Article

An intervention study on the effect of matcha tea, in drink and snack bar formats, on mood and cognitive performance

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Abstract

Matcha tea is gaining popularity throughout the world in recent years and is frequently referred to as a mood-and-brain food. Previous research has demonstrated that three constituents present in matcha tea, l-theanine, epigallocatechin gallate (EGCG), and caffeine, affect mood and cognitive performance. However, to date there are no studies assessing the effect of matcha tea itself. The present study investigates these effects by means of a human intervention study administering matcha tea and a matcha containing product. Using a randomized, placebo-controlled, single-blind study, 23 consumers participated in four test sessions. In each session, participants consumed one of the four test products: matcha tea, matcha tea bar (each containing 4 g matcha tea powder), placebo tea, or placebo bar. The assessment was performed at baseline and 60 min post-treatment. The participants performed the Cognitive Drug Research (CDR) test battery. The mood state was measured by means of a Profile of Mood States (POMS). After consuming the matcha products compared to placebo versions, there were mainly significant improvements in tasks measuring basic attention abilities and psychomotor speed in response to stimuli over a defined period of time. In contrast to expectations, the effect was barely present in other tasks of the CDR test battery. The POMS results revealed no significant changes in mood. The influence of the food matrix was demonstrated by the fact that on most cognitive performance measures the drink format outperformed the bar format, particularly in tasks measuring speed of spatial working memory and delayed picture recognition. This study suggests that matcha tea consumed in a realistic dose can induce slight effects on speed of attention and episodic secondary memory to a low degree. Further studies are required to elucidate the influences of the food matrix.

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... Matcha Japanese green tea is a powdered superfood with increasing popularity since it has been related to the improvement of psychic wellbeing as well as physical and cognitive ability. This tea is extracted from a plant called Camellia sinensis [1][2][3][4][5][6][7]. ...
... The most prevalent polyphenols are catechins ( Fig. 1): (-)-epigallocatechin gallate (EGCG), (-)-epigallocatechin (EGC), (-)-epicatechin (EC) and (-)-epicatechin gallate (ECG) [1][2][3][4][5][6][8][9][10][11]. ...
... The NMR analysis through 1 H-DOSY and 1 are the most promising solvents for polyphenols extraction. Such results were corroborated by the extraction of and quantification of polyphenols from matcha green tea. ...
Article
Extracts from plants have considerable significance as bioactive compounds with several pharmacological applications. Polyphenols have attracted the attention as anti-inflammatory and anti-oxidative materials. Nonetheless, the amount of these compounds in the extracts is typically very low. Consequently, green extraction techniques with higher efficiency for phenolic compounds are of paramount importance. Ionic liquids (ILs), which are also known as designer solvents can be used to extract polyphenols, however the search for ideal solvents is mostly done by trial and error. In this work, nuclear magnetic resonance (NMR) is used to study the profile of ILs molecular interactions with model compounds that mimic polyphenols. The ILs that exhibit the strongest molecular interactions were proven to have the highest efficiency when extracting polyphenols from matcha Japanese green tea, known to be extremely rich in these compounds. Both the IL cation and anion have an influence on the solvent behaviour. The best IL solvents for matcha polyphenols were imidazolium derivatives with shorter alkyl side chains and weakly basic anions such as tricyanomethanide, dicyanamide and triflate. Thus, the NMR approach avoids an exhaustive testing and allows the rational selection of the best ILs for the extraction.
... Considering the increased effectiveness of (poly)phenols in counteracting age-related oxidative stress, recent human studies have examined the role of natural (poly)phenols-rich products in the prevention of cognitive decline and maintenance of brain function [15,16]. Several studies have shown that the consumption of (poly)phenols-rich supplementation can benefit cognitive decline in older adults [19][20][21], as well as in young-and middle-aged populations [22][23][24]. Additionally, polyphenols bind to nuclear estrogen receptor α (ERα) and β (ERβ), thus inducing neuroprotective effects. ...
... Fifteen studies [19,23,24,27,28,[47][48][49][50][51][52][53][54][55][56] examining the effects of (poly)phenols-rich supplementation on psychomotor function and/or BDNF met the specific inclusion criteria and were included in the meta-analysis. ...
... The characteristics of each study, as well as the effect of (poly)phenols-rich supplementation on psychomotor function and BDNF are summarized in Tables 2 and 3, respectively. Nine papers [19,23,24,28,[47][48][49][50][51] examined the effect of (poly)phenols-rich supplementation on psychomotor function (e.g., TMTa and RTT). Five studies [27,[52][53][54][55][56] examined the change in serum BDNF following (poly)phenols-rich supplementation. ...
Article
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Background: Recent anti-aging interventions have shown contradictory impacts of (poly)phenols regarding the prevention of cognitive decline and maintenance of brain function. These discrepancies have been linked to between-study differences in supplementation protocols. This subgroup analysis and meta-regression aimed to (i) examine differential effects of moderator variables related to participant characteristics and supplementation protocols and (ii) identify practical recommendations to design effective (poly)phenol supplementation protocols for future anti-aging interventions. Methods: Multiple electronic databases (Web of Science; PubMed) searched for relevant intervention published from inception to July 2019. Using the PICOS criteria, a total of 4303 records were screened. Only high-quality studies (n = 15) were included in the final analyses. Random-effects meta-analysis was used, and we calculated standard differences in means (SDM), effect size (ES), and 95% confidence intervals (CI) for two sufficiently comparable items (i.e., psychomotor function and brain-derived neurotrophic factor (BDNF)). When significant heterogeneity was computed (I2 > 50%), a subgroup and meta-regression analysis were performed to examine the moderation effects of participant characteristics and supplementation protocols. Results: The reviewed studies support the beneficial effect of (poly)phenols-rich supplementation on psychomotor functions (ES = -0.677, p = 0.001) and brain plasticity (ES = 1.168, p = 0.028). Subgroup analysis revealed higher beneficial impacts of (poly)phenols (i) in younger populations compared to older (SDM = -0.89 vs. -0.47 for psychomotor performance, and 2.41 vs. 0.07 for BDNF, respectively), (ii) following an acute compared to chronic supplementation (SDM = -1.02 vs. -0.43 for psychomotor performance), and (iii) using a phenolic compound with medium compared to low bioavailability rates (SDM = -0.76 vs. -0.68 for psychomotor performance and 3.57 vs. 0.07 for DBNF, respectively). Meta-regressions revealed greater improvement in BDNF levels with lower percentages of female participants (Q = 40.15, df = 6, p < 0.001) and a skewed scatter plot toward a greater impact using higher (poly)phenols doses. Conclusion: This review suggests that age group, gender, the used phenolic compounds, their human bioavailability rate, and the supplementation dose as the primary moderator variables relating to the beneficial effects of (poly)phenol consumption on cognitive and brain function in humans. Therefore, it seems more advantageous to start anti-aging (poly)phenol interventions in adults earlier in life using medium (≈500 mg) to high doses (≈1000 mg) of phenolic compounds, with at least medium bioavailability rate (≥9%).
... As a result, very little is known about the effect of polyphenol interventions on brain-related aging processes in healthy young humans. Additionally, the few available studies in this field demonstrate controversial findings; some of them indicate improved brain function following acute and/or chronic ingestion of polyphenol-rich supplementation [36][37][38][39][40], while other findings fail to prove beneficial effects on cognitive function and brain structures of young and middle-aged adults [41][42][43]. ...
... Sixteen studies [36][37][38][39][40][41][42][43][45][46][47][48][49][50][51][52] examining the effects of (poly)phenol-rich supplementation on cognitive functions and/or brain related parameters were considered to meet the specific inclusion criteria and were included in the current SR. ...
... Seven papers [36,38,[45][46][47][48]50] examined the effect of rich-(poly)phenol supplementation on cognitive function (e.g., reaction time, memory, learning abilities, attention, and executive functioning), as well as a variety of brain-related parameters (e.g., neuroplasticity, cerebral hemodynamics and blood flow). Six studies [37,[39][40][41]49,51] only examined the effect of rich-(poly)phenol supplementation on cognitive function. Three studies [42,43,52] only examined the change in serum BDNF [42,43] and stroke volume (SV) [52] following rich-(poly)phenol supplementation. ...
Article
Full-text available
Context: Affecting older and even some younger adults, neurodegenerative disease represents a global public health concern and has been identified as a research priority. To date, most anti-aging interventions have examined older adults, but little is known about the effects of polyphenol interventions on brain-related aging processes in healthy young and middle-aged adults. Objective: This systematic review and meta-analysis aimed to evaluate the acute and chronic effects of (poly)phenol-rich diet supplementation on cognitive function and brain health in young and middle-aged adults. In July 2019, two electronic databases (PubMed and Web of Science) were used to search for relevant trials examining the effect of acute or chronic (poly)phenol-rich supplementation on cognitive function and neuroprotective measures in young and middle-aged adults (<60 years old). A total of 4303 records were screened by two researchers using the PICOS criteria. Fifteen high quality (mean PEDro score = 8.8 ± 0.58) trials with 401 total participants were included in the final analyses. Information on treatment, study design, characteristics of participants, outcomes and used tools were extracted following PRISMA guidelines. When items were shown to be sufficiently comparable, a random-effects meta-analysis was used to pool estimates across studies. Effect size (ES) and its 95% confidence interval (CI) was calculated. The meta-analysis indicated that (poly)phenol supplementation significantly increased brain-derived neurotrophic factor (ES = 3.259, p = 0.033), which was accompanied by higher performance in serial (7s) subtraction (ES = 1.467, p = 0.001) and decreases in simple reaction time (ES = -0.926, p = 0.015) and mental fatigue (ES = -3.521 p = 0.010). Data related to cognitive function were skewed towards an effect from acute compared to chronic polyphenol intervention; data related to BDNF were skewed toward an effect from higher bioavailability phenolic components. Conclusion: This meta-analysis provides promising findings regarding the usefulness of polyphenol-rich intervention as an inexpensive approach for enhancing circulation of pro-cognitive neurotrophic factors. These beneficial effects appear to depend on the supplementation protocols. An early acute and/or chronic application of low- to high-dose phenolic components with high bioavailability rates (≥30%) at a younger age appear to provide more promising effects.
... For consuming matcha powder, the whole powder is mixed with hot water so that the whole content of leaves are consumed not only the extract Weiss & Anderton, 2003). The chemical composition of the matcha powder is reported to be different of that of green tea due to various factors such as cultivation conditions, processing and also the consumption of whole powder not the extract and most of these studies report that the content of catechins, caffeine and theanine is higher in tea leaves cultivated for preparing matcha as compared to those for normal tea (Dietz, Dekker, & Piqueras-Fiszman, 2017;Komes, Horžić, Belščak, Ganić, & Vulić, 2010;Kurauchi et al., 2019;Weiss & Anderton, 2003). In recent years, there is constant growth in the market and consumption of matcha not only as a drink but as a functional component in other beverages, snacks, chocolates, ice creams and many others both in Japan and overseas (Kochman, Jakubczyk, Antoniewicz, Mruk, & Janda, 2020;Kurauchi et al., 2019). ...
... Bioactive components present in tea leaves such as catechins, phenolic acids, amino acids, vitamins and caffeine are reported to be beneficial for human health having various biological activities such as chemopreventive, antioxidant and mood enhancing activities (de Souza, (Bonuccelli, Sotgia, & Lisanti, 2018;Dietz et al., 2017;Koláčková et al., 2020;Kurauchi et al., 2019;Pervin et al., 2018;Weiss & Anderton, 2003). Matcha has been first identified and employed to treat diverse human ailments in Japan, in the form of matcha green tea. ...
... Besides its stress reducing ability, matcha was also evaluated for the improvement of cognitive function. Presence of active ingredient such as epigallocatechin gallate, theanine, and caffeine was responsible for the cognition improvement functions of matcha (Dietz et al., 2017). A recent study reported that consumption of matcha tea partially improved the cognitive performance of matcha tea in human participants, however, matcha tea consumption significantly improved the memory and task measuring dimension of attention. ...
Article
Background The interest in the plant-derived healthy foods, nutraceuticals, functional foods and food supplements is increasing in recent times as potential agents in maintenance of health and the prevention and treatment of diseases. Matcha tea powder is obtained from the leaves of tea plant (Camellia sinensis (L.) Kuntze) grown under specific condition using about 90% shade. As compared to green tea, a hot water extract of tea leaves, matcha is consumed as a whole powder of leaves. Matcha powder is reported to have higher content of some bioactive components such as catechins, theanine and caffeine. In recent years, there is an increased market demand and consumption of matcha as a drink and as a component in various beverages, snacks and other food products. Scope and approach In this review, the available scientific information of the chemical constituents and their analysis and biological activities are critically analyzed. These results may help to understand current status of research on matcha and the gaps which help to guide future research related to evidence based product formulations. Key findings and conclusions Various studies have reported the difference in bioactive compounds in matcha as compared to green tea and other tea formulations. The content and composition were mostly affected by the cultivation and processing techniques. Analysis of marketed samples in various countries have shown the variable content of the bioactive compounds. Thus, there is a need for proper standardization for maintaining the quality. Matcha as a whole, its extract and compounds have shown promising biological activities in in vitro and animal studies. However, comparatively only a few clinical studies are performed, which need future attention. There should also be detailed study regarding matcha-containing foods’ formulation.
... Outcomes of these studies, however, are mixed. While some studies showed positive acute effects of polyphenols, particularly in tasks that measure speed of attention (Scholey et al., 2010;Field et al., 2011;Watson et al., 2015;Dietz et al., 2017), others failed to show such beneficial effects Bondonno et al., 2014;Wightman et al., 2014). Furthermore, given the heterogeneity in study quality, design, and polyphenol type and dosage, it is challenging to reach a definite conclusion whether (i) acute polyphenol intake improves cognition when compared to a matching placebo/control, and (ii) whether this improvement is specific to a type of polyphenol, age group, and/or cognitive domain only. ...
... In choice RT, digit vigilance and RVIP tasks, we used both accuracy (% correct) and speed (ms) data. Short descriptions of simple RT (Wightman et al., 2012;Bondonno et al., 2014;Massee et al., 2015;Dietz et al., 2017;Haskell-Ramsay et al., 2017, 2018aKennedy et al., 2017;Watson et al., 2019), choice RT (Field et al., 2011;Wightman et al., 2012;Bondonno et al., 2014;Massee et al., 2015;Dietz et al., 2017;Haskell-Ramsay et al., 2017, 2018aKennedy et al., 2017;Watson et al., 2019), digit vigilance (Bondonno et al., 2014;Watson et al., 2015Watson et al., , 2019Keane et al., 2016;Dietz et al., 2017;Haskell-Ramsay et al., 2017, 2018aKennedy et al., 2017), and RVIP (Kennedy et al., , 2020Scholey et al., 2010;Cropley et al., 2012;Wightman et al., 2012Wightman et al., , 2014Wightman et al., , 2018Massee et al., 2015;Watson et al., 2015;Keane et al., 2016;Haskell-Ramsay et al., 2018a;Philip et al., 2019) tasks are available elsewhere. ...
... In choice RT, digit vigilance and RVIP tasks, we used both accuracy (% correct) and speed (ms) data. Short descriptions of simple RT (Wightman et al., 2012;Bondonno et al., 2014;Massee et al., 2015;Dietz et al., 2017;Haskell-Ramsay et al., 2017, 2018aKennedy et al., 2017;Watson et al., 2019), choice RT (Field et al., 2011;Wightman et al., 2012;Bondonno et al., 2014;Massee et al., 2015;Dietz et al., 2017;Haskell-Ramsay et al., 2017, 2018aKennedy et al., 2017;Watson et al., 2019), digit vigilance (Bondonno et al., 2014;Watson et al., 2015Watson et al., , 2019Keane et al., 2016;Dietz et al., 2017;Haskell-Ramsay et al., 2017, 2018aKennedy et al., 2017), and RVIP (Kennedy et al., , 2020Scholey et al., 2010;Cropley et al., 2012;Wightman et al., 2012Wightman et al., , 2014Wightman et al., , 2018Massee et al., 2015;Watson et al., 2015;Keane et al., 2016;Haskell-Ramsay et al., 2018a;Philip et al., 2019) tasks are available elsewhere. ...
Article
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Background: The effects of polyphenols on cognitive functions have been extensively studied. Due to the large heterogeneity in the study designs, however, it is often difficult to interpret their efficacy. To address this issue, we conducted a systematic review and meta-analyses to examine whether acute polyphenol intake may have a beneficial effect on cognition and specifically on the accuracy and speed of attention. Methods: PubMed and Scopus databases were systematically searched for studies published up to end of August 2020 following PRISMA guidelines (PROSPERO registration number: CRD42021232109). Only placebo-controlled human intervention trials that assessed acute effects of polyphenols on accuracy and speed of attention were included in the meta-analyses. When cognitive tasks were repeated over time, pooled means and standard deviations for intervention and placebo over repetitions separately for each task for both speed and accuracy were calculated. We also conducted separate analyses focusing only on the last repetition. Furthermore, confounding effects of age and source of polyphenols were also considered. Results: Eighteen studies met the inclusion criteria. The pooled analysis of last task repetitions showed that the acute consumption of polyphenols improved rapid visual information processing speed in young participants ( SMD = 0.26; 95% CI = [0.03–0.50]; I ² = 0%; p = 0.02; k = 5). All other analyses did not reach significance. Conclusion: The results of the current study indicate that acute polyphenol consumption might improve speed in rapid visual information processing task, a higher order task with elements of vigilance, working memory, and executive function, in young participants; however, as the current literature is inconsistent and limited, further acute intervention studies are warranted to achieve more conclusive results.
... Green tea powder (GTP) is very well-received in the food industry because of its comfortable color, complete bioactive components of tea leaves, and excellent characteristics for food processing [1], such as smoothies and baking [2][3][4][5]. GTP contains higher [1][2][3][4][5][6][7][8][9] contents of phenolic acids, theanine, and chlorophylls than other green tea varieties [6]. Moreover, GTP as a powdered form makes it more accessible to be applied in various foods, such as noodles, biscuits, candy, and pastries [7][8][9]. ...
... Green tea powder (GTP) is very well-received in the food industry because of its comfortable color, complete bioactive components of tea leaves, and excellent characteristics for food processing [1], such as smoothies and baking [2][3][4][5]. GTP contains higher [1][2][3][4][5][6][7][8][9] contents of phenolic acids, theanine, and chlorophylls than other green tea varieties [6]. Moreover, GTP as a powdered form makes it more accessible to be applied in various foods, such as noodles, biscuits, candy, and pastries [7][8][9]. ...
Article
Full-text available
Microwave radiation is one of the main heating methods for food processing, especially affecting the color quality of colorful foods. This work presents the effect of microwave radiation on the green color loss of green tea powder (GTP) by the color description (L*, a*, b*, and Ha of green tea powder, L*:whiteness/darkness, a*: redness/greenness, and b*: yellowness/blueness; Ha derived from Hunter a and b could visually describe the color space) of the Hunter color system. First, the L*, a*, and b* were determined from the GTP samples treated with various microwave powers with the change of time to investigate the kinetic of color loss. Then, the L*, a*, and b*and temperature of GTP samples with serious thickness treated with constant microwave power (700 W) for a different time were determined to study the effect of sample thickness on the color loss. Finally, the chemicals that contributed to color change in the GTP samples treated with mild, moderate, and severe radiation were analyzed. The results showed that L*, |a*| (|a*|was the absolute value of a*), b*, and Ha decreased with the power increase in microwave radiation, and their changes conformed to the first-order kinetics. The activation energies (Ea) of different thickness GTP for change of L*, a*, b*, and Ha values could be predicted with the fitting models, and Ea for 20 mm-thick GTP were approximately 1/5, 1/8, 1/8, and 1/13 of those for 4 mm-thick GTP. The color loss was mainly caused by the Mg2+ loss of chlorophylls and the formation of derivates under mild radiation, the degradation of chlorophylls and the formation of theaflavin from catechins under moderate radiation, and the degradation of chlorophylls and their derivates accompanied by Maillard reaction between reducing sugar and amino acids under severe radiation. The results indicate that sample thickness and radiation time are two key parameters to keeping the color of GTP in food processing and microwave pasteurization.
... A large number of studies have confirmed that tea is beneficial to human health and has certain medical effects on modern diseases such as cardiovascular and cerebrovascular diseases, cerebrovascular diseases and cancer. Dietz et al. believe that tea can affect mood [1]. Spittler et al. ...
... The number of hidden layer nodes is as follows: a n m h + + = (1) Among them, h is the number of hidden layer nodes, m is the number of input layer nodes, n is the number of output layer nodes, and a is an adjustment constant between 1 and 10. ...
Article
Tea can help to regulate the mood of human. Based on the influence of tea on people's mood and attention, this study explored the tea concentration when the mood and attention of drinkers are in the best state, and established the best concentration model of tea. Using sampling experiment method to collect objective data, which are then combined with questionnaire survey method to collect subjective data, using the results to establish a neural network algorithm model to test the accuracy of the neural network algorithm model. Experiments show that the correlation coefficient of the output value of the BP neural network model constructed in this study is basically consistent with the actual prediction result. After obtaining data such as age, gender, frequency of tea drinking, and tea drinking concentration of tea drinkers, the constructed back propagation (BP) neural network model can accurately predict the mental state score of tea drinkers. The research will provide certain data support and theoretical basis for the follow-up development of the tea industry. Follow-up work needs to be performed in order to further adjust the scope and accuracy of the control model. Then, a more complete and accurate advanced BP neural network model can be established for different types of tea and other parameters.
... Observations from in-vivo studies in humans on the effects of Matcha are limited (e.g. Dietz et al. 2017;Willems et al. 2018). Dietz et al. (2017) reported acute effects of Matcha green tea powder (4 grams) on specific attentional tasks. ...
... Dietz et al. 2017;Willems et al. 2018). Dietz et al. (2017) reported acute effects of Matcha green tea powder (4 grams) on specific attentional tasks. As far as we know, Willems et al. (2018) is the only study that examined the effects of Matcha consumption and exercise-induced metabolic responses. ...
Article
Artificial green tea extracts may enhance exercise-induced fat oxidation. Natural Matcha green tea consumption involves the ingestion of the powdered green tea leaves. We examined the effects of three weeks daily intake of Matcha green tea powder on substrate oxidation during moderate-intensity exercise in females. Females with a regular menstrual cycle (n = 12, age: 28 ± 10 yr, body mass: 69 ± 17 kg, height: 163 ± 6 cm) volunteered to complete an incremental walking test to determine the individual moderate exercise intensity (four metabolic equivalent) for the subsequent 30-min treadmill walk. The study had a randomized placebo-controlled cross-over design with participants tested between day 9 and 11 of the menstrual cycle (follicular phase). Participants consumed 3x1 gram capsules of Matcha premium grade, (OMGTea Ltd, UK) per day for three weeks, with the final dose (1 gram) two hours before the 30-min walk (walking speed: 5.8 ± 0.4 km·h-1). Matcha had no effect on physiological responses (e.g. heart rate, placebo: 127 ± 14; Matcha: 124 ± 14 beats·min-1, p = 0.154), but resulted in lower respiratory exchange ratio (placebo: 0.872 ± 0.040; Matcha: 0.839 ± 0.035) (p = 0.033), higher fat oxidation by 35 ± 47% (placebo: 0.21 ± 0.08; Matcha: 0.26 ± 0.06 g·min-1) (p = 0.034), and lower carbohydrate oxidation (placebo: 0.75 ± 0.21; Matcha: 0.60 ± 0.18 g·min-1) (p = 0.048) during the 30-min moderate-intensity walk. Energy expenditure was similar for both conditions. There was no significant correlation between body fat % and the absolute or relative change in Matcha-induced fat oxidation during exercise. Continuous intake of Matcha green tea effects exercise-induced metabolic responses by enhancing fat oxidation during moderate-intensity exercise in adult females, seemingly independent of body composition.
... In another study, 23 subjects were randomized to receive either matcha tea, a matcha snack bar (each containing 4 g matcha powder with 67 mg theanine and 136 mg caffeine), placebo tea, or placebo snack bar, while performing cognitive tasks at both baseline and post-consumption [96]. The treatments were offered for 4 days, and each day cognitive function was assessed before and after consumption. ...
... The effect on cognition of xanthines, antioxidants found in foods such as coffee, tea, and chocolate, has also received considerable research interest. Various studies suggest that xanthines such as caffeine may improve cognition, including alertness, accuracy, and reaction time [90][91][92][93][94][95][96][97][98]. Thus, several plant extracts or components have shown promise in improving cognitive function among healthy adults, although the evidence stems largely from small trials with various methodological differences and limitations. ...
Article
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Background and aim: Brain health is becoming more important to the average person as the number of people with cognitive impairments, such as Alzheimer's disease (AD), is rising significantly. The current Food and Drug Administration-approved pharmacotherapeutics for dementia neither cure nor halt cognitive decline; they just delay the worsening cognitive impairment. This narrative review summarizes the effects of nutrients and phytonutrients on cognitive function. Methods: A comprehensive literature search of PubMed was performed to find clinical trials in humans that assessed the effects of nutrients and phytonutrients on cognitive function published in English between 2000 and 2021. Six independent reviewers evaluated the articles for inclusion in this review. Results: Ninety-six articles were summarized in this narrative review. In total 21 categories of nutrients and phytonutrients were included, i.e., α-lipoic acid, Bacopa monnieri, B vitamins, cholinergic precursors, vitamin D, vitamin E, Ginkgo biloba, ginseng, lion's mane mushroom, N-acetyl cysteine, omega-3 fatty acids, aloe polysaccharides, Rhodiola rosea, rosemary, saffron, tart cherries, turmeric, wild yam, Withania somnifera, xanthines, and zinc. Particular noteworthy effects on cognition included memory, recollection, attention, intelligence, vocabulary, recognition, response inhibition, arousal, performance enhancement, planning, creative thinking, reaction time, vigilance, task switching, orientation to time, place, and person, reading, writing, comprehension, accuracy, learning, information processing speed, executive function, mental flexibility, daily functioning, decrease in mental fatigue, and freedom from distractibility. Some nutrients and phytonutrients also improved mood and contentedness and reduced anxiety and the need for caregiving. These effects are not completely consistent or ubiquitous across all patient populations or health statuses. Adverse effects were minimal or nonexistent. Conclusion: Due to the growing population of people with cognitive impairment and the lack of effective pharmacotherapeutics, it is prudent for those afflicted or their caregivers to find alternative treatments. Our narrative review shows that many of these nutrients and phytonutrients may be promising for treating some aspects of cognitive impairment, especially for people afflicted with AD. Relevance for patients: As demonstrated in a number of clinical trials, healthy adults and patients with various health challenges (e.g., AD, mild cognitive impairment, multiple sclerosis, and Parkinson's disease) exhibiting a wide range of severity in cognitive defects would be best served to consider multiple nutrients and phytonutrients to improve aspects of their cognitive function.
... 24 The water is first heated to boiling (100 C) to destroy any microbes, then the temperature is lowered to 80 C and the tea is added to ensure the preservation of vitamins and amino acids in the leaves. 25 The time when the water reached the temperature of 80 C was applied at all times of brewing green tea. Green tea was brewed with the help of a center staff member, and the cups were standardized so that all the elderly drank the same volume and concentration of tea. ...
... Zhang et al 24 and Dietz et al 25 suggested dietary restrictions for the participants to avoid distortion of the obtained results. These restrictions include nonconsumption of foods and beverages containing alcohol and herbal supplements during the study and also nonconsumption of foods and beverages containing caffeine from 4 hours before the measurement of variables. ...
Article
The world’s older population continues to grow at an unprecedented rate. Iran is 1 of the countries where the aging population is higher than the global average. Depression is 1 of the most common issues in older adults that can be managed by nonpharmacologic interventions such as the consumption of green tea. The aim of this study was to determine the effect of green tea consumption on depression in the elderly people. In this quasi-experimental study, 76 elderly people who were residents in a nursing home and met the inclusion criteria were selected through simple random sampling. Then, green tea in 3-g tea bags was brewed in 80°C water and half an hour after breakfast and lunch was given to the participants in a 5-week protocol. One day after the last time of brewing green tea, participants were assessed with a standard depression questionnaire. The obtained data were analyzed using SPSS Version 19 software (IBM Corp, Armonk, NY). The descriptive statistics and Wilcoxon statistical test analysis were also conducted at a significant level of P < .05. Based on the findings, the mean score of the participants’ depression level decreased by 2.5 points after the intervention, which is statistically significant at a 99.9% confidence interval (P = .001). The findings also suggest that the severe depression decreased from 23.6% to 11.1%, moderate depression decreased from 45.8% to 26.4%, and mild depression increased from 30.6% to 45.8%; only severe and moderate depression cases were reduced (P = . 001). The findings of the present study reveal that regular consumption of green tea can lead to a considerable reduction of depression in the elderly people. Accordingly, the consumption of this tea in the elderly people’s diet is recommended, especially those who are resident in the care centers.
... The action of orally administered caffeine regarding the NCD of attention has been extensively examined in humans, as detailed in this section. Caffeine has been experimentally administered to humans in a wide variety of formulations, including pills (Wilhelmus et al. 2017), infusions or brewed drinks (Christopher, Sutherland, and Smith 2005;Dietz, Dekker, and Piqueras-Fiszman 2017), foods (i.e., matcha tea as an ingredient in food preparations (Dietz, Dekker, and Piqueras-Fiszman 2017)), guarana White et al. 2017)), or in conjunction with sugars (Rao, Hu, and Nobre 2005;Scholey et al. 2014;Scholey and Kennedy 2004;Ullrich et al. 2015) or taurine (Alford, Cox, and Wescott 2001;Scholey and Kennedy 2004;Seidl et al. 2000;Wesnes et al. 2017), generally in energizing drinks, as well as with L-threonine (Haskell et al. 2008;Haskell et al. 2007;Kelly et al. 2008), theacrine from Camellia kucha (Hung T. Chang) (Kuhman, Joyner, and Bloomer 2015) or Panax ginseng C.A. Mey ) among others. A systematic review and meta-analysis that included 11 randomized placebo-controlled human studies concluded that there was a synergistic effect on attentional switching accuracy when caffeine and L-theanine were combined within a 2-hour timespan (Camfield et al. 2014). ...
... The action of orally administered caffeine regarding the NCD of attention has been extensively examined in humans, as detailed in this section. Caffeine has been experimentally administered to humans in a wide variety of formulations, including pills (Wilhelmus et al. 2017), infusions or brewed drinks (Christopher, Sutherland, and Smith 2005;Dietz, Dekker, and Piqueras-Fiszman 2017), foods (i.e., matcha tea as an ingredient in food preparations (Dietz, Dekker, and Piqueras-Fiszman 2017)), guarana White et al. 2017)), or in conjunction with sugars (Rao, Hu, and Nobre 2005;Scholey et al. 2014;Scholey and Kennedy 2004;Ullrich et al. 2015) or taurine (Alford, Cox, and Wescott 2001;Scholey and Kennedy 2004;Seidl et al. 2000;Wesnes et al. 2017), generally in energizing drinks, as well as with L-threonine (Haskell et al. 2008;Haskell et al. 2007;Kelly et al. 2008), theacrine from Camellia kucha (Hung T. Chang) (Kuhman, Joyner, and Bloomer 2015) or Panax ginseng C.A. Mey ) among others. A systematic review and meta-analysis that included 11 randomized placebo-controlled human studies concluded that there was a synergistic effect on attentional switching accuracy when caffeine and L-theanine were combined within a 2-hour timespan (Camfield et al. 2014). ...
Article
Substances with modulatory capabilities on certain aspects of human cognition have been revered as nootropics from the dawn of time. The plant kingdom provides most of the currently available nootropics of natural origin. Here, in this systematic review, we aim to provide state-of-the-art information regarding proven and unproven effects of plant-derived nootropics (PDNs) on human cognition in conditions of health and disease. Six independent searches, one for each neurocognitive domain (NCD), were performed in parallel using three independent scientific library databases: PubMed, Cochrane and Scopus. Only scientific studies and systematic reviews with humans published between January 2000 and November 2021 were reviewed, and 256 papers were included. Ginkgo biloba was the most relevant nootropic regarding perceptual and motor functions. Bacopa monnieri improves language, learning and memory. Withania somnifera (Ashwagandha) modulates anxiety and social-related cognitions. Caffeine enhances attention and executive functions. Together, the results from the compiled studies highlight the nootropic effects and the inconsistencies regarding PDNs that require further research.
... Green tea (Camellia sinensis) is commercially available in the market in three forms: Loose leaf, bagged and powdered (matcha) [6]. Matcha is generally consumed in Japan as a beverage that has high anti-oxidants such as flavonoids [7]. Many natural foods and beverages that are commonly consumed by people in a region, such as honey in the tropical regions, olive oil, virgin coconut oil and others have been partially known to have antibacterial effects especially in the oral cavity [8]. ...
... 3 It contains a variety of essential trace elements and nutrients possessing high nutritional value. 4 It can maintain the original natural green and has strong surface adsorption and affinity, thus it can be easily digested and absorbed by the stomach with antifatigue, antitumor, antioxidant, blood pressure-decreasing and radiation protection qualities. 5 The different types of raw materials, picking time and shading time in the making of green tea involve a series of biochemical reactions based on tea polyphenols and amino acids that lead to significant changes in internal composition. ...
Article
BACKGROUND The study reports a portable near infrared (NIR) spectroscopy system coupled chemometric algorithms for predicting tea polyphenols and amino acids in order to index matcha tea quality. RESULTS The spectral data was preprocessed by standard normal variate (SNV), mean center (MC) and first‐order derivative (1stD). The data were then subjected to full spectral PLS and four variables selection algorithms such as random frog partial least square (RF‐PLS), synergy interval partial least square (Si‐PLS), genetic algorithm‐partial least square (GA‐PLS) and competitive adaptive reweighted sampling partial least square (CARS‐PLS). RF‐PLS was established and identified as the optimum model based on the values of the correlation coefficients of prediction (RP), root mean square error of prediction (RMSEP) and residual predictive deviation (RPD), which were 0.8625, 0.82%, 2.13 and 0.9662, 0.14%, 3.83 respectively for tea polyphenols and amino acids. The content range of tea polyphenols and amino acids in matcha tea samples was 8.51‐14.58% and 2.10‐3.75%, respectively. The quality of matcha tea was successfully classified with an accuracy rate of 83.33% as qualified, unqualified and excellent grades. CONCLUSION The proposed method can be used as a rapid, accurate and non‐destructive platform to classify various matcha tea samples based on the ratio of tea polyphenols to amino acids. This article is protected by copyright. All rights reserved.
... Due to the C3 nature of the plants however, shading from intense sunlight could make it a suitable plant in the overcast weather of Ireland (Nair, 2010). According to Dietz et al.,2017 "Three to four weeks before the harvest, the plants are 90% shaded, which enhances the tea quality by increasing the maturing period". An increase in carbon dioxide from 380 ppm to 600-700 ppm in the atmosphere in 2100 may be beneficial for growth in Ireland due to the warmer temperatures from the greenhouse effect and increased precipitation Drought however will cause a decrease in yield of up to 33% (Cheruiyot et al. 2010). ...
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This experiment investigated the growth of Camellia Sinensis under in-vitro conditions. Nodes, leaves, stems, shoot tips were collected from the glasshouse and were grown on a solid media. This was done by testing various explants on various amounts of 6-Benzylaminopurine(BAP) and auxin 2,4-Dichlorophenoxyacetic acid(2,4-D). Various sterilisation protocols were tested. The optimum callus growth was seen on nodal segments placed in ethanol for 3 minutes and then soaked in Domestos TM Bleach for 60 minutes with 2-3 drops of tween 20 followed by rinsing with distilled water and then placed on medium with 4 mg/l BAP and 4mg/l of NAA. Callus growth observed on leaves and nodal segments. 21 days later the non-contaminated callus was subcultured on fresh medium with 3mg of BAP and 0.5mg of GA3 to induced shoot growth. Contamination was consistently present in most leaf and stem explants under various sterilisation protocol and media. There was also a high rate of browning. Some shoot elongation as well as callus was also visible on leaves when subcultured on GA3. Low survival rate was observed with fungal and bacterial contamination being the main problem affecting the culture of Camellia Sinensis. In this study a literature review was conducted on the uses and characteristics of Camellia Sinensis.
... At the meta-data level, tea intake has not been strongly associated with improved affective state, with the exception of improved alertness [213,214], likely resulting from synergistic effects of caffeine and L-theanine [215]. One randomized, placebo-controlled, single-blind study (n = 23) conducted in four sessions found that 4 g of matcha tea powder induced no significant changes in mood, but did induce significant improvements in attention tasks and psychomotor speed in response to stimuli [216]. In two studies measuring the effect of EGCG on affective state, one reported no mood effect in response to 270 mg EGCG tablets [217], and another found 300 mg EGCG supplementation to significantly increase self-rated calmness (p = 0.04) and reduced stress (p = 0.017) measured as change-from-baseline [218]. ...
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This article is a comprehensive review of the literature pertaining to the antidepressant effects and mechanisms of regular tea consumption. Meta-data supplemented with recent observational studies were first analyzed to assess the association between tea consumption and depression risk. The literature reported risk ratios (RR) were 0.69 with 95% confidence intervals of 0.62–0.77. Next, we thoroughly reviewed human trials, mouse models, and in vitro experiments to determine the predominant mechanisms underlying the observed linear relationship between tea consumption and reduced risk of depression. Current theories on the neurobiology of depression were utilized to map tea-mediated mechanisms of antidepressant activity onto an integrated framework of depression pathology. The major nodes within the network framework of depression included hypothalamic-pituitary-adrenal (HPA) axis hyperactivity, inflammation, weakened monoaminergic systems, reduced neurogenesis/neuroplasticity, and poor microbiome diversity affecting the gut–brain axis. We detailed how each node has subsystems within them, including signaling pathways, specific target proteins, or transporters that interface with compounds in tea, mediating their antidepressant effects. A major pathway was found to be the ERK/CREB/BDNF signaling pathway, up-regulated by a number of compounds in tea including teasaponin, L-theanine, EGCG and combinations of tea catechins and their metabolites. Black tea theaflavins and EGCG are potent anti-inflammatory agents via down-regulation of NF-κB signaling. Multiple compounds in tea are effective modulators of dopaminergic activity and the gut–brain axis. Taken together, our findings show that constituents found in all major tea types, predominantly L-theanine, polyphenols and polyphenol metabolites, are capable of functioning through multiple pathways simultaneously to collectively reduce the risk of depression.
... Research on the use of matcha green tea powder in food products are taken to a small extent (diEtz et al. 2017). The technology of extruded products production allows the use of various raw materials that have a positive effect not only on nutritional and sensory elements of products, but also can cause significant and not always beneficial changes in their physicochemical properties (pAStOR-CAVAdA et al. 2011). ...
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The aim of this research was to assess the possibility of using matcha green tea powder in the production of corn puffs, as well as to determine its impact on the quality features of the extrudates. The research material consisted of corn puffs (without and with 1%, 3% and 5% addition of matcha green tea powder) obtained by the extrusion process under laboratory conditions. The aim of the research was realized by examining the mass, geometrical characteristics, hardness parameters using the Universal Testing Machine (Instron) and color using Digital Image Analysis of the extrudates. In addition, moisture and water absorption capacity of finished products and raw materials were determined. It was shown that matcha green tea powder causes a significant extension of the products (with simultaneous effect on reducing the width), the lower share of the additive also affects the increase of their weight and volume. Matcha green tea powder changes the strength characteristics of corn puffs, primarily increases their hardness, which consequently leads to deterioration or even disappearance (5% addition) of elasticity and flexibility. On the basis of the obtained results, it can be concluded that 1–3% addition of matcha green tea powder to corn puffs not influence significantly on the quality features, and may be use in extrusion process to obtain a product with an attractive green color and probably a higher nutritional value.
... This may cause confusing results. For example, the effect of matcha tea on mood and cognitive performance has been examined [33]. The mood state measured by a Profile of Mood State (POMS) was not significantly changed by the ingestion of four grams of matcha tea. ...
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Theanine, a major amino acid in green tea, exhibits a stress-reducing effect in mice and humans. Matcha, which is essentially theanine-rich powdered green tea, is abundant in caffeine. Caffeine has a strong antagonistic effect against theanine. The stress-reducing effect of matcha was examined with an animal experiment and a clinical trial. The stress-reducing effect of matcha marketed in Japan and abroad was assessed based on its composition. The stress-reducing effect of matcha in mice was evaluated as suppressed adrenal hypertrophy using territorially-based loaded stress. High contents of theanine and arginine in matcha exhibited a high stress-reducing effect. However, an effective stress-reducing outcome was only possible when the molar ratio of caffeine and epigallocatechin gallate (EGCG) to theanine and arginine was less than two. Participants (n = 39) consumed test-matcha, which was expected to have a stress-reducing effect, or placebo-matcha, where no effect was expected. Anxiety, a reaction to stress, was significantly lower in the test-matcha group than in the placebo group. To predict mental function of each matcha, both the quantity of theanine and the ratios of caffeine, EGCG, and arginine against theanine need to be verified.
... Matcha is finely ground powder of green tea leaves with special planting and processing. Particularity is that the green tea plants for matcha should under shaded conditions for more than twenty days prior to harvest (Dietz et al., 2017). This is believed to increase chlorophyll content and retain the antioxidants of the leaves to the greatest extent. ...
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Hyperspectral microscope imaging (HMI) technology as a novel approach was proposed to evaluate physical characteristics of matcha. Particle size distribution as one of the significant physical characteristics was investigated. Data fusion which integrated of textural features from images at 524 nm and key spectral features selected by competitive adaptive reweighed sampling (CARS) were as the raw data for modeling. Models were optimized by cross-validation. Results showed that the performance of models was improved with data fusion. The best ANN models with data fusion were achieved with Rp (correlation coefficient in prediction set) of 0.8020 for D10, 0.8414 for D20, 0.8238 for D30, 0.8124 for D40, 0.8058 for D50, 0.8157 for D60, 0.7643 for D70, 0.7360 for D80, and 0.6313 for D90, respectively. This work demonstrated that HMI technology as a rapid, accurate and high effective protocol has great potential in predicting particle size distribution in matcha powder.
... Phenolic concentrations depend on the growing conditions, such as light, temperature and factors affected by the climate [24]. Green tea contain five major catechins: catechin, epicatechin, epicatechin-3-gallate, epigallocatechin and epigallocatechin gallate [25][26][27]. Rutin, quercetin and kaempferol as well as phenolic acids can also be found in green tea. The amount of leaves used per water or methanol amount is of critical importance as well as the temperature and time of infusion. ...
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Matcha was analysed for its chemical composition, fibre, vitamin C, caffeine and chlorophyll contents. Flavonoids and phenolics, phenolic profiles and antioxidant activity both in water and methanol solutions were determined. In vitro digestibility was established. To understand the contribution of individual substances to antioxidant activity or digestibility their mutual correlations were evaluated. Crude fibre (10.7–17.5%), neutral-detergent fibre (30.7–42.8%) and organic matter digestibility values (59.4–69.7%) showed positive correlations, in contrast to protein contents (20.3–35.0%). It seems that chlorophyll b was a stronger contributor to antioxidant activity than chlorophyll a. The highest contents of flavonoids (99–139 mg RE/g) and phenolics (169–273 mg GAE/g) were determined in methanol fractions. High concentrations of chlorogenic (up to 4800 μg/g), sinapic (up to 1400 μg/g) and gallic acids (up to 423 μg/g) were recorded. Kaempferol and rutin were not proved as significant contributors to antioxidant activity.
... However, it is grown differently and has a unique nutrient profile. The tea bushes are shielded from sunshine for about three or four weeks prior to harvest (Dietz, Dekker, & Piqueras-Fiszman, 2017). This boosts chlorophyll levels, gives beautiful jewel green color and increases amino acid content. ...
Article
Hyperspectral microscope imaging (HMI) technology coupled with chemometrics was attempted to mimic human panel test for estimating sensory quality of matcha in this study. The hypercubes from HMI system contained spatial and spectra information related with quality of samples. Models were established based on the spectra information and the sensory scores from human panel evaluation for sensory attributes. Characteristic spectra were first averaged and extracted from all the pixels in the optimized regions of interest. Then, key spectral variables were selected by competitive adaptive reweighted sampling and used for building artificial neural networks models (namely CARS-ANN models). Results demonstrated that the key spectral variables were only accounted for between 2% and 7% of the original spectral variables for each sensory attribute. The CARS-ANN models achieved superior performance, with 11 spectral variables and 0.7946 of Rp² (coefficient of determination in prediction set) for appearance, 8 spectral variables and 0.7172 of Rp² for infusion color, 21 spectral variables and 0.6747 of Rp² for aroma, 6 spectral variables and 0.7788 of Rp² for taste, 7 spectral variables and 0.7774 of Rp² for overall quality. Overall, HMI technology as a rapid, objective and accurate tool has the potential for estimating quality of matcha.
... A number of foreign authors have shown the positive effect of green tea supplements on drinks and culinary products quality and food technology [5]. Yedygovoy S.N. studied the effect of green tea on the technological properties and physico-chemical parameters of yeast dough. ...
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The problem of micronutrient enrichment and the improvement of the technology for the production of flour confectionery products is relevant. The aim of the work is to study the possibility of using green tea to create sponge cake. The objects of study were Sencha green tea powders (Japan and China), wheat flour, their mixtures in different percentages and sponge cake. According to the obtained experimental data green tea powders is characterized by low humidity (5.0 ± 0.5) % and high acidity (5.8 ± 0.2) %. The content of flavonoids in tea is (52.5 ± 0.5) mg/100 g, the amount of β-carotene - (3.2 ± 0.5) mg/100 g. The following physical-chemical and technological parameters were determined in the finished products: moisture, porosity and swelling. Rheological characteristics of finished products were determined by the device “Structure meter ST-1M”. During storage of products the dynamics of microbiological indicators and water activity over 10 days was determined. The results objectively proved the possibility of using green tea for the production of flour confectionary products. Finished products had high organoleptic and rheological properties. The use of green tea enriched the product with phosphorus, iron, β-carotene and B vitamins.
... In a randomized, placebo-controlled, single-blind study, 23 participants consumed one of the four test products: matcha tea, matcha tea bar (each containing 4 g matcha tea powder), placebo tea, or placebo bar. The results indicated that consumption of matcha, compared to the placebo, significantly improved tasks that measured basic attention abilities and psychomotor speed in response to stimuli, but the effect was barely present in other cognitive tasks [38]. ...
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Abstract: Tea is one of the most consumed beverages in the world. Green tea, black tea, and oolong tea are made from the same plant Camellia sinensis (L.) O. Kuntze. Among them, green tea has been the most extensively studied for beneficial effects on diseases including cancer, obesity, diabetes, and inflammatory and neurodegenerative diseases. Several human observational and intervention studies have found beneficial effects of tea consumption on neurodegenerative impairment, such as cognitive dysfunction and memory loss. These studies supported the basis of tea’s preventive effects of Parkinson’s disease, but few studies have revealed such effects on Alzheimer’s disease. In contrast, several human studies have not reported these favorable effects with regard to tea. This discrepancy may be due to incomplete adjustment of confounding factors, including the method of quantifying consumption, beverage temperature, cigarette smoking, alcohol consumption, and differences in genetic and environmental factors, such as race, sex, age, and lifestyle. Thus, more rigorous human studies are required to understand the neuroprotective effect of tea. A number of laboratory experiments demonstrated the benefits of green tea and green tea catechins (GTCs), such as epigallocatechin gallate (EGCG), and proposed action mechanisms. The targets of GTCs include the abnormal accumulation of fibrous proteins, such as A� and �-synuclein, inflammation, elevated expression of pro-apoptotic proteins, and oxidative stress, which are associated with neuronal cell dysfunction and death in the cerebral cortex. Computational molecular docking analysis revealed how EGCG can prevent the accumulation of fibrous proteins. These findings suggest that GTCs have the potential to be used in the prevention and treatment of neurodegenerative diseases and could be useful for the development of new drugs.
... L-theanine, epigallocatechin gallate (EGCG), caffeine, vitamins, and amino acids are the major components of Camellia sinensis, and it has been reported, in both in vitro and human studies, that each single component has beneficial functions, such as tumor growth suppression and mood enhancing effects (de Souza, Gambeta, Stern, & Zanoveli, 2018;Higashiyama, Htay, Ozeki, Juneja, & Kapoor, 2011;Schröder et al., 2019;Smith, 2002). Notably, Matcha tea is a suspension of the Matcha tea powder containing all the components of the Camellia sinensis leaves and is expected to have various physiological effects such as blood flow improvement, mood improvement, and skin whitening in humans (Dietz, Dekker, & Piqueras-Fiszman, 2017). Furthermore, the Matcha tea powder is believed to have more physiological benefits than green tea, which is only a hot water extract; however, there are only a few scientific studies assessing the effects of the Matcha tea powder itself (Bonuccelli, Sotgia, & Lisanti, 2018;Unno et al., 2018). ...
Article
Matcha is thought to be beneficial for brain functions; however, only a few scientific studies have shown the effects of Matcha tea powder on psychiatric behavior. Here, we evaluated the anxiolytic activity of Matcha tea powder, and its hot water extract (CSW) and ethanol extract (CSE) in mice, using the elevated plus maze test. Oral administration of Matcha tea powder and CSE exerted anxiolytic effects. CSE was further fractionated into hexane soluble (CSEH), ethyl acetate soluble (CSEE) and water soluble (CSEW) fractions. Among the fractions, CSEE and CSEH exerted anxiolytic effects. Moreover, SCH23390, a dopamine D1 receptor blocker, and WAY100135, an antagonist of the serotonin (5-hydroxytryptamine: 5-HT) 1A receptor, prevented Matcha tea powder and CSEE from exerting their anxiolytic effects. These results suggest that Matcha tea powder exerts anxiolytic effect through the activation of the dopaminergic and serotonergic systems.
... Caffeine (1,3,7-trimethylxanthine) is a natural purine alkaloid found in leaves, seeds and fruits of about sixty species in which Coffea canephora (robusta) and Coffea arabica (arabica) are the most common. It is also an additive in many soft drinks and drugs preparations, making it the most consumed drug in the world [1,2]. Numerous studies have shown the neurostimulant action of caffeine in a variety of mammalian models such as rats, and humans. ...
Article
The effects of caffeine supplementation is well documented in conventional animal models, however the effects in the lobster cockroaches Nauphoeta cinerea have not been reported. Thus, we aimed to investigate the locomotor behavior and biochemical endpoints in the head of the nymphs of N. cinerea following 60 days exposure to food supplemented with 0, 0.5, 1.0, 2.5, 5.0 and 10.0 mg of caffeine/g of diet. The analysis of the locomotor behavior using the video-tracking software, Any-maze, for 12 min revealed that caffeine supplementation caused significant behavioral improvement. There was increase in distance travelled, velocity, frequency of rotation and turn angle (stereotypical behavior such as circling movements), and this was supported by the representative track plots of the path travelled by cockroaches in the open-field arena. In addition, caffeine supplementation markedly increased total thiol and non-protein thiol glutathione (GSH) levels in the heads of cockroaches, and this was in parallel with significant reduction of lipid peroxidation and free Fe(II) content. Taking together, our results indicate that long-term caffeine supplementation may exert preventive effects against oxidative stress and support the use of Nauphoeta cinerea as an efficient alternative model to assess the efficacy of food molecules.
... Dietary interventions using polyphenol-rich foods and beverages have demonstrated benefits on several cognitive aspects in humans, including working memory, psychomotor vigilance, and attention across the lifespan. The consumption of polyphenol-or catechin-rich drinks acutely enhances speed, attention, and subjective alertness (Alharbi et al., 2016;Dietz et al., 2017;Haskell-Ramsay et al., 2017). Saenghong and colleagues (2012) demonstrated that two months of supplementation with ginger extract lead to increases in P300 amplitudes during an auditory oddball paradigm in middle-age women (Saenghong et al., 2012). ...
Article
Physical inactivity across the lifespan is a growing public health concern affecting the cardiovascular, musculoskeletal, and central nervous system. Data on the effects of dietary antioxidants as neuroprotective treatments when physical activity levels are impaired are lacking. In this randomized controlled study twenty young healthy men underwent 60 days of bed rest. Participants were randomly assigned to a treatment group (N = 10) receiving a daily antioxidant supplement comprising polyphenols, omega-3 fatty acids, vitamin E, and selenium or a control group (N = 10). Event-related potentials (ERPs) and behavioral data from a three-stimulus oddball paradigm were collected eight days before bed rest, after 60 days of immobilization, and after eight days of recovery. After two months of bed rest, we found a significant decrease in task efficiency irrespective of the treatment that was corroborated by lower ERPs in fronto-central and parietal brain regions. Neither behavioral nor electrocortical data returned to baseline values after eight days of recovery. Our results provide support for the adverse and persistent neurobehavioral effects of prolonged bed rest, which could not be mitigated by antioxidant supplementation. These findings raise important implications for situations in which physical activity levels become severely restricted such as medical conditions or sedentary lifestyles.
... Dietz et al., investigated the effect of matcha tea on cognitive performance and mood in a randomized, placebo-controlled, single blind, crossover study using 4.0 g of matcha tea (containing 280 mg of EGCG) and placebo. Results suggest that matcha tea may induce slight effects on episodic secondary memory and speed attention [113]. Moreover, Mohamed et al., evaluated the cognitive effects of oil palm leaves (OPLE), rich in antioxidant catechins, in adult humans, as well as in a rat model. ...
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In recent years, neurological and neurodegenerative disorders research has focused on altered molecular mechanisms in search of potential pharmacological targets, e.g., imbalances in mechanisms of response to oxidative stress, inflammation, apoptosis, autophagy, proliferation, differentiation, migration, and neuronal plasticity, which occur in less common neurological and neurodegenerative pathologies (Huntington disease, multiple sclerosis, fetal alcohol spectrum disorders, and Down syndrome). Here, we assess the effects of different catechins (particularly of epigalocatechin-3-gallate, EGCG) on these disorders, as well as their use in attenuating age-related cognitive decline in healthy individuals. Antioxidant and free radical scavenging properties of EGCG -due to their phenolic hydroxyl groups-, as well as its immunomodulatory, neuritogenic, and autophagic characteristics, makes this catechin a promising tool against neuroinflammation and microglia activation, common in these pathologies. Although EGCG promotes the inhibition of protein aggregation in experimental Huntington disease studies and improves the clinical severity in multiple sclerosis in animal models, its efficacy in humans remains controversial. EGCG may normalize DYRK1A (involved in neural plasticity) overproduction in Down syndrome, improving behavioral and neural phenotypes. In neurological pathologies caused by environmental agents, such as FASD, EGCG enhances antioxidant defense and regulates placental angiogenesis and neurodevelopmental processes. As demonstrated in animal models, catechins attenuate age-related cognitive decline, which results in improvements in long-term outcomes and working memory, reduction of hippocampal neuroinflammation, and enhancement of neuronal plasticity; however, further studies are needed. Catechins are valuable compounds for treating and preventing certain neurodegenerative and neurological diseases of genetic and environmental origin. However, the use of different doses of green tea extracts and EGCG makes it difficult to reach consistent conclusions for different populations.
... This cooperation enhances the positive effects of caffeine on simple reaction time, rapid information processing accuracy, mental fatigue, and tiredness [18] . Dietz et al. [33] administered 4 g of matcha containing 67 mg of theanine, 280 mg of EGCG, and 136 mg of caffeine to their participants and reported no change in mood on the Profile of Mood States (POMS); however, they did observe improved performance. Similarly, here we observed no change in mood on the VAS after stress loading, but a performance improvement was obtained on attentional function and social cognitive function. ...
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Tea is a beverage commonly consumed worldwide. Matcha is a type of green tea produced by drying and grinding tea leaves (Camellia sinensis L.) into a fine powder. Matcha contains catechin, theanine, and caffeine, which affect cognitive function. Epidemiological studies conducted in Japan have shown that green tea consumption improves cognitive impairment. Previously, we found that daily matcha intake improves attention and executive function in middle-aged and older people. However, its effect on cognitive function in younger adults remains unclear. Moreover, it is unclear which cognitive functions are impaired by stress. This study aimed to clarify whether the administration of matcha improves the attentional function of young adults after mild acute stress and which cognitive function is improved. We included 42 participants aged 25–34 years who consumed 2 g of matcha daily for two weeks. The Uchida–Kraepelin test was used to induce mild acute psychological stress and evaluated memory, attention, facial expression recognition, working memory, visual information, and motor function. Reaction times on the Stroop test for attentional function were significantly lower in the matcha group than in the placebo group. Correct hits in the emotion perception test increased significantly for participants in the matcha group compared to those in the placebo group. We found no significant between-group differences in the other tests. In conclusion, after 2 weeks of matcha intake, the attentional function was maintained after mild acute psychological stress. Thus, matcha might improve cognitive function during or after stress conditions in young adults.
... In an RCT, 23 participants consumed one of the 4 test products: matcha tea (a kind of Japanese green tea), matcha tea bar (each containing 4 g matcha tea powder), placebo tea, or placebo bar. The results indicated that consumption of matcha, compared to the placebo, significantly improved tasks that measure basic attention abilities and psychomotor speed in response to stimuli [147]. Other studies also demonstrated tea's beneficial effects on cognitive impairment. ...
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Many observational and clinical studies have shown that consumption of diets rich in plant polyphenols have beneficial effects on various diseases such as cancer, obesity, diabetes, cardiovascular diseases, and neurodegenerative diseases (NDDs). Animal and cellular studies have indicated that these polyphenolic compounds contribute to such effects. The representative polyphenols are epigallocatechin-3-O-gallate in tea, chlorogenic acids in coffee, resveratrol in wine, and curcumin in curry. The results of human studies have suggested the beneficial effects of consumption of these foods on NDDs including Alzheimer's and Parkinson's diseases, and cellular animal experiments have provided molecular basis to indicate contribution of these representative polyphenols to these effects. This article provides updated information on the effects of these foods and their polyphenols on NDDs with discussions on mechanistic aspects of their actions mainly based on the findings derived from basic experiments.
... Recently, with the rapid increase in tea consumption, matcha tea is popularly recognized worldwide. Research studies have revealed that matcha tea ingestion has significant health benefits such as lessening the possible threats of cardiovascular disease, coronary heart disease, stroke and cancer-related deaths , reducing stress (Unno et al., 2018), anxiolytic properties (Kurauchi et al., 2019), tumour growth suppression (Schröder et al., 2019), liver disease reduction , improving mood and cognitive performance (Dietz, Dekker, & Piqueras-Fiszman, 2017). ...
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Matcha tea is rich in taste and bioactive constituents, quality evaluation of matcha tea is important to ensure flavor and efficacy. Near-infrared spectroscopy (NIR) in combination with variable selection algorithms was proposed as a fast and non-destructive method for the quality evaluation of matcha tea. Total polyphenols (TP), free amino acids (FAA), and polyphenols-to-amino acids ratio (TP/FAA) were assessed as the taste quality indicators. Successive projections algorithm (SPA), genetic algorithm (GA), and simulated annealing (SA) were subsequently developed from the synergy interval partial least squares (SiPLS). The overall results revealed that SiPLS-SPA and SiPLS-SA models combined with NIR exhibited higher predictive capabilities for the effective determination of TP, FAA and TP/FAA with correlation coefficient in the prediction set (Rp) of Rp > 0.97, Rp > 0.98 and Rp > 0.98 respectively. Therefore, this simple and efficient technique could be practically exploited for tea quality control assessment.
... These phenolic compounds especially EGCG are powerful antioxidants with anticancer activities (Ji et al., 2017). Matcha can be consumed directly as tea (Yüksel, Yüksel, & Ş at, 2017), as well as used in the production of pastries (Ivanisova et al., 2018;Phongnarisorn, Orfila, Holmes, & Marshall, 2018), puddings, chocolates, candies (Unno et al., 2019), milk and dairy products (Vu, Mgebrishvili, Hramova, Korotkova, & Gorlov, 2017), and beverages (Dietz, Dekker, & Piqueras-Fiszman, 2017). ...
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This study was realized to determine the effects of whey protein isolate (5% w/v) based edible coatings (WPC) containing different concentrations (3, 6, 9% w/v) of acai powder extract (AE) and matcha extract (ME) on oxidative and microbial stability of cooked meatballs during storage (14 d at +4 °C or 60 d at −18 °C). The antioxidant analysis of the extracts demonstrated that ME had higher total phenolic content and antioxidant capacity than AE (P < 0.05). Results indicated that WPC containing ME delayed lipid oxidation in meatballs during both refrigerated and frozen storage (P < 0.05). Moreover, the use of AE in WPC suppressed microbial growth during both storage conditions (P < 0.05). The edible coating process had no negative effects (P > 0.05) on color, texture, physicochemical composition, and consumer preferences. This result showed that the use of AE and ME in WPC formulation inhibited lipid oxidation and microbial growth, and had the potential for extending shelf-life of meatballs by preserving the physicochemical properties.
... Studies on a mice model that promoted aging reported improvements in cognitive function [14] and the promotion of neurogenesis in the developing hippocampus [15]. In humans, theanine results in improved attention and reaction rates in response to cognitive tasks [8,16], as well as decreased α-amylase activity [17]. Theanine ingestion affects dopamine, serotonin [18], tryptophan, and gamma-aminobutyric acid [19] levels in the brain. ...
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Matcha, a type of green tea, has a higher amino acid content than other types of tea. We previously examined the ability of matcha to improve cognitive function in older adults and determined that continuous matcha intake improves attention and executive function. This study aimed to compare the effects of matcha and caffeine and clarify the differences between these effects. The study was registered at the University Hospital Medical Information Network (UMIN000036578). The effect of single and continuous intake was compared, and the usefulness of continuous intake was evaluated under the stress condition. The Uchida–Kraepelin test (UKT) was used to induce mild acute stress, and the Cognitrax was used to evaluate cognitive function. A single dose of caffeine improved attentional function during or after stress loading. The reduced reaction time in the Cognitrax, observed following a single dose of matcha, was likely due to caffeine. The matcha group showed an increase in the amount of work after continuous intake, whereas the caffeine group only showed an increase in the amount of work for the UKT after a single dose. Ingesting matcha with caffeine improves both attention and work performance when suffering from psychological stress compared with caffeine alone.
... The uniqueness of matcha is that it can be combined with such spreads or fruit juices and even food as a powdered supplement [74]. Dietz et al. [75] have elaborately studied the utility of matcha tea as a mood-and-brain food. Few existing research had confirmed that l-theanine, EGCG, and caffeine affect mood and cognitive performance. ...
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Matcha tea is a traditional Japanese tea that is said to possess ten times higher bioactive components and polyphenols than that of conventional green teas. Matcha is remotely popular among the global community and meagerly researched and infamous among the scientific population. It is the powdered form of green tea leaves that are directly suspended in hot water and drunk without filtration. Matcha is said to be one of the richest antioxidant sources naturally available. This review summarizes the available research publications related to matcha and compares the research accomplishments of green tea and matcha researchers. The fact that green tea is backed up by 35,000 publications while matcha has merely 54 publications to its credit is highlighted in this review for the first time. The future of matcha for tapping its enormous antioxidant activity and health potentials remains connected to the volume of scientific awareness and enhanced research attention in this area. If green tea has so much to offer towards human health and welfare, there is certainly room for more benefits from matcha, which is yet to be disclosed. As public awareness cannot be won without scientific approval, this review seeks that this gap may be bridged using essential knowledge gained from matcha applications and allied research.
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Brewed tea is highly popular around the world and various types are consumed, especially green tea and black tea. Much evidence indicates that tea has a beneficial impact on health. In particular, it appears to be protective against cancer, obesity, metabolic syndrome, type 2 diabetes, cardiovascular disease, and possibly some neurodegenerative diseases. The substance in tea that may be responsible for many of these benefits is (−)-epigallocatechin gallate, a major component of tea catechins. Consumption of up to 3 to 5 cups per day may be recommended for enjoying health benefits.
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Streptococcus pneumoniae is a causative pathogen of several human infectious diseases including community-acquired pneumonia. Pneumolysin (PLY), a pore-forming toxin, plays an important role in the pathogenesis of pneumococcal pneumonia. In recent years, the use of traditional natural substances for prevention has drawn attention because of the increasing antibacterial drug resistance of S. pneumoniae. According to some studies, green tea exhibits antibacterial and antitoxin activities. The polyphenols, namely the catechins epigallocatechin gallate (EGCG), epigallocatechin (EGC), epicatechin gallate (ECG), and epicatechin (EC) are largely responsible for these activities. Although matcha green tea provides more polyphenols than green tea infusions, its relationship with pneumococcal pneumonia remains unclear. In this study, we found that treatment with 20 mg/mL matcha supernatant exhibited significant antibacterial activity against S. pneumoniae regardless of antimicrobial resistance. In addition, the matcha supernatant suppressed PLY-mediated hemolysis and cytolysis by inhibiting PLY oligomerization. Moreover, the matcha supernatant and catechins inhibited PLY-mediated neutrophil death and the release of neutrophil elastase. These findings suggest that matcha green tea reduces the virulence of S. pneumoniae in vitro and may be a promising agent for the treatment of pneumococcal infections.
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The objective of this study was to assess the feasibility of using the plant-source polymer of the matcha powder as a composite admixture for hemihydrate gypsum. Hemihydrate gypsum was mixed with different contents of matcha powder, and then the water requirement for the normal consistency, setting times, density, strength, hydration and microstructure of the hardened mixture were evaluated. The results showed that it increased the water requirement for the normal consistency, and it regulated the setting times and reduced the density. Hemihydrate gypsum with more matcha powder had the higher water requirement, longer setting times and lower density. Less than 1% matcha powder had slight impact on the strength of hardened paste, but more than 1% matcha powder had a remarkable one. Matcha powder changed the hydration process and prolonged the induction and acceleration period. Small needlelike crystals were transformed into longer, larger and thicker ones as more matcha powder was mixed. This case is closely related to the prolongation of the induction and acceleration period. Besides, more and larger pores were observed in the hardened paste with more matcha powder. It is attributed to the appearances of the tea polyphenol in matcha powder and the larger and longer crystal morphology in hardened paste as well as the high water requirement for the normal consistency. These results are important to the application of matcha powder as a composite admixture for the hemihydrate gypsum as well as the prosperity and development of the tea industry.
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The present study compared the microbial population in the samples of steamed green tea and its superfine green tea powder by determining and analyzing microbial changes during ball milling, which is the key step of producing superfine green tea powder. The results showed that after ball milling the microbial counts of superfine green tea powder were dramatically decreased than steam green teas in which the total aerobic count were more than 10⁴ CFU/g in 14/19 samples. With the duration of ball milling, the microbial population of superfine green tea powder was correspondingly decreased till below 10³ CFU/g. To study the mechanism of ball milling on microbial counts’ decreasing, a mold strain was isolated, purified and identified from the samples. Subsequently, the mold strain was cultured and individually ball-milled. The results indicated that fungal cell wall was disrupted and then microbial DNA was released during the process. Moreover, microbial populations in the tea samples were negatively correlated with cell wall breakage ratio. It was suggested that the ball milling was effective strategy for controlling the microbial contamination during the processing of superfine green tea powder.
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The sensory quality of matcha is a pivotal factor in determining consumer acceptance. However, the human sensory panel test is difficult to popularize by virtue of professional requirements and inability to evaluate large samples. The analysis showed that physicochemical indicators of matcha were significantly related to sensory quality. Hence, principal component analysis (PCA) based on selected key physicochemical indicators was proposed to evaluate the sensory quality of matcha in this research. The eight key indicators were selected from twenty-four physicochemical indicators based on least absolute shrinkage and selection operator (LASSO) for the establishment of the PCA comprehensive evaluation model. The results demonstrated that the PCA comprehensive evaluation model achieved superior performance, with -0.895 rc (correlation coefficient in calibration set) and -0.883 rp (correlation coefficient in prediction set) for overall sensory quality. This work demonstrated that LASSO-PCA comprehensive evaluation as an objective protocol has great potential in predicting matcha sensory quality.
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Polyphenols, a category of plant compounds that contain multiple phenol structural units, are widely distributed throughout the plant kingdom and have multiple benefits for human health including anti-obese, anti-hyperglycemic, and anti-hyperlipidemic effects. Additionally, polyphenols have recently gained attention for their anti-stress effects. In this review article, we summarize physiological responses against exposure to stressors and discuss biomarkers for exposure to stressors that are widely used in animal studies and human trials. We also review commonly used animal models for evaluating anti-stress effects. Finally, we discuss recent findings related to the anti-stress effects of polyphenols evaluated in animal models and human trials, and their putative mechanisms. These emerging data require further investigation in scientific studies and human trials to evaluate the anti-stress effects of polyphenols and their potential use for the prevention of stress-related health problems.
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This study aimed to assess the feasibility of identifying multiple chemical constituents in matcha using visible-near infrared hyperspectral imaging (VNIR-HSI) technology. Regions of interest (ROIs) were first defined in order to calculate the representative mean spectrum of each sample. Subsequently, the standard normal variate (SNV) method was applied to correct the characteristic spectra. Competitive adaptive reweighted sampling (CARS) and bootstrapping soft shrinkage (BOSS) were used to optimize the models. They were built based on partial least squares (PLS), creating two models referred to as CARS-PLS and BOSS-PLS. The BOSS -PLS models achieved best predictive accuracy, with coefficients of determination predicted to be 0.8077 for caffeine, 0.7098 for tea polyphenols (TPs), 0.7942 for free amino acids (FAAs), 0.8314 for the ratio of TPs to FAAs, and 0.8473 for chlorophyll. These findings highlight the potential of VNIR-HSI technology as a rapid and nondestructive alternative for simultaneous quantification of chemical constituents in matcha.
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Purpose: The aim of the study is to evaluate the color stability of a conventional composite resin and bulk-fill composite resins. Material Methods: A total of 120 samples of 10 mm diameter and 2 mm thickness were prepared from three bulk-fill (Beautifil Bulk-Fill, Filtek One Bulk-Fill, Tetric N-Ceram Bulk-Fill) and one conventional composite (Z250) and light cured. Initial color measurements were made with a spectrophotometer. Samples for each composite were randomly divided into 3 groups (black, kombucha and matcha tea) (n = 10). The samples were kept in the solutions for 12 days, and the color measurement was repeated. The values of ΔL, Δa, Δb and ΔE00 were calculated. SEM images were taken from a randomly selected sample from each group. Two-way analysis of variance (ANOVA) with Bonferroni correction was used to evaluate the color parameters. Results: Beautifil composite showed the greatest change in all values of E00, ΔL, Δa, and Δb., Filtek One and Tetric N-Ceram had the highest ΔE00 values values after Beautifil, respectively, and there was no difference between Z250 and Tetric N-Ceram. The lowest ΔL value belonged to Z250 composite, there was no difference between Tetric N-Ceram and Filtek One. Tetric N-Ceram had the highest Δa value after Beautifil and, there was no difference between the Z250 and Filtek One. Filtek One had the highest Δb value after Beautifil, there was no difference between the Tetric N-Ceram and Z250. Conclusion: Beverages can negatively affect the surface properties of bulk-fill composite resins in terms of color stability.
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The demand for matcha is growing. This review includes the relationship between quality and components of matcha, researches on foaming and particle sizes, and current state of studies on the health benefits of matcha.
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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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Caffeine is widely consumed and well known for stimulating the central nervous system. When developing new foods and beverages that contain caffeine, it is important to explore the potential synergistic effects of consuming amino acids and other food ingredients with caffeine on humans. Given the physiological pathways affected by the amino acid ornithine, consumption of ornithine with caffeine may have synergistic effects. The purpose of the present study was to examine the effect of consuming caffeine with ornithine in humans. The study used a randomized, placebo-controlled, double-blinded crossover design. The subjects were all healthy office workers who ingested the placebo, 100 mg caffeine, or 100 mg caffeine plus 200 mg ornithine in the morning and completed questionnaires about their mood. Office workers who consumed the combination of caffeine and ornithine had higher mood ratings 8 h after consumption than office workers who consumed caffeine alone. The results of the present study suggest that there is a unique synergistic effect between caffeine and ornithine on the mood of healthy office workers and that ornithine may potentiate the effects of caffeine.
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Tea has been consumed literally for thousands of years and is recognized as a major source of polyphenols in human diet. Polyphenols comprising 20-40% of dry matter in young tea shoots are very important constituents of tea from an intrinsic quality point of view. They are responsible for the colour, flavour and brightness of tea. Recently, tea polyphenols have become a subject of intense studies by scientists throughout the world because of their health beneficial effects and potential uses. On the other hand, there are numerous factors affecting polyphenol structure of tea leaves, such as tea leaf variety, harvesting season, climate, processing method and analytical method. This review is presenting factors affecting polyphenol content and composition of in fresh and processed tea leaves, i.e., green and black teas. Taze ve Đşlenmiş Çay Yapraklarındaki Polifenol Đçeriği ile Dağılımına Etki Eden Faktörler ÖZET Binlerce yıldır tüketilmekte olan çay, diyette polifenollerin ana kaynaklarından biridir. Polifenoller taze çay yapraklarında kuru maddenin %20-40'ını oluşturur ve çay kalitesinin en önemli ögelerinden biridir. Polifenoller çayın renk, lezzet ve parlaklığından sorumlu bileşiklerdir. Son yıllarda çayın sağlık üzerindeki olumlu etkilerinin ve potansiyel kullanım olanaklarının ortaya çıkmasından sonra çay polifenolleri üzerinde daha yoğun olarak çalışılmaya başlanmıştır. Çayın polifenol yapısını etkileyen çok sayıda faktör bulunmaktadır. Bunların başlıcaları çay yaprağı varyetesi, hasat dönemi, işleme yöntemi ve uygulanan analiz metotlarıdır. Bu makalede taze çay yapraklarının ve bunlardan işlenen yeşil ve siyah çayların polifenolleri üzerine etki eden faktörler irdelenmiştir.
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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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Flavonoids and nitrate in a fruit and vegetable diet may be protective against cardiovascular disease and cognitive decline through effects on nitric oxide (NO) status. The circulating NO pool is increased via distinct pathways by dietary flavonoids and nitrate. Our aim was to investigate the acute effects of apples, rich in flavonoids, and spinach, rich in nitrate, independently and in combination on NO status, cognitive function and mood in a randomised, controlled, cross-over trial with healthy men and women (n = 30). The acute effects of four energy-matched treatments (control, apple, spinach and apple + spinach) were compared. Endpoints included plasma nitric oxide status (determined by measuring S-nitrosothiols + other nitroso species (RXNO)), plasma nitrate and nitrite, salivary nitrate and nitrite, urinary nitrate and nitrite as well as cognitive function (determined using the Cognitive Drug Research (CDR) computerized cognitive assessment battery) and mood. Relative to control, all treatments resulted in higher plasma RXNO. A significant increase in plasma nitrate and nitrite, salivary nitrate and nitrite as well as urinary nitrate and nitrite was observed with spinach and apple + spinach compared to control. No significant effect was observed on cognitive function or mood. In conclusion, flavonoid-rich apples and nitrate-rich spinach augmented NO status acutely with no concomitant improvements or deterioration in cognitive function and mood.
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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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Tea is one of the most consumed beverages worldwide, and green tea is the least processed from the buds of the Camellia sinensis plant. The most abundant component of green tea is (-)-epigallocatechin-3-gallate (EGCG), which has been the focus of many cell culture, animal and clinical trials, revealing that EGCG possesses antiproliferative, antimutagenic, antioxidant, antibacterial, antiviral and chemopreventive effects. In this review we briefly summarize the mechanism of action(s) of the green tea component EGCG, highlighting recent advances in the epigenetic regulation by EGCG. Additionally, we provide an overview of mouse chemoprevention studies and EGCG chemoprevention clinical trials.
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Background/Objectives Ingestion of the non-proteinic amino acid l-theanine (γ-glutamylethylamide) has been shown to influence oscillatory brain activity in the alpha band (8–14 Hz) in humans during resting electroencephalographic (EEG) recordings and also during cognitive task performance. We have previously shown that ingestion of a 250-mg dose of l-theanine significantly reduced tonic (background) alpha power during a demanding intersensory (auditory-visual) attentional cueing task. Further, cue-related phasic changes in alpha power, indexing the shorter-term anticipatory biasing of attention between modalities, were stronger on l-theanine compared to placebo. This form of cue-contingent phasic alpha activity is also known to index attentional biasing within visual space. Specifically, when a relevant location is pre-cued, anticipatory alpha power increases contralateral to the location to be ignored. Here we investigate whether the effects of l-theanine on tonic and phasic alpha activity, found previously during intersensory attentional deployment, occur also during a visuospatial task. Subjects/Methods 168-channel EEG data were recorded from thirteen neurologically normal individuals while engaged in a highly demanding visuo-spatial attention task. Participants underwent testing on two separate days, ingesting either a 250-mg colorless and tasteless solution of l-theanine mixed with water, or a water-based solution placebo on each day in counterbalanced order. We compared the alpha-band activity when subjects ingested l-Theanine vs. Placebo. Results We found a significant reduction in tonic alpha for the l-theanine treatment compared to placebo, which was accompanied by a shift in scalp topography, indicative of treatment-related changes in the neural generators of oscillatory alpha activity. However, l-theanine did not measurably affect cue-related anticipatory alpha effects. Conclusions This pattern of results implies that l-theanine plays a more general role in attentional processing, facilitating longer-lasting processes responsible for sustaining attention across the timeframe of a difficult task, rather than affecting specific moment-to-moment phasic deployment processes.
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Background L-theanine, an amino acid contained in green tea leaves, is known to block the binding of L-glutamic acid to glutamate receptors in the brain, and has been considered to cause anti-stress effects by inhibiting cortical neuron excitation. Both L-theanine and caffeine, which green tea contains, have been highlighted for their beneficial effects on cognition and mood. Methods In this study, we investigated the effects of orally administered L-theanine or caffeine on mental task performance and physiological activities under conditions of physical or psychological stress in humans. Fourteen participants each underwent three separate trials, in which they orally took either L-theanine + placebo, caffeine + placebo, or placebo only. Results The results after the mental tasks showed that L-theanine significantly inhibited the blood-pressure increases in a high-response group, which consisted of participants whose blood pressure increased more than average by a performance of a mental task after placebo intake. Caffeine tended to have a similar but smaller inhibition of the blood-pressure increases caused by the mental tasks. The result of the Profile of Mood States after the mental tasks also showed that L-theanine reduced the Tension-Anxiety scores as compared with placebo intake. Conclusions The findings above denote that L-theanine not only reduces anxiety but also attenuates the blood-pressure increase in high-stress-response adults.
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Background/objectives: Green tea is being recognized as a beverage with potential benefits for human health and cognitive functions. In vivo studies provide preliminary evidence that green tea intake may have a positive role in improving effects on cognitive functions. We aimed to examine the neural effects of green tea extract on brain activation in humans. Subjects/methods: Functional magnetic resonance imaging was recorded while 12 healthy volunteers performed a working memory task following administration of 250 or 500 ml of a milk whey based green tea containing soft drink or milk whey based soft drink without green tea as control in a double-blind, controlled repeated measures within-subject design with counterbalanced order of substance administration. A whole-brain analysis with a cluster-level threshold of P<0.001 (unadjusted) was followed by an a priori-defined region of interest (ROI) analysis of the dorsolateral prefrontal cortex (DLPFC) including a cluster-level threshold of P<0.05 and family-wise error (FWE) adjustment for multiple comparisons. Results: Whole-brain analyses revealed no significant effects after correction for multiple comparisons (FWE P<0.05). Using a ROI approach, green tea extract increased activation in the DLPFC relative to a control condition (FWE P<0.001). This neural effect was related to green tea dosage. Green tea extract was not associated with any significant attenuation in regional activation relative to control condition. Conclusions: These data suggest that green tea extract may modulate brain activity in the DLPFC, a key area that mediates working memory processing in the human brain. Moreover, this is the first neuroimaging study implicating that functional neuroimaging methods provide a means of examining how green tea extract acts on the brain.
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The aim of the study was to assess the effects of oral ingestion of the 'green tea' polyphenol epigallocatechin gallate (EGCG) on cognitive performance, mood and localised cerebral blood flow (CBF) parameters in healthy human adults. In this double-blind, placebo-controlled, crossover study, 27 healthy adults received placebo and two doses (135 and 270 mg) of EGCG in counterbalanced order on separate days. Following a 45-min resting absorption period, participants performed a selection of computerised cognitive tasks that activate the frontal cortex for a further 42 min. CBF and haemodynamics, as indexed by concentration changes in oxygenated and deoxygenated haemoglobin, were assessed in the frontal cortex throughout the post-treatment period using Near-infrared spectroscopy (NIRS). During the post-dose task performance period, the administration of 135 mg EGCG resulted in reduced CBF in the frontal cortex, as indexed by significantly lower concentrations of both oxygenated and total haemoglobin, in comparison with placebo. Heart rate was significantly reduced from pre dose to post dose across all treatments. No significant differences were observed for the level of deoxygenated haemoglobin or on any of the cognitive performance/mood measures. These results demonstrate that a single dose of orally administered EGCG can modulate CBF parameters in healthy humans but that this is not associated with changes in cognitive performance or mood.
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The combination of theobromine and caffeine, methylxanthines found in chocolate, has previously been shown to improve mood and cognition. However, it is unknown whether these molecules act synergistically. This study tested the hypothesis that a combination of caffeine and theobromine has synergistic effects on cognition, mood and blood pressure in 24 healthy female subjects. The effects of theobromine (700 mg), caffeine (120 mg) or the combination of both, or placebo were tested on mood (the Bond-Lader visual analog scale), psychomotor performance (the Digit Symbol Substitution Test (DSST)) and blood pressure before and at 1, 2 and 3 h after administration. Theobromine alone decreased self-reported calmness 3h after ingestion and lowered blood pressure relative to placebo 1 h after ingestion. Caffeine increased self-reported alertness 1, 2 and 3h after ingestion and contentedness 1 and 2 h after ingestion, and increased blood pressure relative to placebo (at 1 h). The combination of caffeine+theobromine had similar effects as caffeine alone on mood, but with no effect on blood pressure. There was no treatment effect on DSST performance. Together these results suggest that theobromine and caffeine could have differential effects on mood and blood pressure. It was tentatively concluded that caffeine may have more CNS-mediated effects on alertness, while theobromine may be acting primarily via peripheral physiological changes.
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Recent neuropharmacological research has suggested that certain constituents of tea may have modulatory effects on brain state. The bulk of this research has focused on either L-theanine or caffeine ingested alone (mostly the latter) and has been limited to behavioral testing, subjective rating, or neurophysiological assessments during resting. Here, we investigated the effects of both L-theanine and caffeine, ingested separately or together, on behavioral and electrophysiological indices of tonic (background) and phasic (event-related) visuospatial attentional deployment. Subjects underwent 4 d of testing, ingesting either placebo, 100 mg of L-theanine, 50 mg of caffeine, or these treatments combined. The task involved cued shifts of attention to the left or right visual hemifield in anticipation of an imperative stimulus requiring discrimination. In addition to behavioral measures, we examined overall, tonic attentional focus as well as phasic, cue-dependent anticipatory attentional biasing, as indexed by scalp-recorded alpha-band (8-14 Hz) activity. We found an increase in hit rate and target discriminability (d') for the combined treatment relative to placebo, and an increase in d' but not hit rate for caffeine alone, whereas no effects were detected for L-theanine alone. Electrophysiological results did not show increased differential biasing in phasic alpha across hemifields but showed lower overall tonic alpha power in the combined treatment, similar to previous findings at a larger dosage of L-theanine alone. This may signify a more generalized tonic deployment of attentional resources to the visual modality and may underlie the facilitated behavioral performance on the combined ingestion of these 2 major constituents of tea.
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Among procyanidins (PC), monomers, such as catechin and epicatechin, have been widely studied, whereas dimer and trimer oligomers have received much less attention, despite their abundance in our diet. Recent studies have showed that as dimers and trimers could be important in determining the biological effects of procyanidin-rich food, understanding their bioavailability and metabolism is fundamental. The purpose of the present work is to study the stability of PC under digestion conditions, the metabolism and the bioavailability by using a combination of in vitro and in vivo models. Simultaneously, the matrix effect of a carbohydrate-rich food on the digestibility and bioavailability of PC is investigated. The results show a high level of stability of PC under gastric and duodenal digestion conditions. However, the pharmacokinetic study revealed limited absorption. Free forms of dimers and trimers have been detected in rat plasma, reaching the maximum concentration 1 h after oral intake of a grape seed extract.
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Recent research has shown that even small doses (<40mg) of caffeine can improve alertness and increase performance efficiency on attention tasks. Previous studies have given the caffeine in a variety of beverages or in capsules and it was of interest to see whether similar effects could be observed when the caffeine was given in gum. In addition, chewing gum has been shown to have behavioural effects and the present study extended our knowledge of this topic. To compare the effects of caffeinated gum (40 mg), placebo gum and no gum conditions on mood and attention. A double blind placebo controlled study was conducted with volunteers being randomly assigned to one of the three conditions. Baseline measures of mood and attention were taken prior to chewing and a test session was then conducted. One hundred and eighteen young adults participated in the study. Caffeinated gum was associated with a more positive mood and better performance on tasks requiring sustained attention. The caffeine improved the speed of encoding of new information which is consistent with previous findings. Chewing placebo gum was also found to be associated with more positive mood, both shortly after chewing and at the end of the study. The implications of the present study are that chewing caffeinated gum has been shown to improve performance efficiency and mood by its alerting and energising effects. The profile of caffeine effects is what one would predict from the existing caffeine literature and such effects may be extremely beneficial in real-life situations. Prior chewing of placebo gum was associated with a more positive mood and this also confirms previous findings.
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The effects of a 3mg/kg body weight (BW) dose of caffeine were assessed on behavioral indices of response inhibition. To meet these aims, we selected a modified AX version of the Continuous Performance Test (CPT), the stop task, and the flanker task. In three double-blind, placebo-controlled, within-subjects experiments, these tasks were administered to healthy participants. While the results for the AX-CPT were indicative of improved response inhibition after caffeine, they might also reflect caffeine-induced changes in mechanisms other than response inhibition (e.g., attentional processes). The results for the stop task and flanker task were more straightforward. That is, the effects of caffeine on overall flanker performance and selective response suppression as revealed by distribution-analytical techniques were negligible. In the stop task a global effect of caffeine on processing speed was seen, rather than specific effects on response inhibition. Taken together, these experiments showed that both active and reactive inhibition were not significantly modulated by caffeine. The present results are linked to neural circuits that underlie inhibitory control and the role of caffeine-induced strategic changes.
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Animal evidence indicates that green tea may modulate insulin sensitivity, with epigallocatechin-3-gallate (EGCG) proposed as a likely health-promoting component. The purpose of this study was to investigate the effect of dietary supplementation with EGCG on insulin resistance and associated metabolic risk factors in man. Overweight or obese male subjects, aged 40-65 years, were randomly assigned to take 400 mg capsules of EGCG (n 46) or the placebo lactose (n 42), twice daily for 8 weeks. Oral glucose tolerance testing and measurement of metabolic risk factors (BMI, waist circumference, percentage body fat, blood pressure, total cholesterol, LDL-cholesterol, HDL-cholesterol, TAG) was conducted pre- and post-intervention. Mood was evaluated weekly using the University of Wales Institute of Science and Technology mood adjective checklist. EGCG treatment had no effect on insulin sensitivity, insulin secretion or glucose tolerance but did reduce diastolic blood pressure (mean change: placebo - 0.058 (se 0.75) mmHg; EGCG - 2.68 (se 0.72) mmHg; P = 0.014). No significant change in the other metabolic risk factors was observed. The EGCG group also reported feeling in a more positive mood than the placebo group across the intervention period (mean score for hedonic tone: EGCG, 29.11 (se 0.44); placebo, 27.84 (se 0.46); P = 0.048). In conclusion, regular intake of EGCG had no effect on insulin resistance but did result in a modest reduction in diastolic blood pressure. This antihypertensive effect may contribute to some of the cardiovascular benefits associated with habitual green tea consumption. EGCG treatment also had a positive effect on mood. Further studies are needed to confirm the findings and investigate their mechanistic basis.
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Some previous studies have demonstrated an early effect of caffeine administration on subjective state, but none of them has explored its existence after the administration of decaffeinated coffee, or the possible differences depending on the gender and circadian typology of the subjects. The aim of the present work is to investigate the early effects (10-30 min post-consumption) of a single low dose of caffeine (100 mg) and decaffeinated coffee on sleepiness, subjective activation and affect using a realistic design. The influence of gender and circadian typology is also explored. A randomized double-blind informed placebo controlled procedure was applied to 688 healthy undergraduate volunteers, mean age 22.03+/-2.21 years, 238 men and 450 women. Measures were recorded before and after beverage consumption (10, 20 and 30 min), in two experimental sessions: morning 11:00-13:00 h or afternoon 16:00-18:00 h. Caffeine administration induced arousing effects (lesser somnolence and greater activation) in all post-consumption records, while the effects of decaffeinated drink were only apparent at 10 min. Caffeine effects were greater in men, and the decaffeinated beverage produced greater effects in women. Circadian typology only showed effects for time of day (morning/afternoon) related with rhythmic expression. Future works should study more accurately the early effect of coffee beverages and the influence of gender, using other parameters which have proven to be sensitive to their administration. The effect of several caffeine doses should also be studied.
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The inhibitory activity of tea against tumorigenesis has been demonstrated in many animal models and has been suggested by some epidemiological studies. Such activity has generally been attributed to tea catechins. To understand the bioavailability of tea catechins in humans, we gave 18 individuals different amounts of green tea and measured the time-dependent plasma concentrations and urinary excretion of tea catechins. After taking 1.5, 3.0, and 4.5 g of decaffeinated green tea solids (dissolved in 500 ml of water), the maximum plasma concentration (Cmax) of (-)-epigallocatechin-3-gallate (EGCG) was 326 ng/ml, the Cmax of (-)-epigallocatechin (EGC) was 550 ng/ml, and the Cmax of (-)-epicatechin (EC) was 190 ng/ml. These Cmax values were observed at 1.4-2.4 h after ingestion of the tea preparation. When the dosage was increased from 1.5 to 3.0 g, the Cmax values increased 2.7-3.4-fold, but increasing the dose to 4.5 g did not increase the Cmax values significantly, which suggested a saturation phenomenon. The half-life of EGCG (5.0-5.5 h) seemed to be higher than the half-life of EGC or EC (2.5-3.4 h). EGC and EC, but not EGCG, were excreted in the urine. Over 90% of the total urinary EGC and EC was excreted within 8 h. When the tea dosage was increased, the amount of EGC and EC excretion seemed to increase, but a clear dose-response relationship was not observed. The present study provides basic pharmacokinetic parameters of green tea catechins in humans; these parameters may be used to estimate the levels of these compounds after drinking tea.
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Hippocrates was the first to suggest the healing power of food; however, it was not until the medieval ages that food was considered a tool to modify temperament and mood, although scientific methods as we know them today were not in use at the time. Modern scientific methods in neuroscience began to emerge much later, leading investigators to examine the role of diet in health, including mental wellbeing, with greater precision. This review shows how short- and long-term forced dietary interventions bring about changes in brain structure, chemistry, and physiology, leading to altered animal behavior. Examples will be presented to show how diets alter brain chemistry, behavior, and the action of neuroactive drugs. Most humans and most animal species examined in a controlled setting exhibit a fairly reproducible pattern of what and how they eat. Recent data suggest that these patterns may be under the neurochemical and hormonal control of the organisms themselves. Other data show that in many instances food may be used unconsciously to regulate mood by seemingly normal subjects as well as those undergoing drug withdrawal or experiencing seasonal affective disorders and obesity-related social withdrawal. We will discuss specific examples that illustrate that manipulation of dietary preference is actually an attempt to correct neurochemical make-up.
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Nutritional oncology is an increasingly active interdisciplinary field where cancer is investigated as both a systemic and local disease originating with the changes in the genome and progressing through a multi-step process which may be influenced at many points in its natural history by nutritional factors that could impact the prevention of cancer, the quality of life of cancer patients, and the risk of cancer recurrence in the rapidly increasing population of cancer survivors. Since the first edition of this book was published in 1999, the idea that there is a single gene pathway or single drug will provide a cure for cancer has given way to the general view that dietary/environmental factors impact the progression of genetic and cellular changes in common forms of cancer. This broad concept can now be investigated within a basic and clinical research context for specific types of cancer. This book attempts to cover the current available knowledge in this new field of nutritional oncology written by invited experts. This book attempts to provide not only the theoretical and research basis for nutritional oncology, but will offer the medical oncologist and other members of multidisciplinary groups treating cancer patients practical information on nutrition assessment and nutritional regimens, including micronutrient and phytochemical supplementation. The editors hope that this volume will stimulate increased research, education and patient application of the principles of nutritional oncology. NEW TO THIS EDITION * Covers hot new topics of nutrigenomics and nutrigenetics in cancer cell growth * Includes new chapters on metabolic networks in cancer cell growth, nutrigenetics and nutrigenomics * Presents substantially revised chapters on breast cancer and nutrition, prostate cancer and nutrition, and colon cancer and nutrition * Includes new illustrations throughout the text, especially in the breast cancer chapter * Includes integrated insights into the unanswered questions and clearly defined objectives of research in nutritional oncology * Offers practical guidelines for clinicians advising malnourished cancer patients and cancer survivors on diet, nutrition, and lifestyle * Provides information on the role of bioactive substances, dietary supplements, phytochemicals and botanicals in cancer prevention and treatment.
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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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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.
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Both epidemiological and laboratory studies have suggested an inverse association between consumption of green tea and the prevalence of some cancers. The anti-tumorigenicity of green tea has been related to its content of specific polyphenols. The molecular mechanisms underlying the anticancer and antiangiogenic effects of green tea polyphenols (GTPs) are currently under intensive investigation. The purpose of this article is to update a previous review on the effects and biological activities of GTPs in relation to their therapeutic usefulness in preventing cancer in humans [1]. GTPs mainly consist of catechins (3-flavanols), of which epigallocatechin gallate (EGCG) is the most abundant in green tea and the most extensively studied. Moreover, the biological effects reported for GTPs have been mainly associated to EGCG. New perspectives on the applications of dietary GTPs as potential therapeutic and preventive agents against cancer are presented.
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Oxidative stress induced by hypertension has been reported to cause alterations in neural cytoarchitecture and cognitive dysfunction. Green tea catechins, especially (-)-epigallocatechin-3-gallate (EGCG), have potent antioxidative properties and protect against various oxidative damages. In this study, we examined the impact of hypertension in rats on locomotor activity, learning, and memory, and EGCG was tested for its potential therapeutic effects in treating hypertension-induced impairment. Blood pressure was measured by the tail-cuff method to confirm high blood pressure in spontaneous hypertension rats (SHRs). Locomotor activity in the open field was increased in SHRs, along with learning and memory impairment in the Morris water maze. Daily EGCG treatment reduced the progressive increase in blood pressure in SHRs, and prevented most of the increased locomotor activity in addition to improving learning and memory. EGCG treatment also decreased the increased level of lipid peroxide production in SHRs and enhanced the antioxidation power in plasma that was observed to be decreased in SHRs. EGCG also decreased the concentration of reactive oxygen species in the hippocampi of SHRs. These indicate a therapeutic effect of EGCG in treating hypertension-induced learning and memory impairment, most probably through its powerful antioxidative properties.
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Of the known biochemical actions of caffeine, only inhibition of adenosine receptors occurs at concentrations achieved during normal human consumption of the drug. Under normal physiological conditions, adenosine is present in sufficient concentrations to activate A1 and A2a receptors. Via actions on A, receptors, adenosine decreases neuronal firing and the release of neurotransmitters. The exact mechanisms are not known, but several possibilities are discussed. Via actions on A2a receptors, adenosine - and hence caffeine - can influence dopaminergic neurotransmission. Caffeine can induce rapid changes in gene expression and, somewhat later, marked adaptive changes. These include antiepileptic and neuroprotective changes. Thus, caffeine has a number of central effects directly or indirectly related to adenosine receptors. Some of these are potentially useful, and drug development based on the actions of caffeine should be interesting.
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Energy drinks containing caffeine, taurine, and glucose may improve mood and cognitive performance. However, there are no studies assessing the individual and interactive effects of these ingredients. We evaluated the effects of caffeine, taurine, and glucose alone and in combination on cognitive performance and mood in 24-hour caffeine-abstained habitual caffeine consumers. Using a randomized, double-blind, mixed design, 48 habitual caffeine consumers (18 male, 30 female) who were 24-hour caffeine deprived received one of four treatments (200 mg caffeine/0 mg taurine, 0 mg caffeine/2000 mg taurine, 200 mg caffeine/2000 mg taurine, 0 mg caffeine/0 mg taurine), on each of four separate days, separated by a 3-day wash-out period. Between-participants treatment was a glucose drink (50 g glucose, placebo). Salivary cortisol, mood and heart rate were measured. An attention task was administered 30-minutes post-treatment, followed by a working memory and reaction time task 60-minutes post-treatment. Caffeine enhanced executive control and working memory, and reduced simple and choice reaction time. Taurine increased choice reaction time but reduced reaction time in the working memory tasks. Glucose alone slowed choice reaction time. Glucose in combination with caffeine, enhanced object working memory and in combination with taurine, enhanced orienting attention. Limited glucose effects may reflect low task difficulty relative to subjects' cognitive ability. Caffeine reduced feelings of fatigue and increased tension and vigor. Taurine reversed the effects of caffeine on vigor and caffeine-withdrawal symptoms. No effects were found for salivary cortisol or heart rate. Caffeine, not taurine or glucose, is likely responsible for reported changes in cognitive performance following consumption of energy drinks, especially in caffeine-withdrawn habitual caffeine consumers.
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The effect of different extraction conditions and storage time of prepared infusions on the content of bioactive compounds of green teas and their antioxidant capacity were investigated. The content of total phenols, total flavonoids and total non-flavonoids in green teas was determined spectrophotometrically, while 7 flavan-3-ols, 6 phenolic acids and 3 methylxanthines were identified and quantified by using high performance liquid chromatography (HPLC–PDA). Among the tested green teas bagged green tea Twinings of London was recognized as the richest source of phenolic compounds (3585 mg/L GAE of total phenols). The most abundant phenolic constituents of green tea were flavan-3-ols, of which EGCG was prevailing in all teas (94.54–357.07 mg/L). The highest content of caffeine, as the most abundant methylxanthine, was determined in powdered green tea. The findings of this investigation suggest that extraction efficiency of studied bioactive compounds from green tea depends on the extraction conditions and that maximum extraction efficiency is achieved during aqueous extraction at 80 °C, for 5′ (powder), 15′ (bagged) and 30′ (loose leaf). In order to determine the antioxidant capacity of teas the DPPH, ABTS and FRAP assays were applied. Regardless of the extraction conditions all green teas exhibited significant antioxidant capacity in vitro, which was in correlation with their phenolic content, confirming that green tea is one of the best dietary sources of antioxidants.
Article
Green tea is reported to have wide ranging beneficial health outcomes across epidemiological studies, which have been attributed to its flavonoid content. We investigated whether the flavonoid epigallocatechin gallate (EGCG) modulates brain activity and self-reported mood in a double-blind, placebo controlled crossover study. Participants completed baseline assessments of cognitive and cardiovascular functioning, mood and a resting state electroencephalogram (EEG) before and then 120 min following administration of 300 mg EGCG or matched placebo. EGCG administration was associated with a significant overall increase in alpha, beta and theta activity, also reflected in overall EEG activity, more dominant in midline frontal and central regions, specifically in the frontal gyrus and medial frontal gyrus. In comparison to placebo the EGCG treatment also increased self-rated calmness and reduced self rated stress. This pattern of results suggests that participants in the EGCG condition may have been in a more relaxed and attentive state after consuming EGCG. This is in keeping with the widespread consumption of green tea for its purported relaxing/refreshing properties. The modulation of brain function due to EGCG is deserving of further controlled human studies.
Article
In this paper, a novel application of alternating penalty trilinear decomposition (APTLD) for high-performance liquid chromatography with fluorescence detection (HPLC-FLD) has been developed to simultaneously determine the contents of free amino acids in tea. Although the spectra of amino acid derivatives were similar and a large number of water-soluble compounds are coextracted, APTLD could predict the accurate concentrations together with reasonable resolution of chromatographic and spectral profiles for the amino acids of interest owing to its "second-order advantage". An additional advantage of the proposed method is lower cost than traditional methods. The results indicate that it is an attractive alternative strategy for the routine resolution and quantification of amino acids in the presence of unknown interferences or when complete separation is not easily achieved.
Article
Studies indicate that the change from closed to open eyes in a resting condition results in an increase in skin conductance level (SCL) and a global decrease in EEG alpha activity, both indicative of increased arousal. Other studies show that ingestion of caffeine also produces SCL increase and alpha reduction. This study investigated the additivity of the effects of these two independent arousing variables. EEG activity and SCL were recorded from 22 university students during both eyes-closed and eyes-open resting conditions, under the action of both caffeine and placebo, in a counterbalanced randomised double-blind study. SCL increased significantly from eyes-closed to eyes-open conditions, and from placebo to caffeine, with no interaction. Global reductions in EEG alpha amplitude were apparent with opening of the eyes and caffeine ingestion; again, there was no interaction. Caffeine had a larger effect than opening the eyes on SCL, but their relative effect sizes were reversed in alpha. The two dependent measures showed the predicted negative correlation in both eyes-closed placebo and eyes-open caffeine conditions, with the latter substantially reduced relative to the former. Caffeine and opening the eyes have additive effects on two measures of arousal, increasing SCL and reducing global EEG alpha. However, the independent variable effects are not equivalent, suggesting that one or both measures reflect additional non-arousal processes. As caffeine is widely used by both children and adults, knowledge of the additivity of arousal effects of caffeine and opening the eyes is important in controlling participant state in EEG studies. The current results confirm the use of mean global alpha amplitude as a measure of resting-state arousal, but also point to non-arousal effects of visual input.