***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: L-Theanine is an amino acid found naturally in tea . Despite the common consumption of L-theanine , predominantly in combination with caffeine in the form of tea , only one study to date has examined the cognitive effects of this substance alone , and none have examined its effects when combined with caffeine . The present r and omised , placebo-controlled , double-blind , balanced crossover study investigated the acute cognitive and mood effects of L-theanine ( 250 mg ) , and caffeine ( 150 mg ) , in isolation and in combination . Salivary caffeine levels were co-monitored . L-Theanine increased ' headache ' ratings and decreased correct serial seven subtractions . Caffeine led to faster digit vigilance reaction time , improved Rapid Visual Information Processing ( RVIP ) accuracy and attenuated increases in self-reported ' mental fatigue ' . In addition to improving RVIP accuracy and ' mental fatigue ' ratings , the combination also led to faster simple reaction time , faster numeric working memory reaction time and improved sentence verification accuracy . ' Headache ' and ' tired ' ratings were reduced and ' alert ' ratings increased . There was also a significant positive caffeine x L-theanine interaction on delayed word recognition reaction time . These results suggest that beverages containing L-theanine and caffeine may have a different pharmacological profile to those containing caffeine alone 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 assessment s 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-b and ( 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 re sources to the visual modality and may underlie the facilitated behavioral performance on the combined ingestion of these 2 major constituents of tea OBJECTIVE L-theanine is a unique amino acid present almost exclusively in the tea plant . It possesses neuroprotective , mood-enhancing , and relaxation properties . This is a first study design ed to evaluate the efficacy and tolerability of L-theanine augmentation of antipsychotic treatment of patients with chronic schizophrenia and schizoaffective disorder . METHOD 60 patients with DSM-IV schizophrenia or schizoaffective disorder participated in an 8-week , double-blind , r and omized , placebo-controlled study . 400 mg/d of L-theanine was added to ongoing antipsychotic treatment from February 2006 until October 2008 . The outcome measures were the Positive and Negative Syndrome Scale ( PANSS ) , the Hamilton Anxiety Rating Scale ( HARS ) , the Cambridge Neuropsychological Test Automated Battery ( CANTAB ) for neurocognitive functioning , and additional measures of general functioning , side effects , and quality of life . RESULTS 40 patients completed the study protocol . Compared with placebo , L-theanine augmentation was associated with reduction of anxiety ( P = .015 ; measured by the HARS scale ) and positive ( P = .009 ) and general psychopathology ( P < .001 ) scores ( measured by the PANSS 3-dimensional model ) . According to the 5-dimension model of psychopathology , L-theanine produced significant reductions on PANSS positive ( P = .004 ) and activation factor ( P = .006 ) scores compared to placebo . The effect sizes ( Cohen d ) for these differences ranged from modest to moderate ( 0.09 - 0.39 ) . PANSS negative and CANTAB task scores , general functioning , side effect , and quality of life measures were not affected by L-theanine augmentation . L-theanine was found to be a safe and well-tolerated medication . CONCLUSIONS L-theanine augmentation of antipsychotic therapy can ameliorate positive , activation , and anxiety symptoms in schizophrenia and schizoaffective disorder patients . Further long-term studies of L-theanine are needed to substantiate the clinical ly significant benefits of L-theanine augmentation Tea ingredients L-theanine and caffeine have repeatedly been shown to deliver unique cognitive benefits when consumed in combination . The current r and omized , placebo-controlled , double-blind , cross-over study compared a combination of L-theanine ( 97 mg ) and caffeine ( 40 mg ) to a placebo on two attention tasks and a self-report question naire before , and 10 and 60 min after consumption . The combination of L-theanine and caffeine significantly improved attention on a switch task as compared to the placebo , while subjective alertness and intersensory attention were not improved significantly . The results support previous evidence that L-theanine and caffeine in combination can improve attention Most systematic review s rely substantially on the assessment of the method ological quality of the individual trials . The aim of this study was to obtain consensus among experts about a set of generic core items for quality assessment of r and omized clinical trials ( RCTs ) . The invited participants were experts in the field of quality assessment of RCTs . The initial item pool contained all items from existing criteria lists . Subsequently , we reduced the number of items by using the Delphi consensus technique . Each Delphi round comprised a question naire , an analysis , and a feedback report . The feedback report included staff team decisions made on the basis of the analysis and their justification . A total of 33 international experts agreed to participate , of whom 21 completed all question naires . The initial item pool of 206 items was reduced to 9 items in three Delphi rounds . The final criteria list ( the Delphi list ) was satisfactory to all participants . It is a starting point on the way to a minimum reference st and ard for RCTs on many different research topics . This list is not intended to replace , but rather to be used alongside , existing criteria lists Objective : Ingestion of the nonproteinic amino acid theanine ( 5-N-ethylglutamine ) has been shown to increase oscillatory brain activity in the so-called alpha b and ( 8 - 14 Hz ) during resting electroencephalographic recordings in humans . Independently , alpha b and activity has been shown to be a key component in selective attentional processes . Here , we set out to assess whether theanine would cause modulation of anticipatory alpha activity during selective attentional deployments to stimuli in different sensory modalities , a paradigm in which robust alpha attention effects have previously been established . Methods :  Electrophysiological  data from 168 scalp electrode channels were recorded while participants performed a st and ard intersensory attentional cuing task . Results : As in previous studies , significantly greater alpha b and activity was measured over parieto-occipital scalp for attentional deployments to the auditory modality than to the visual modality . Theanine ingestion result ed in a substantial overall decrease in background alpha levels relative to placebo while subjects were actively performing this dem and ing attention task . Despite this decrease in background alpha activity , attention-related alpha effects were significantly greater for the theanine condition . Conclusion : This increase of attention-related anticipatory alpha over the right parieto-occipital scalp suggests that theanine may have a specific effect on the brain 's attention circuitry . We conclude that theanine has clear psychoactive properties , and that it represents a potentially interesting , naturally occurring compound for further study , as it relates to the brain 's attentional system OBJECTIVE The aim of this study was to investigate green tea flavan-3-ol catabolism and plasma pharmacokinetic and urinary excretion by high-performance liquid chromatography with t and em mass spectrometry to evaluate their absolute bioavailability by taking into account all known and some unknown catabolites deriving from their interaction with the gastrointestinal tract and its host microflora . METHODS A feeding study was carried out in 20 healthy human volunteers who ingested 400 mL of a ready-to-drink green tea containing approximately 400 μmol of flavan-3-ols . Urine and plasma were collected for 4 and 24h , respectively , and 39 relevant catabolites were identified in these biological fluids by t and em mass spectrometry . RESULTS In biological fluids , 39 relevant flavan-3-ol catabolites were identified . In plasma , (-)-epigallocatechin-3-gallate was the only unmetabolized compound and the highest in absolute concentration compared with (-)-epigallocatechin and (-)-epicatechin conjugates . Colonic microflora-derived polyhydroxyphenyl-γ-valerolactones were by far the main urinary catabolites , averaging 10 times greater concentratin than flavan-3-ol conjugates . The calculated bioavailability was equal to 39 % and it is interesting to notice the great variability in urinary excretion of colonic metabolites among participants , probably related to differences in their own colonic microflora . CONCLUSION This study demonstrates that green tea catechins are more bioavailable than previously observed when colonic ring fission metabolites are taken into consideration . Regular consumption of ready-to-drink green tea containing flavan-3-ols allows a non-marginal exposure of the human body to these catabolites , somehow justifying the numerous beneficial actions described as linked to green tea intake 
    Output:
    
The effects of green tea can not be attributed to a single constituent of the beverage .
This is exemplified in the finding that beneficial green tea effects on cognition are observed under the combined influence of both caffeine and l-theanine , whereas separate administration of either substance was found to have a lesser impact