed to the development of fatigue during prolonged exercise. Serotonin has been linked to fatigue because of its well known effects on sleep, lethargy and drowsiness and loss of motivation. Several nutritional and pharmacological studies have attempted to manipulate central serotonergic activity during exercise, but this work has yet to provide robust evidence for a significant role of serotonin in the fatigue process. However, it is important to note that brain function is not determined by a single neurotransmitter system and the interaction between brain serotonin and dopamine during prolonged exercise has also been explored as having a regulative role in the development of fatigue. This revised central fatigue hypothesis suggests that an increase in central ratio of serotonin to dopamine is associated with feelings of tiredness and lethargy, accelerating the onset of fatigue, whereas a low ratio favours improved performance through the maintenance of motivation and arousal. Convincing evidence for a role of dopamine in the development of fatigue comes from work investigating the physiological responses to amphetamine use, but other strategies to manipulate central catecholamines have yet to influence exercise capacity during exercise in temperate conditions. Recent findings have, however, provided support for a significant role of dopamine and noradrenaline (norepinephrine) in performance during exercise in the heat. As serotonergic and catecholaminergic projections innervate areas of the hypothalamus, the thermoregulatory centre, a change in the activity of these neurons may be expected to contribute to the control of body temperature whilst at rest and during exercise. Fatigue during prolonged exercise clearly is influenced by a complex interaction between peripheral and central factors.
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Matcha is a kind of Japanese green tea that is traditionally used for the Japanese tea ceremony, Sado, and has, in recent years, also been used as a food ingredient. In addition, Sado and food items containing matcha are becoming popular in countries where matcha drinking is a new experience. Therefore, information on the quality of matcha is important for manufacturers, dealers, and consumers in order to produce, select or purchase a product that meets their purpose. To obtain objective information on matcha tastes, we developed a standardized method for evaluating the astringent and umami tastes of matcha using a taste sensor system with standard substances, (-)-epigallocatechin-3-O- gallate (EGCg) for astringent taste and monosodium glutamate (MSG) for umami taste. The precision of these evaluation results was sufficient for its practical use. The evaluation method was applied to commercial matcha samples, and it was revealed that the method has the potential to characterize, in detail, the taste of matcha for different uses.
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Chinese dark teas (CDTs) are post-fermented tea products, which are mainly produced in Southwestern China. The health benefits and chemistry of CDTs are increasing trends in the research field of teas. Deactivated leaves of Camellia sinensis and Camellia assamica are post-fermented under controlled conditions to make CDTs, the quality of which is dependent on the microorganisms like Aspergillus, Penicillium and Eurotium species in postfermentation process. It has been proved that CDTs have anti-obesity effects with respect to decreasing the total serum cholesterol, triglyceride, low density lipoprotein cholesterol (LDL-C) by inhibiting the lipid absorption and biosynthesis. Furthermore, CDTs possess antimicrobial, antioxidative and antimutagenic activities. Besides the health benefits, the safety of CDTs was assessed by acute and chronic toxicity evaluation. Postfermentation structurally changes the original compounds of raw CDTs, significantly decreases the contents of catechins and forms some novel catechins derivatives. In the present paper, we review the postfermentation characteristics, biological activities, chemical constituents and composition analysis of CDTs.
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L-Theanine is an amino acid found in green tea leaf and in its infusion, and is known to control excitement caused by caffeine. It is also known that the oral administration of L-theanine to rats results in a decrease of serotonin and increase of catecholamines in their brain. L-Theanine has been confirmed to be safe in animal experiments. We found recently that oral intake of L-theanine caused a feeling of relaxation among the human volunteers examined. These observations led us to do experiments on the effects of administration of L-theanine on the brain electric waves. Eight female university students were selected as volunteers. Four of them were ranked to be Grade I (the highest anxiety) and the remaining four, Grade V (the lowest anxiety) in an investigation done by the manifest anxiety scale method. A dose of oral administration of 200 mg of L-theanine dissolved in 100 ml of water resulted in the generation of α-electric waves in the occipital and parietal regions of the brains of the subjects. The emission intensity of α-brain waves (integrated as a function of investigation times and area) was significantly greater in the group of Grade I than that of Grade V. These results indicate the possibility for L-theanine to be applied to foods and beverages as a new type of functional food ingredient for its relaxation effect.
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荒茶価格1kg当り560円から12,000円の煎茶61点を集めアミノ酸含量と全窒素量を分析した。上級煎茶と下級煎茶では,グルタミン酸含量にあまり大差がなく,テアニン,グルタミン,アルギニン含量に著しい差が見られた。また,グルタミンの割合が上級煎茶ではグルタミン酸よりも多い傾向があったが,下級煎茶では少なかった。価格と全窒素量は下級煎茶と中級煎茶に相関が認められるが,上級煎茶では認められないため,全窒素量は上級煎茶の品質判定の指標として使用出来ないと考えた。それに対して,全アミノ酸量は,全ての価格帯において相関が認められ,より広い範囲の品質の煎茶の判定に利用できるものと考えられた。また,17種類のアミノ酸の中で最も価格との相関が高かったのはアルギニンとテアニンであった。本研究を進めるにあたって,試料の収集に御協力いただいた静岡県茶商工業協同組合関係各位及び,分析を手伝っていただいた天野いねさんに深く御礼申し上げます。
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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.
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Background: Research has reliably demonstrated that caffeine produces a general increase in physiological arousal in humans, but we previously failed to obtain the expected arousal-based changes in manually quantified event-related potential (ERP) components in response to the stimuli in a simple Go/NoGo task. Methods: A single oral dose of caffeine (250 mg) was used in a randomized double-blind placebo-controlled repeated-measures cross-over study. Adult participants (N=24) abstained from caffeine for 4 hours before each of two sessions, approximately 1 week apart. An equiprobable auditory Go/NoGo task was used, with a random mix of 75 tones at 1,000 Hz and 75 at 1,500 Hz. All tones were 50 ms duration (rise/fall time 5 ms) at 60 dB SPL, with a fixed stimulus-onset asynchrony of 1100 ms. Principal component analysis (a form of factor analysis) was used to quantify orthogonal ERP components. Results: ERP components reflected the different sequential processing of each stimulus type in this paradigm, replicating previous results. Caffeine was associated with a reduction in reaction time and fewer omission errors. The major ERP effects of caffeine were apparent as a slightly enhanced Processing Negativity and larger P3b amplitudes to Go stimuli. There were few effects on components to NoGo stimuli. Conclusions: The results confirm our previous findings that caffeine improves aspects of the differential processing related to response production and task performance, but may be interpreted as supporting the simple amplification of ERP component amplitudes predicted by the general arousal induced by caffeine.
Article
This review discusses the bioavailability of active components of green and black teas--in hot brewed tea, cold tea, and dietary supplements containing tea extracts, based on literature published in 1995-2011. Many publications demonstrate that consumption of tea increases the antioxidant status of a person (between 3.5-76%) and reduces the concentration of oxidative stress biomarkers in biological fluids. In 1-2 hours after tea intake, epigallocatechin gallate (EGCG), epicatechin (EC), and epicatechin gallate (ECG) at a level of 5-150 ng/ml were detected in plasma by HPLC. The results of pharmacokinetics and metabolism of biologically active tea components analyzed within 24 hours in plasma, urine, and feces by HPLC-MS and GC-MS are presented. Dozens of metabolites were identified in urine and plasma—these are methylated, sulfated, and glucuronide conjugates of catechins. Some metabolites were shown to have high antioxidant activity. The role of the small intestine and colon in absorption of catechins was also identified.
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Green Tea: History, Processing Techniques, Principles, Traditions, Features, and Attractions Mahendra P. Kapoor, Theertham P. Rao, Tsutomu Okubo, and Lekh R. Juneja Biochemical and Physicochemical Characteristics of Green Tea Polyphenols Takashi Tanaka, Yosuke Matsuo, and Isao Kouno Metabolism, Bioavailability, and Safety Features of Green Tea Polyphenols Shiming Li and Chi-Tang Ho Green Tea Polyphenols for Cancer Risk Reduction: Preclinical and Epidemiological Studies Naghma Khan, Imtiaz A. Siddiqui, Vaqar M. Adhami, and Hasan Mukhtar Chemopreventive Action of Green Tea Polyphenols (Molecular-Biological Mechanisms) Vijay S. Thakur and Sanjay Gupta Green Tea Prevents Ultraviolet Radiation-Induced Skin Cancer through Rapid Repair of DNA Damage Santosh K. Katiyar Green Tea Polyphenols in Cardiovascular Diseases Hla-Hla Htay, Mahendra P. Kapoor, Theertham P. Rao, Tsutomu Okubo, and Lekh R. Juneja Green Tea Polyphenols in Weight Management (Obesity) and Diabetes Tadashi Sakuma, Hideto Takase, Tadashi Hase, and Ichiro Tokimitsu Green Tea Polyphenols for the Protection of Internal Organs-Focus on Renal Damage Caused by Oxidative Stress Takako Yokozawa, Jeong Sook Noh, Chan Hum Park, and Jong Cheol Park Green Tea Polyphenols Improve Bone and Muscle Quality Olivier M. Dorchies and Urs T. Ruegg Role of Green Tea Polyphenols in Strengthening the Immune System Jack F. Bukowski Green Tea Polyphenols in Allergic Remedies Hirofumi Tachibana Green Tea Polyphenols and Gut Health Theertham P. Rao, Tsutomu Okubo, Mahendra P. Kapoor, and Lekh R. Juneja Green Tea Polyphenols in Oral Care Kazuko Takada and Masatomo Hirasawa Nutrigenomics and Proteomics of Tea Polyphenols Molay K. Roy and Yoshinori Mine Green Tea Polyphenols in Food and Nonfood Applications Mahendra P. Kapoor, Tsutomu Okubo, Theertham P. Rao, and Lekh R. Juneja
Article
A systematic review and meta-analysis was conducted on 11 randomized placebo-controlled human studies of acute effects of tea constituents L-theanine and epigallocatechin gallate, administered alone or in combination with caffeine, on cognitive function and mood. The outcome measures of mood were alertness, calmness, and contentedness, derived from the Bond-Lader scales, and state anxiety, from the State-Trait Anxiety Inventory. Cognitive measures assessed were attentional switch, intersensory attention, and rapid visual information processing. Standardized mean differences between placebo and treatment groups are presented for each study and outcome measure. Meta-analysis using a random-effects model was conducted when data were available for three or more studies. Evidence of moderate effect sizes in favor of combined caffeine and L-theanine in the first 2 hours postdose were found for outcome measures Bond-Lader alertness, attentional switching accuracy, and, to a lesser extent, some unisensory and multisensory attentional outcomes. Moderator analysis of caffeine and L-theanine doses revealed trends toward greater change in effect size for caffeine dose than for L-theanine dose, particularly during the first hour postdose.
Article
l-Theanine (N-ethyl-l-glutamine) is an amino acid uniquely found in green tea. Growing evidence has suggested the possible effects of l-theanine on cognition. Previously, we found that l-theanine attenuates MK-801-induced deficit in prepulse inhibition (PPI) in mice. In this study, we examined the effect of l-theanine in increasing the PPI in healthy humans. The subjects were 14 healthy adults who underwent PPI testing as a measure of sensorimotor gating 90 min after an oral intake of l-theanine (0, 200, 400, or 600 mg). PPI tests were done by examiners who were blind to the dose. The administration of 200 mg of l-theanine and that of 400 mg, but not 600 mg, significantly increased the % PPI compared to the baseline (0 mg). There was no significant relation between the dose of l-theanine and the startle magnitude or the habituation of startle response. The plasma concentrations of l-theanine correlated with the dose of l-theanine. The observed effect with 200-400 mg of l-theanine on PPI suggested that l-theanine at a particular dose range increases sensorimotor gating in humans.
Article
L-Theanine is a unique amino acid almost exclusively found in the leaves of Camellia sinensis (green tea). Suntheanine is the trade name for the proprietary L-Theanine green tea leaf derivative. Scientific and clinical research has investigated the physiological and pharmacological actions of L-Theanine and has confirmed the relaxation and mood enhancement effects and other stress response parameters.
Article
This study showed the relationship between tea leaf age, bud and first two leaves, and shade levels, on the relative concentrations of six major compounds of tea leaf, namely l-theanine, caffeine, and the major tea catechins; (−)-epigallocatechin gallate (EGCG), (−)-epigallocatechin (EGC), (−)-epicatechin (EC), and (−)-epicatechin gallate (ECG), all of which are reported to have positive effects on human health, as well as at the ferric reducing antioxidant power of bud and leaf extracts. The concentration of l-theanine and caffeine decreased as leaf age increased moving from bud to first and then second leaf, while the concentration of the four catechins increased from the bud to first and second leaves. In most cases this increase was generally relatively small but in the case of EGC it was 7 to 10-fold. Certain chemical components of freshly picked, minimally processed and essentially unoxidised tea may potentially be used as markers for age, quality, authenticity and area of growth.
Article
A green tea extract (GTE) was incorporated into biscuit as a source of tea catechins. The stability of tea catechins in the biscuit making process was studied. A method was developed for the separation and quantification of tea catechins in GTE, dough, and biscuit samples using a RP-HPLC system. GTEs at 150, 200, and 300mg per 100g of flour were formulated. The results obtained showed that green tea catechins were relatively stable in dough. The stability of (−)-EGCG and (−)-ECG was determined at an interval of every 2min during baking. Their stability decreased as the baking progressed and increased as the concentration of GTE was increased in the biscuit dough. The stability of (−)-EGCG also increased as pH of the dough was reduced and made less alkaline.
Article
Psychiatrists rarely enquire about caffeine intake when assessing patients. This may lead to a failure to identify caffeine-related problems and offer appropriate interventions. Excessive caffeine ingestion leads to symptoms that overlap with those of many psychiatric disorders. Caffeine is implicated in the exacerbation of anxiety and sleep disorders, and people with eating disorders often misuse it. It antagonises adenosine receptors, which may potentiate dopaminergic activity and exacerbate psychosis. In psychiatric in-patients, caffeine has been found to increase anxiety, hostility and psychotic symptoms. Assessment of caffeine intake should form part of routine psychiatric assessment and should be carried out before prescribing hypnotics. Gradual reduction in intake or gradual substitution with caffeine-free alternatives is probably preferable to abrupt cessation. Decaffeinated beverages should be provided on psychiatric wards.