L-Theanine and Caffeine in Combination Affect Human Cognition as Evidenced by Oscillatory alpha-Band Activity and Attention Task Performance
Open accessAbstract
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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Written from the paper’s full text.
TL;DR
In a four-day repeated-measures study, combined L-theanine (100 mg) and caffeine (50 mg) improved visuospatial attention performance and reduced tonic alpha-band EEG power relative to placebo. Caffeine alone improved discriminability but not hit rate, while L-theanine alone at this lower dose produced no significant behavioral or tonic-alpha effects.
Key findings
- The combined treatment increased hit rate and target discriminability relative to placebo; the hit-rate improvement was about 3%, and the discriminability effect size was larger for the combination (Cohen’s d = 0.55) than for caffeine alone (d = 0.42).
- Caffeine alone improved discriminability relative to placebo but did not improve hit rate; no treatment affected reaction time.
- L-theanine alone at 100 mg produced no significant behavioral effects and did not significantly lower tonic alpha, unlike prior findings at 250 mg.
- Tonic alpha power was significantly lower for the combined treatment than placebo; the alpha cueing effect was smaller for caffeine alone than placebo, but not for L-theanine alone or the combination.
Methods
- Sixteen neurologically normal paid volunteers (5 female; ages 21–40, mean 27.5 years) completed four counterbalanced testing days, receiving placebo, 100 mg L-theanine, 50 mg caffeine, or both combined, with task runs beginning 30 min after ingestion.
- Participants performed a cued visuospatial attention task requiring covert shifts to left or right locations and discrimination of target versus standard stimuli, while continuous EEG was recorded from 164 scalp electrodes plus EOG.
- Behavioral analyses used hit rate, false alarm rate, discriminability index, and reaction time; EEG analyses examined tonic alpha amplitude before cue onset and lateralized anticipatory alpha after cue onset using temporal spectral evolution.
Limitations
- The authors caution that synergy between L-theanine and caffeine cannot be strongly claimed because only single doses were tested and the combined condition did not differ significantly from caffeine alone on tonic alpha.
- The authors note that alpha effects of both compounds appear dose-dependent and call for future dose-response characterization; the caffeine-alone alpha reduction did not reach significance (P = 0.18).
- The unexpected reduction in the alpha cueing effect for caffeine alone is described as needing replication; more generally, the small sample and single-dose design limit generalization.
Model-written summary. Check it against the paper before relying on it.
Integrity signals
Registry
Cites
Statistics
Claims the paper makes
3 of 17 cited sources checked · 2 supported · 0 flagged · accuracy not yet measured
- Premisecitation
L-theanine ingestion increases alpha-band activity during rest.
“Using electroencephalographic (EEG) recordings in humans, Kobayashi et al. (12) and Juneja et al. (13) reported that activity within the alpha frequency band (8-14 Hz) increased in reaction to L-theanine ingestion when measured during a state of rest.”
Quote in the paperSubstantial claim1 of 2 sources checked - Findingown data
Tonic alpha amplitude was significantly lower after the combined treatment than after placebo.
“Follow-up t-tests revealed that alpha was significantly lower for T1C than P (P , 0.02).”
- Also stated in: § Abstract · plain
“showed lower overall tonic alpha power in the combined treatment”
Quote in the paperSubstantial claim - Also stated in: § Abstract · plain
- Findingown data
Ingesting 100 mg L-theanine together with 50 mg caffeine raised the proportion of valid targets detected compared with placebo.
“Behavioral performance was significantly improved on the combined treatment (T1C) in terms of hit rate (P , 0.016) and d# (P , 0.002).”
- Also stated in: § Abstract · plain
“We found an increase in hit rate and target discriminability (d#) for the combined treatment relative to placebo”
Quote in the paperSubstantial claim - Also stated in: § Abstract · plain
- Findingown data
Tonic alpha amplitude after L-theanine alone did not differ significantly from placebo.
“P did not differ from either T or C (see Fig. 2).”
Quote in the paperNot a substantial claim - Findingown data
Caffeine alone at 50 mg did not improve hit rate relative to placebo.
“There was also a significant improvement in d# on C compared with P (P , 0.016), but not in hit rate.”
- Also stated in: § Abstract · plain
“and an increase in d# but not hit rate for caffeine alone”
Quote in the paperNot a substantial claim - Also stated in: § Abstract · plain
- Findingown data
A typical alpha cueing effect, reflecting an attention by hemisphere interaction, was present in pretarget anticipatory alpha measures on each treatment day.
“The typical alpha cueing effect was readily apparent in both the nonnormalized alpha amplitude waveforms and normalized pretarget measures (Fig. 3) for each treatment day.”
- Also stated in: § ). · boosted
“A strong attention 3 hemisphere interaction (P , 0.0005) was found on the pretarget anticipatory alpha measures as expected, reflecting the typically observed alpha-mediated cueing effect.”
Quote in the paperNot a substantial claim - Also stated in: § ). · boosted
- Findingown data
The combined L-theanine and caffeine treatment improved the discriminability index d' relative to placebo.
“Behavioral performance was significantly improved on the combined treatment (T1C) in terms of hit rate (P , 0.016) and d# (P , 0.002).”
- Also stated in: § Abstract · plain
“We found an increase in hit rate and target discriminability (d#) for the combined treatment relative to placebo”
Quote in the paperSubstantial claim - Also stated in: § Abstract · plain
- Findingown data
Caffeine alone at 50 mg improved d' relative to placebo.
“There was also a significant improvement in d# on C compared with P (P , 0.016), but not in hit rate.”
- Also stated in: § Abstract · plain
“and an increase in d# but not hit rate for caffeine alone”
Quote in the paperSubstantial claim - Also stated in: § Abstract · plain
- Findingown data
A significant three-way interaction of treatment, attention, and hemisphere was found for pretarget anticipatory alpha.
“In addition, there was a significant 3-way interaction among treatment, attention, and hemisphere (P , 0.05).”
Quote in the paperSubstantial claim - Findingown data
The alpha cueing effect was smaller after caffeine alone than after placebo.
“When we reduced the alpha cueing effect to a single metric as described above, the effect was smaller on C than P (P , 0.02) but did not differ for the T or T1C conditions.”
Quote in the paperSubstantial claim - Findingown data
Tonic alpha amplitude did not differ significantly between the combined treatment and caffeine alone.
“Tonic alpha differed between T1C and T (P , 0.005) but not between T1C and C.”
Quote in the paperNot a substantial claim - Findingown data
None of the three active treatments changed reaction time relative to placebo.
“There were no significant effects of L-theanine, and no effects of any of the 3 treatments on RT”
Quote in the paperNot a substantial claim - Findingown data
Tonic alpha amplitude after caffeine alone did not differ significantly from placebo.
“P did not differ from either T or C (see Fig. 2).”
Quote in the paperNot a substantial claim - Findingown data
Tonic alpha amplitude was significantly lower after the combined treatment than after L-theanine alone.
“Tonic alpha differed between T1C and T (P , 0.005) but not between T1C and C.”
Quote in the paperSubstantial claim - Interpretationreasoning
Because caffeine alone did not change hit rate, its d' improvement is attributable to a reduction in false alarms.
“Given the absence of any difference in hit rate for caffeine, the d# effect must result from subjects making fewer false alarms on caffeine.”
Quote in the paperNot a substantial claim - Interpretationown data
The combined treatment's greater tonic alpha decrease suggests synergy between L-theanine and caffeine.
“That this decrease marks a synergy between the 2 compounds is suggested by the numerical difference in the alpha decrease caused by L-theanine with and without caffeine (Fig. 2).”
Quote in the paperSubstantial claim - Interpretationreasoning
The larger tonic alpha decrease with the combined treatment is unlikely to be merely the sum of the decreases produced by each compound alone.
“That is, it seems unlikely that the greater decrease on the combined treatment is simply a linear sum of the decreases from each compound alone.”
Quote in the paperSubstantial claim - Interpretationcitation
The alpha effects of both L-theanine and caffeine depend on dose.
“From this, it is clear that alpha effects of both L-theanine and caffeine are dose dependent, demonstrating that full characterization of dose-response functions in future studies is called for.”
Quote in the paperSubstantial claim - Premisecitation
L-theanine does affect cued attentional biasing between sensory modalities.
“In contrast, the cued biasing of attention between sensory modalities does appear to be affected (18).”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [18] Gomez-Ramirez, 2007, The deployment of intersensory selective attention: a high-density electrical mapping study of the effects of theanine, Clin Neuropharmacol. source
- Interpretationown data
L-theanine does not affect attentional biasing within visual space as indexed by alpha amplitude.
“For now, it appears that within visual space, attentional biasing as indexed by alpha amplitude is not affected by L-theanine.”
Quote in the paperSubstantial claim - Study design and conductreasoning
The z-score normalization cannot bias treatment comparisons because each day contains equal numbers of observations from every treatment.
“Because the distribution of scores for each day contains an equal number of data points from each treatment, it cannot result in any bias for treatment but, rather, optimizes statistical power to test for treatment effects.”
Quote in the paperSubstantial claim - Premiseown data
A previous visuospatial attention study found that 250 mg L-theanine did not increase the differential effect of attention.
“L-Theanine, at a dosage of 250 mg, was not found to increase the differential effect of attention.”
Quote in the paperSubstantial claim - Premisecitation
In a prior study, 250 mg L-theanine increased the differential effect of cue information on anticipatory alpha amplitude relative to placebo.
“In Gomez-Ramirez et al. (18), this differential effect of cue information on anticipatory alpha amplitude was found to be larger on ingestion of 250 mg of L-theanine relative to placebo.”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [18] Gomez-Ramirez, 2007, The deployment of intersensory selective attention: a high-density electrical mapping study of the effects of theanine, Clin Neuropharmacol. source
- Interpretationreasoning
The decrease in alpha caused by L-theanine is a reliable effect.
“This study marks the third finding of decreased alpha as a result of L-theanine ingestion (albeit a partial cause here) to date, demonstrating the reliability of the effect.”
Quote in the paperSubstantial claim - Premisecitation
Evidence indicates that caffeine alone cannot fully explain the positive effects of tea drinking.
“there exists evidence that caffeine alone cannot fully account for the positive effects of tea drinking.”
Quote in the paperSubstantial claim0 of 2 sources checked
- Classified as probably not a substantial claim. 12
- The quote only partly states this claim. 1
- May combine two claims. 9
Probably not a substantial claim: may not pass S3 (load-bearing).
PremisecitationHigher caffeine doses, 200 mg and 400 mg, reduce absolute alpha power during resting with eyes open.
“Previous studies have reported a drop in absolute alpha power during resting with eyes open on ingestion of caffeine at higher dosages, e.g., 200 mg (30) and 400 mg (31).”
Quote in the paperNot a substantial claim2 of 2 sources checked- cites [30] Siepmann, 2002, Effects of caffeine on topographic quantitative EEG, Neuropsychobiology. source
- cites [31] Deslandes, 2005, Effects of caffeine on the electrophysiological, cognitive and motor responses of the central nervous system, Braz J Med Biol Res. source
The Abstract reports that 400 mg of caffeine significantly reduced alpha absolute power, but specifies that the resting EEG was recorded with eyes closed. The Quantitative electroencephalographic analyses section distinguishes this study's eyes-closed condition from earlier studies with significant results in subjects tested with eyes open. This source therefore supports the 400 mg reduction, not the claimed eyes-open condition. (LLM, conf=0.90)
Experimental — accuracy not yet measured
The quote only partly states this claim.
Findingown dataL-theanine alone at 100 mg produced no significant change in hit rate, d', or reaction time relative to placebo.
“There were no significant effects of L-theanine, and no effects of any of the 3 treatments on RT”
- Also stated in: § Abstract · plain
“whereas no effects were detected for L-theanine alone.”
Quote in the paperSubstantial claim- Rests on an assumption: A typical serving of tea contains roughly 100 mg L-theanine and 50 mg caffeine.
- Also stated in: § Abstract · plain
May combine two claims.
Findingown dataThe alpha cueing effect did not differ from placebo for L-theanine alone or for the combined treatment.
“When we reduced the alpha cueing effect to a single metric as described above, the effect was smaller on C than P (P , 0.02) but did not differ for the T or T1C conditions.”
Quote in the paperSubstantial claimClassified as probably not a substantial claim.
Study design and conductreasoningBehavioral scores were converted to z-scores within each testing day to remove practice-related variance.
“Thus, a normalization of these measures was necessary to remove the variance caused by practice, and this was carried out by transforming each data point to a z-score with respect to the mean and SD of all scores measured on that day (d 1, d 2, d 3, d 4).”
Quote in the paperSubstantial claimMay combine two claims.
InterpretationreasoningL-theanine enhances the tonic allocation of attentional resources to the visual modality, significantly when a large dose is taken alone or when a smaller dose is combined with caffeine.
“A tentative interpretation of the current pattern of results is that L-theanine works to enhance the tonic apportionment of attentional resources to the visual modality and does so to a significant degree when a large dosage is ingested by itself or in combination with caffeine when a smaller dosage is ingested.”
Quote in the paperSubstantial claimClassified as probably not a substantial claim. May combine two claims.
PremisecitationThe alpha rhythm is sensitive to overall attentional states and participates in selective attention biasing.
“This was of interest to the attention community, as the alpha rhythm has long been known to be sensitive to overall attentional states (i.e., intensity aspects such as arousal) (14) and, further, is involved in the biasing of selective attention (15,16).”
Quote in the paperSubstantial claim0 of 3 sources checked- cites [14] Adrian, 1934, The Berger Rhythm: Potential changes in the occipital lobes in man, Brain. source
- cites [15] Foxe, 1998, Parieto-occipital ∼10 Hz activity reflects anticipatory state of visual attention mechanisms, Neuroreport. source
- cites [16] Kelly, 2006, Increases in alpha oscillatory power reflect an active retinotopic mechanism for distracter suppression during sustained visuospatial attention, J Neurophysiol. source
May combine two claims.
PremisecitationHaskell et al. found improvements in working memory reaction time, sentence verification accuracy, and alertness ratings for combined L-theanine and caffeine but not for either alone.
“Haskell et al. (33) administered a large battery of cognitive tests before and after consumption of a drink containing either placebo, 250 mg of L-theanine, 150 mg of caffeine, or their combination.These authors found improvements in simple and numeric working memory RT, sentence verification accuracy, and alertness ratings for the combined treatment but not for either treatment alone.”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [33] Haskell, 2008, The effects of L-theanine, caffeine and their combination on cognition and mood, Biol Psychol. source
May combine two claims.
PremisecitationParnell et al. found that combined L-theanine and caffeine improved speed and accuracy on an attention-switching task and reduced distractibility in a memory task.
“Parnell et al. (32) reported improved speed and accuracy on an attention-switching task at 60 min and reduced susceptibility to distracting information during a memory task at both 60 and 90 min following ingestion of a combination of L-theanine and caffeine in the same dosages as used here.”
Quote in the paperSubstantial claim0 of 1 sources checked- cites [32] Parnell, 2006, Combined effects of L-theanine and caffeine on cognition and mood, Appetite. source
Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.
PremisecitationRogers et al. found that L-theanine counteracted caffeine's blood pressure rise but did not alter caffeine-induced increases in alertness or jitteriness.
“Using a similar crossover design but with a greater dosage of caffeine (250 mg) than L-theanine (200 mg), Rogers et al. (34) found that L-theanine tended to counteract the caffeine-induced rise in blood pressure but did not interact with caffeine-induced increases in either alertness or ''jitteriness'' on state anxiety scales.”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [34] Rogers, 2008, Time for tea: mood, blood pressure and cognitive performance effects of caffeine and L-theanine administered alone and together, Psychopharmacology (Berl). source
Classified as probably not a substantial claim. May combine two claims.
Study design and conductown dataThe study used a four-day balanced repeated-measures design in which treatment order was counterbalanced across subjects.
“A 4-d balanced repeated-measures design was employed, with subjects receiving 1 of the 4 treatments (including placebo) on each day in counterbalanced order.”
Quote in the paperSubstantial claimClassified as probably not a substantial claim.
Study design and conductown dataParticipants were not told which treatment they received.
“Subjects were uninformed of the treatment, which was served in 100 mL of water, with the placebo treatment consisting only of water.”
Quote in the paperSubstantial claim- Rests on an assumption: L-theanine and caffeine are tasteless when dissolved in water.
Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based).
PremisecitationEarlier work found that tonic alpha amplitude decreased after L-theanine.
“In addition, tonic (background) alpha amplitude was relatively decreased for L-theanine, in apparent contradiction to the findings of Juneja et al. (13).”
Quote in the paperNot a substantial claim0 of 1 sources checked- cites [13] Juneja, 1999, L-Theanine—a unique amino acid of green tea and its relaxation effect in humans, Trends Food Sci Technol. source
Probably not a substantial claim: may not pass S3 (load-bearing).
Study design and conductreasoningA Bonferroni-corrected alpha level of 0.016 was used for the three behavioral t-tests.
“Because 3 t-tests were performed including the same placebo data, we applied a Bonferronicorrected a-level of 0.016 here.”
Quote in the paperNot a substantial claimProbably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.
Study design and conductown dataEEG data were baseline-corrected and artifact-rejected at a threshold of 6100 mV as reported.
“EEG data were epoched from 2300 ms before to 1100 ms after cue onset and baseline-corrected relative to the interval 2100 to 0 ms, with an artifact rejection threshold of 6100 mV applied.”
Quote in the paperNot a substantial claimProbably not a substantial claim: may not pass S3 (load-bearing).
Study design and conductnone givenTrials were discarded if eye gaze moved more than 0.5° during the cue-target interval.
“Based on a calibrated mapping of EOG amplitude to visual angle, trials were rejected off-line if eye gaze deviated by .0.5° during the cue-target interval.”
Quote in the paperNot a substantial claimMay combine two claims.
InterpretationreasoningThe present study is the third report of decreased alpha after L-theanine ingestion, which demonstrates the reliability of this effect.
“This study marks the third finding of decreased alpha as a result of L-theanine ingestion (albeit a partial cause here) to date, demonstrating the reliability of the effect.”
Quote in the paperSubstantial claimClassified as probably not a substantial claim.
Study design and conductown dataThe experiment included a placebo condition.
“Subjects underwent 4 d of testing, ingesting either placebo, 100 mg of L-theanine, 50 mg of caffeine, or these treatments combined.”
Quote in the paperSubstantial claim- Rests on an assumption: L-theanine and caffeine are tasteless when dissolved in water.
Classified as probably not a substantial claim.
PremisecitationIn intersensory attention tasks, parieto-occipital alpha power increases for attend-visual trials compared with attend-auditory trials.
“In intersensory attention tasks, where the relevant modality is cued ;1 s before a compound audiovisual target stimulus, parieto-occipital alpha power in the intervening period is increased for attend-visual trials relative to attend-auditory trials (15,17).”
Quote in the paperSubstantial claim0 of 2 sources checked- cites [15] Foxe, 1998, Parieto-occipital ∼10 Hz activity reflects anticipatory state of visual attention mechanisms, Neuroreport. source
- cites [17] Fu, 2001, Attention-dependent suppression of distracter visual input can be cross-modally cued as indexed by anticipatory parieto-occipital alpha-band oscillations, Brain Res Cogn Brain Res. source
The paper relies on this without support.
A typical serving of tea contains roughly 100 mg L-theanine and 50 mg caffeine.
“An immediate question, given this replication, is whether this tonic alpha reduction occurs at lower dosages of L-theanine, closer to the amount ingested through a typical serving of tea.In the present study, we administered a lower dosage of 100 mg to address this.”
The paper relies on this without support.
L-theanine and caffeine are tasteless when dissolved in water.
“Both theanine and caffeine are tasteless in water solution.”
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In active and anticipatory conditions, theanine reduced alpha power at 100 mg.
“whereas in active and anticipatory conditions, studies have shown that theanine reduced alpha power at 100 mg,62”
From Effects of Tea (<i>Camellia sinensis</i>) or its Bioactive Compounds <scp>l</scp>-Theanine or <scp>l</scp>-Theanine plus Caffeine on Cognition, Sleep, and Mood in Healthy Participants: A Systematic Review and Meta-Analysis of Randomized Controlled Trials (2025) · cites this paper as [62]
The Results (page unavailable) report that 100 mg of L-theanine alone did not significantly lower tonic alpha power or change the anticipatory alpha cueing effect. Lower tonic alpha was found with the combined theanine–caffeine treatment, while the Discussion reports reductions with theanine alone at 250 mg, not 100 mg. (LLM, conf=0.90)
Checked by a reasoning model — may be wrong.
Experimental — accuracy not yet measuredCaffeine improves sustained attention in healthy adults.
“Caffeine has been known for decades to improve sustained attention in healthy adults (e.g. Refs.25–27, animal models with ADHD28 and even individuals with ADHD29,30.”
From Effects of l-theanine–caffeine combination on sustained attention and inhibitory control among children with ADHD: a proof-of-concept neuroimaging RCT (2020) · cites this paper as [25]
The Results (page not provided) report that caffeine alone improved target discriminability in neurologically normal adults, but did not significantly improve hit rate or reaction time. The Methods describe a cued visuospatial attention task, not a specific test of sustained attention, so the sustained-attention claim is broader than the reported finding. (LLM, conf=0.82)
Experimental — accuracy not yet measuredThe lack of positive behavioural effects of the combination is contrary to previous findings.
“This is contrary to previous findings (Einother et al. 2010; Haskell et al. 2008; Kelly et al. 2008; Owen et al. 2008)”
From A Double-Blind, Placebo-Controlled Study Evaluating the Effects of Caffeine and L-Theanine Both Alone and in Combination on Cerebral Blood Flow, Cognition and Mood (2015) · cites this paper as Kelly et al. 2008
Individual studies suggest that co-ingestion of caffeine and L-theanine may have an additive effect, with additional benefits compared to each administered in isolation, though findings are inconsistent.
“Individual studies have, however, suggested that co-ingestion of caffeine and L-theanine may have an additive effect, with additional benefits noted compared to when each is administered in isolation (20–27), although such findings have been somewhat inconsistent (28, 29) and would benefit from further behavioral and mechanistic evaluation.”
From Effects of L-theanine on cognition, mood and sleep: evidence from human trials (2026) · cites this paper as [24]
Improvements in cognitive performance, subject alertness and complex senses interactions have been documented following L-THE consumption.
“Likewise, improvements in cognitive performance, subject alertness and complex senses interactions have also been documented [62][63][64].”
From l-Theanine as a Functional Food Additive: Its Role in Disease Prevention and Health Promotion (2016) · cites this paper as [62]
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“L-Theanine (g-glutamylethylamide), a unique amino acid present almost exclusively in the tea plant, has recently received research interest in the neuroscience community with findings of neuroprotective effects [see Kakuda (9)] and mood effects indexed both by subjective self-reports (10) and via psychological and phy…”
BackgroundKuriyama, S. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1548s · Cited by 150 · see citing works
Targeting Multiple Neurodegenerative Diseases Etiologies with Multimodal-Acting Green Tea Catechins
Mandel, S. A., Amit, T., Kalfon, L., Reznichenko, L., & Youdim, M. B. H. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1578s · Cited by 148 · see citing works
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Bioavailability of Polyphenon E Flavan-3-ols in Humans with an Ileostomy4
Auger, C., Mullen, W., Hara, Y., & Crozier, A. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1535s · Cited by 131 · see citing works
Dockree, P. M., Kelly, S. P., Foxe, J. J., Reilly, R. B., & Robertson, I. H. (2007) · European Journal of Neuroscience · doi:10.1111/j.1460-9568.2007.05324.x · Cited by 126 · see citing works
Self-citationEffects of L-Theanine on the Release of .ALPHA.-Brain Waves in Human Volunteers.
KOBAYASHI, K., NAGATO, Y., AOI, N., JUNEJA, L. R., KIM, M., YAMAMOTO, T., & SUGIMOTO, S. (1998) · Journal of the agricultural chemical society of Japan · doi:10.1271/nogeikagaku1924.72.153 · Cited by 123 · see citing works
A Review of the Epidemiological Evidence on Tea, Flavonoids, and Lung Cancer2
Arts, I. C. W. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1561s · Cited by 122 · see citing works
TERASHIMA, T., TAKIDO, J., & YOKOGOSHI, H. (1999) · Bioscience, Biotechnology, and Biochemistry · doi:10.1271/bbb.63.615 · Cited by 112 · see citing works
Tea Is the Major Source of Flavan-3-ol and Flavonol in the U.S. Diet
Song, W. O., & Chun, O. K. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1543s · Cited by 101 · see citing works
Nongallated Compared with Gallated Flavan-3-ols in Green and Black Tea Are More Bioavailable
Henning, S. M., Choo, J. J., & Heber, D. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1529s · Cited by 98 · see citing works
Tea, Flavonoids, and Nitric Oxide-Mediated Vascular Reactivity
Grassi, D., Aggio, A., Onori, L., Croce, G., Tiberti, S., Ferri, C., Ferri, L., & Desideri, G. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1554s · Cited by 98 · see citing works
Gomez-Ramirez, M., Higgins, B. A., Rycroft, J. A., Owen, G. N., Mahoney, J., Shpaner, M., & Foxe, J. J. (2007) · Clinical Neuropharmacology · doi:10.1097/01.wnf.0000240940.13876.17 · Cited by 96 · see citing works
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Effects of caffeine on topographic quantitative EEG
Siepmann, M., & Kirch, W. (2002) · Neuropsychobiology · doi:10.1159/000054958 · Cited by 85 · see citing works
Electroencephalographic correlates of marihuana-induced euphoria
Lukas, S. E., Mendelson, J. H., & Benedikt, R. A. (1995) · Drug and Alcohol Dependence · doi:10.1016/0376-8716(94)01067-u · Cited by 76 · see citing works
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Hakim, I. A., Chow, H. ‐. S., & Harris, R. B. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1567s · Cited by 49 · see citing works
Tea Consumption May Improve Biomarkers of Insulin Sensitivity and Risk Factors for Diabetes
Stote, K. S., & Baer, D. J. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1584s · Cited by 49 · see citing works
Blumberg, J. B. (2003) · Journal of Nutrition · doi:10.1093/jn/133.10.3244s · Cited by 32 · see citing works
Arab, L., & Blumberg, J. B. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1526s · Cited by 21 · see citing works
Corrigendum to “L-theanine—a unique amino acid of green tea and its relaxation effect in humans”
Juneja, L. R., Chu, D., Ōkubo, T., Nagato, Y., & Yokogoshi, H. (1999) · Trends in Food Science & Technology · doi:10.1016/s0924-2244(00)00031-5 · Cited by 20 · see citing works
Combined effects of L-theanine and caffeine on cognition and mood
Parnell, H., Owen, G. N., & Rycroft, J. A. (2006) · Appetite · doi:10.1016/j.appet.2006.07.051 · Cited by 9 · see citing works
The effects of caffeine on the topographical quantitative EEG
Siepmann, M. (2001) · NeuroImage · doi:10.1016/s1053-8119(01)91702-1
Steptoe, A., Gibson, E. L., Vuononvirta, R., et al. (2007) · Psychopharmacology · doi:10.1007/s00213-006-0620-z
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EEG frequency bands in psychiatric disorders: a review of resting state studies
Newson, J. J., & Thiagarajan, T. C. (2019) · Frontiers in Human Neuroscience · doi:10.3389/fnhum.2018.00521 · Cited by 863 · see citing works
Saeed, M., Naveed, M., Arif, M. A., Kakar, M. U., Manzoor, R., El-Hack, M. E. A., Alagawany, M. M., Tiwari, R., Khandia, R., Munjal, A. K., et al. (2017) · Biomedicine & Pharmacotherapy · doi:10.1016/j.biopha.2017.09.024 · Cited by 246 · see citing works
Bioactive components of tea: Cancer, inflammation and behavior
de Mejı́a, E. G., Ramı́rez-Mares, M. V., & Puangpraphant, S. (2009) · Brain Behavior and Immunity · doi:10.1016/j.bbi.2009.02.013 · Cited by 232 · see citing works
“Matching electroencephalographic recordings with cognitive task performance, it has been demonstrated that the unique tea amino acid theanine plays a role in attentional processing, in synergy with caffeine, enhancing cognition in humans (Kelly et al., 2008).”
Caffeine as an Attention Enhancer: Reviewing Existing Assumptions
Einöther, S. J. L., & Giesbrecht, T. (2013) · Psychopharmacology · doi:10.1007/s00213-012-2917-4 · Cited by 215 · see citing works
Green tea effects on cognition, mood and human brain function: A systematic review
Mancini, E., Beglinger, C., Drewe, J., Zanchi, D., Lang, U. E., & Borgwardt, S. (2017) · Phytomedicine · doi:10.1016/j.phymed.2017.07.008 · Cited by 224 · see citing works
“L-Theanine Ten experimental studies (Einother et al., 2010; Giesbrecht et al., 2010; Haskell et al., 2008; Kelly et al., 2008; Kimura et al., 2007; Ota et al., 2014; Owen et al., 2008; Park et al., 2011; Ritsner et al., 2011; Yoto et al., 2012) focussed on the effects of L-theanine intake.”
BackgroundResultInfluentialL-Theanine, Unique Amino Acid of Tea, and Its Metabolism, Health Effects, and Safety
Türközü, D., & Şanlier, N. (2017) · Critical Reviews in Food Science and Nutrition · doi:10.1080/10408398.2015.1016141 · Cited by 207 · see citing works
“caffeine in increasing the attention process and cognitive performance in humans (Kelly et al., 2008).”
BackgroundKelly, S. P., Gomez‐Ramirez, M., & Foxe, J. J. (2009) · European Journal of Neuroscience · doi:10.1111/j.1460-9568.2009.06980.x · Cited by 188 · see citing works
“…Treatment on the broadband indices (all P > 0.1), there was a main effect of Treatment on alpha (F3,36 = 3.50, P 0.05), reflecting the reduction of tonic alpha, but not spatially-selective alpha biasing, on ingestion of both theanine and caffeine as described previously (Kelly et al., 2008).”
BackgroundInfluentialSelf-citationBanerjee, S., Snyder, A. C., Molholm, S., & Foxe, J. J. (2011) · Journal of Neuroscience · doi:10.1523/jneurosci.4660-10.2011 · Cited by 193 · see citing works
“The regions of interest chosen for testing were based on scalp topographies in existing studies (Worden et al., 2000; Kelly et al., 2008) with electrode clusters over left and right parieto-occipital scalp.”
MethodSelf-citationPhytochemicals and cognitive health: Are flavonoids doing the trick?
Bakoyiannis, I., Daskalopoulou, A., Pergialiotis, V., & Perrea, D. N. (2018) · Biomedicine & Pharmacotherapy · doi:10.1016/j.biopha.2018.10.086 · Cited by 186 · see citing works
Acute neurocognitive effects of epigallocatechin gallate (EGCG)
Scholey, A. B., Downey, L. A., Ciorciari, J., Pipingas, A., Nolidin, K., Finn, M., Wines, M., Catchlove, S. J., Terrens, A., Barlow, E., et al. (2011) · Appetite · doi:10.1016/j.appet.2011.11.016 · Cited by 150 · see citing works
“…black tea consumption has shown that the amino acid theanine (c-N-ethylglutamine) alters brain activity associated with attentional functioning (Kelly et al., 2008) and increases feelings of calmness and relaxation (Nobre et al., 2008) similar to the current findings relating to acute EGCG…”
Targeting Multiple Neurodegenerative Diseases Etiologies with Multimodal-Acting Green Tea Catechins
Mandel, S. A., Amit, T., Kalfon, L., Reznichenko, L., & Youdim, M. B. H. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1578s · Cited by 148 · see citing works
Kuriyama, S. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1548s · Cited by 150 · see citing works
Camfield, D. A., Stough, C., Farrimond, J., & Scholey, A. B. (2014) · Nutrition Reviews · doi:10.1111/nure.12120 · Cited by 141 · see citing works
Kerr, C. E., Jones, S. R., Wan, Q., Pritchett, D. L., Wasserman, R. H., Wexler, A., Villanueva, J. J., Shaw, J. R., Lazar, S. W., Kaptchuk, T. J., et al. (2011) · Brain Research Bulletin · doi:10.1016/j.brainresbull.2011.03.026 · Cited by 140 · see citing works
Bioavailability of Polyphenon E Flavan-3-ols in Humans with an Ileostomy4
Auger, C., Mullen, W., Hara, Y., & Crozier, A. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1535s · Cited by 131 · see citing works
A Review of the Epidemiological Evidence on Tea, Flavonoids, and Lung Cancer2
Arts, I. C. W. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1561s · Cited by 122 · see citing works
Foxe, J. J., Morie, K. P., Laud, P. J., Rowson, M. J., de Bruin, E. A., & Kelly, S. P. (2012) · Neuropharmacology · doi:10.1016/j.neuropharm.2012.01.020 · Cited by 106 · see citing works
“In a series of studies from this laboratory, a clear link between theanine ingestion and alpha-band oscillatory brain activity during demanding selective attention tasks has been established (GomezRamirez et al., 2007, 2009; Kelly et al., 2008).”
BackgroundMethodResultInfluentialSelf-citationPark, S.-K., Jung, I.-C., Lee, W. K., Lee, Y. S., Park, H. K., Go, H. J., Kim, K., Lim, N. K., Hong, J. T., Ly, S. Y., et al. (2011) · Journal of Medicinal Food · doi:10.1089/jmf.2009.1374 · Cited by 105 · see citing works
“the hit rate of attention tasks using a cathode ray tube monitor, which indicates an improvement in the subject’s attention.(37) However, there have been no interventional studies using a combination treatment of GTE and l-theanine and assessing cognitive performance.”
The combined effects of L-theanine and caffeine on cognitive performance and mood
Owen, G. N., Parnell, H., De Bruin, E. A., & Rycroft, J. A. (2008) · Nutritional Neuroscience · doi:10.1179/147683008x301513 · Cited by 103 · see citing works
Giesbrecht, T., Rycroft, J. A., Rowson, M. J., & De Bruin, E. A. (2010) · Nutritional Neuroscience · doi:10.1179/147683010x12611460764840 · Cited by 102 · see citing works
Tea Is the Major Source of Flavan-3-ol and Flavonol in the U.S. Diet
Song, W. O., & Chun, O. K. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1543s · Cited by 101 · see citing works
Dodd, F. L., Kennedy, D. O., Riby, L. M., & Haskell-Ramsay, C. F. (2015) · Psychopharmacology · doi:10.1007/s00213-015-3895-0 · Cited by 100 · see citing works
“…al. 2008; Owen et al. 2008), providing support for the findings from studies of higher doses, in terms of improved accuracy (Einother et al. 2010; Kelly et al. 2008; Owen et al. 2008) and speed (Einother et al. 2010; Owen et al. 2008) on tasks of attention, and improvements to measures of memory…”
BackgroundResultInfluentialArab, L., Biggs, M. L., O'Meara, E. S., Longstreth, W. T., Crane, P. K., & Fitzpatrick, A. L. (2011) · Journal of Alzheimer's Disease · doi:10.3233/jad-2011-110431 · Cited by 98 · see citing works
Tea, Flavonoids, and Nitric Oxide-Mediated Vascular Reactivity
Grassi, D., Aggio, A., Onori, L., Croce, G., Tiberti, S., Ferri, C., Ferri, L., & Desideri, G. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1554s · Cited by 98 · see citing works
Nongallated Compared with Gallated Flavan-3-ols in Green and Black Tea Are More Bioavailable
Henning, S. M., Choo, J. J., & Heber, D. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1529s · Cited by 98 · see citing works
Gomez-Ramirez, M., Kelly, S. P., Montesi, J. L., & Foxe, J. J. (2009) · Brain Topography · doi:10.1007/s10548-008-0068-z · Cited by 87 · see citing works
“More recent research has shown that alpha activity is not simply associated with brain arousal states but indexes the operation of selective attention mechanisms (Vanni et al. 1997; Foxe et al. 1998; Worden et al. 2000; Fu et al. 2001; Bastiaansen and Brunia 2001; Bastiaansen et al. 2001; Kelly et al. 2005; Yamagishi…”
BackgroundSelf-citationWilliams, J., Sergi, D., McKune, A. J., Georgousopoulou, E. N., Mellor, D. D., & Naumovski, N. (2019) · Phytotherapy Research · doi:10.1002/ptr.6277 · Cited by 73 · see citing works
Acute effects of tea consumption on attention and mood
Einöther, S. J. L., & Martens, V. E. G. (2013) · American Journal of Clinical Nutrition · doi:10.3945/ajcn.113.058248 · Cited by 74 · see citing works
“This combination improved speed and accuracy on a range of tasks from the Cognitive Drug Research test battery (46), improved accuracy on an attention-switching test (47–49), improved accuracy on a cued attention test (50), and improved accuracy on a sustained attention test (51).”
BackgroundThangarajan, S., Deivasigamani, A., Natarajan, S. S., Krishnan, P., & Mohanan, S. K. (2014) · International Journal of Neuroscience · doi:10.3109/00207454.2013.872642 · Cited by 71 · see citing works
Acute Effects of Theanine, Caffeine and Theanine–Caffeine Combination on Attention
Kahathuduwa, C. N., Dassanayake, T. L., Amarakoon, A. M. T., & Weerasinghe, V. S. (2017) · Nutritional Neuroscience · doi:10.1080/1028415x.2016.1144845 · Cited by 70 · see citing works
Effect of Green Tea Phytochemicals on Mood and Cognition
Dietz, C., & Dekker, M. (2017) · Current Pharmaceutical Design · doi:10.2174/1381612823666170105151800 · Cited by 70 · see citing works
Theanine and caffeine content of infusions prepared from commercial tea samples
Csupor, D., Boros, K., & Jedlinszki, N. (2016) · Pharmacognosy Magazine · doi:10.4103/0973-1296.176061 · Cited by 68 · see citing works
“Moreover, together with caffeine, L‐theanine has a synergistic positive effect on attention as demonstrated in human electroencephalography studies,[7] and in a behavioral study.”
BackgroundHuman disposition of L-theanine in tea or aqueous solution
van der Pijl, P. C., Chen, L., & Mulder, T. P. J. (2010) · Journal of Functional Foods · doi:10.1016/j.jff.2010.08.001 · Cited by 66 · see citing works
“…of distribution over the absolute bioavailability available at www.sciencedirect.com journal homepage: www.elsevier.com/locate/jff EEG studies between 30 and 120 min (Kelly et al., 2008), and in a behavioural study after 60 min following L-theanine plus caffeine consumption (Owen et al., 2008).”
Lee, J.-H., & Chambers, D. H. (2010) · Journal of Food Science · doi:10.1111/j.1750-3841.2009.01503.x · Cited by 66 · see citing works
Dietz, C., Dekker, M., & Piqueras‐Fiszman, B. (2017) · Food Research International · doi:10.1016/j.foodres.2017.05.002 · Cited by 68 · see citing works
Einöther, S. J. L., Martens, V. E. G., Rycroft, J. A., & De Bruin, E. A. (2010) · Appetite · doi:10.1016/j.appet.2010.01.003 · Cited by 62 · see citing works
“Previous studies which included L -theanine and/or caffeine in isolation (Haskell et al., 2008; Kelly et al., 2008; Owen et al., 2008) indicated that the L -theanine/caffeine combination had synergistic effects.”
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Plant-derived nootropics and human cognition: A systematic review
Lorca, C., Mulet, M., Arévalo‐Caro, C., Sanchez, M. Á., Perez, A., Perrino, M., Bach-Faig, A., Aguilar, A., Vilella, E., Gallart‐Palau, X., et al. (2022) · Critical Reviews in Food Science and Nutrition · doi:10.1080/10408398.2021.2021137 · Cited by 64 · see citing works
Schuster, J., & Mitchell, E. S. (2018) · Progress in Neuro-Psychopharmacology and Biological Psychiatry · doi:10.1016/j.pnpbp.2018.09.005 · Cited by 58 · see citing works
Black tea improves attention and self-reported alertness
De Bruin, E. A., Rowson, M. J., Van Buren, L., Rycroft, J. A., & Owen, G. N. (2011) · Appetite · doi:10.1016/j.appet.2010.12.011 · Cited by 54 · see citing works
Diabetes and Alzheimer’s Disease: Can Tea Phytochemicals Play a Role in Prevention?
Fernando, W. M. A. D. B., Somaratne, G., Goozee, K. G., Williams, S., Singh, H., & Martins, R. N. (2017) · Journal of Alzheimer s Disease · doi:10.3233/jad-161200 · Cited by 55 · see citing works
“In response to earlier positive reports of the effects of L-theanine on attention-related task performance [159], further literature emerged.”
BackgroundAcute effects of dietary constituents on motor skill and cognitive performance in athletes
Baker, L. B., Nuccio, R. P., & Jeukendrup, A. E. (2014) · Nutrition Reviews · doi:10.1111/nure.12157 · Cited by 57 · see citing works
l-Theanine as a Functional Food Additive: Its Role in Disease Prevention and Health Promotion
Williams, J., Kellett, J., Roach, P., McKune, A., Mellor, D., Thomas, J., & Naumovski, N. (2016) · Beverages · doi:10.3390/beverages2020013 · Cited by 52 · see citing works
“Likewise, improvements in cognitive performance, subject alertness and complex senses interactions have also been documented [62–64].”
BackgroundEffects of l-theanine on attention and reaction time response
Higashiyama, A., Htay, H. H., Ozeki, M., Juneja, L. R., & Kapoor, M. P. (2011) · Journal of Functional Foods · doi:10.1016/j.jff.2011.03.009 · Cited by 50 · see citing works
Hakim, I. A., Chow, H. ‐. S., & Harris, R. B. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1567s · Cited by 49 · see citing works
Tea Consumption May Improve Biomarkers of Insulin Sensitivity and Risk Factors for Diabetes
Stote, K. S., & Baer, D. J. (2008) · Journal of Nutrition · doi:10.1093/jn/138.8.1584s · Cited by 49 · see citing works
Influence of energy drink ingredients on mood and cognitive performance
Childs, E. (2014) · Nutrition Reviews · doi:10.1111/nure.12148 · Cited by 49 · see citing works
Takeda, A., Sakamoto, K., Tamano, H., Fukura, K., Inui, N., Suh, S. W., Won, S.-J., & Yokogoshi, H. (2011) · Cellular and Molecular Neurobiology · doi:10.1007/s10571-011-9707-0 · Cited by 46 · see citing works
“The combination of theanine and caffeine enhances cognitive function in humans (Haskell et al. 2008; Kelly et al. 2008; Einöther et al. 2010).”
BackgroundEffects of a single, oral 60 mg caffeine dose on attention in healthy adult subjects
Wilhelmus, M. M. M., Hay, J. L., Zuiker, R. G. J. A., Okkerse, P., Perdrieu, C., Sauser, J., Beaumont, M., Schmitt, J. A. J., van Gerven, J. M., & Silber, B. Y. (2016) · Journal of Psychopharmacology · doi:10.1177/0269881116668593 · Cited by 46 · see citing works
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Tea and health: preventive and therapeutic usefulness in the elderly?
Bolling, B. W., Chen, C.-Y. O., & Blumberg, J. B. (2008) · Current Opinion in Clinical Nutrition & Metabolic Care · doi:10.1097/mco.0b013e32831b9c48 · Cited by 43 · see citing works
Relationships between tea and other beverage consumption to work performance and mood
Bryan, J., Tuckey, M. R., Einöther, S. J. L., Garczarek, U., Garrick, A., & de Bruin, E. A. (2011) · Appetite · doi:10.1016/j.appet.2011.11.009 · Cited by 44 · see citing works
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The effects of twenty-one nutrients and phytonutrients on cognitive function: A narrative review
Lewis, J. E., Poles, J., Shaw, D. P., Karhu, E., Khan, S. A., Lyons, A. E., Sacco, S. B., & McDaniel, H. R. (2021) · Journal of Clinical and Translational Research · doi:10.18053/jctres.07.202104.014 · Cited by 37 · see citing works
“When ingested alone, theanine has been found to induce calmness and synchronicity of brain activity [252], but when combined with caffeine it induces even greater synchronization [253], providing improvements in attention [254].”
BackgroundBaba, Y., Inagaki, S., Nakagawa, S., Kobayashi, M., Kaneko, T., & Takihara, T. (2021) · Nutrients · doi:10.3390/nu13051700 · Cited by 33 · see citing works
Stuck at the bench: Potential natural neuroprotective compounds for concussion
Petraglia, A. L., Bailes, J., & Winkler, E. (2011) · Surgical Neurology International · doi:10.4103/2152-7806.85987 · Cited by 33 · see citing works
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Caffeine and theanine exert opposite effects on attention under emotional arousal
Giles, G. E., Mahoney, C. R., Brunyé, T. T., Taylor, H. A., & Kanarek, R. B. (2016) · Canadian Journal of Physiology and Pharmacology · doi:10.1139/cjpp-2016-0498 · Cited by 26 · see citing works
“4 in that 35-50 mg caffeine and 90-100 mg theanine enhanced mental alertness, task switching attention, and recognition memory relative to placebo (Einother et al. 2010a; Giesbrecht et al. 2010; Kelly et al. 2008; Owen et al. 2008).”
InfluentialHan, Z., Wang, L., Zhu, H., Tu, Y., He, P., & Li, B. (2024) · Food Research International · doi:10.1016/j.foodres.2024.115191 · Cited by 27 · see citing works
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“…studied due to its beneficial properties for human health, since it interacts with diverse physiological and biochemical pathways, e.g. it elicits significant effects on the general state of mental alertness by increasing 𝛼 -wave brain activity and the reduction of anxiety ( Kelly et al., 2008 ).”
BackgroundTakeda, A., Tamano, H., Suzuki, M., Sakamoto, K., Oku, N., & Yokogoshi, H. (2012) · Cellular and Molecular Neurobiology · doi:10.1007/s10571-011-9732-z · Cited by 25 · see citing works
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“Extending this experimental work to human studies, Foxe and his colleagues (22) have matched electroencephalographic recordings with cognitive task performance to demonstrate that the unique tea amino acid L-theanine (g-glutamylethylamide) plays a role in attentional processing in synergy with caffeine.”
BackgroundYilmaz, U., Buzdagli, Y., Polat, M. L., Bakir, Y., Ozhanci, B., Alkazan, S., & Ucar, H. (2023) · Journal of the International Society of Sports Nutrition · doi:10.1080/15502783.2023.2267536 · Cited by 19 · see citing works
“In terms of cognitive function, there are studies in the literature that suggest THE may cause performance decrements when administered single [62,68] or have no effect [69,70].”
BackgroundAdvantageous effect of theanine intake on cognition
Tamano, H., Fukura, K., Suzuki, M., Sakamoto, K., Yokogoshi, H., & Takeda, A. (2014) · Nutritional Neuroscience · doi:10.1179/1476830513y.0000000094 · Cited by 19 · see citing works
Behavioural effects of compounds co-consumed in dietary forms of caffeinated plants
Haskell‐Ramsay, C. F., Dodd, F. L., Wightman, E. L., & Kennedy, D. O. (2013) · Nutrition Research Reviews · doi:10.1017/s0954422413000036 · Cited by 17 · see citing works
“A combination of 100 mg L-theanine and 50 mg caffeine was also capable of improving performance accuracy (as measured by increased hit rate and target discriminability) and reducing overall tonic (background) alpha power((143)), as well as simultaneously improving speed and accuracy on an attention-switching task at 6…”
Habitual tea drinking modulates brain efficiency: evidence from brain connectivity evaluation
Li, J., Romero-García, R., John Suckling, A., & Feng, L. (2019) · Aging · doi:10.18632/aging.102023 · Cited by 17 · see citing works
“Although individual constituents of tea have been related to the roles of maintaining cognitive abilities and preventing cognitive decline, a study with behavioural and neurophysiological measures showed that there was a degraded effect or no effect when a constituent was administered alone and a significant effect wa…”
Dassanayake, T. L., Kahathuduwa, C. N., & Weerasinghe, V. S. (2022) · Nutritional Neuroscience · doi:10.1080/1028415x.2020.1804098 · Cited by 16 · see citing works
“tion tasks employed by some previous researchers [25,26].”
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“…with mind wandering—also termed spontaneous thought 83 —and 1 study found positive effects of 100 mg theanine on behavioral cognition outcomes, 52 although 2 other studies found no effect, 55,62 and 1 study showed an effect in favor of placebo compared to theanine, 54 using doses ≥ 100 mg.”
Methylphenidate as a causal test of translational and basic neural coding hypotheses
Ni, A. M., Bowes, B., Ruff, D. A., & Cohen, M. R. (2022) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.2120529119 · Cited by 13 · see citing works
“Prior studies that have measured how stimulants affect hit rate versus false alarm rate suggest that different stimulants and dosages can have distinct effects on sensitivity versus criterion (43, 44).”
BackgroundDassanayake, T. L., Wijesundara, D., Kahathuduwa, C. N., & Weerasinghe, V. S. (2023) · Nutritional Neuroscience · doi:10.1080/1028415x.2022.2136884 · Cited by 14 · see citing works
“How L-theanine modi fi es perceptual processing in the cerebral neural circuits and enable attentional fi ltering is not well de fi ned, but few EEG [17, 21, 24] and fMRI [26, 27] studies point toward plausible mechanisms.”
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“Potential cognitive benefits of combining L-theanine and caffeine ([108]).”
BackgroundMedrano, M., Molina‐Hidalgo, C., Alcántara, J. M. A., Ruiz, J. R., & Jurado‐Fasoli, L. (2022) · Frontiers in Nutrition · doi:10.3389/fnut.2022.858910 · Cited by 10 · see citing works
“Previous studies have shown that supplementation with caffeine (38), the combination of caffeine and taurine (34), caffeine and L-theanine (39), tyrosine (40), and mango leaves extract (41) can improve the RT in different cognitive and computerized tests.”
BackgroundInfluentialThe effects of caffeine on option generation and subsequent choice
Häusser, J. A., Schlemmer, A., Kaiser, S., Kalis, A., & Mojzisch, A. (2014) · Psychopharmacology · doi:10.1007/s00213-014-3506-5 · Cited by 10 · see citing works
The effect of black tea on human cognitive performance in a cognitive test battery
Rizwan, A., Zinchenko, A., Özdem, C., Rana, M. S., & Al-Amin, M. M. (2017) · Clinical Phytoscience · doi:10.1186/s40816-017-0049-4 · Cited by 10 · see citing works
“We used a lower amount of BT since several studies suggeste BT does not influence certain cognitive functions [28], particularly at the dosage of less than 100 mg [22, 23].”
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“Although, it was also found in few studies that both theanine and caffeine exhibit synergistic effects at lower doses.([7,8]) There is no doubt that these major constituents of tea (catechins, caffeine, and theanine) are the main bioactive constituents responsible for numerous health beneficial properties of tea.”
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Caffeinated Beverages, Behavior, and Brain Structure
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MethodDrinking tea improves the convergent creativity performance
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“, 2010) and two did not report on between-group statistical comparisons for the caffeine plus L-theanine vs the caffeine interventions (Haskell et al., 2008; Kelly et al., 2008).”
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“L-theanine, a typical amino-acid of green tea has been widely studied due to its beneficial properties for humans, as it interacts in diverse physiological and biochemical pathways: among others, L-theanine has been shown to elicit a significant effect on the general state of mental alertness by increasing α-wave brai…”
Background
- Authors
- Kelly, S. P., Gomez-Ramirez, M., Montesi, J. L., & Foxe, J. J.
- Affiliations
- Nathan Kline Institute for Psychiatric Research (US)
- Corresponding author
- Foxe, John J.
- Venue
- The Journal of Nutrition
- Publisher
- Elsevier BV
- Published
- 2008-08
- Volume
- 138
- Issue
- 8
- Pages
- 1572S-1577S
- ISSN
- 0022-3166 (ISSN-L)
- OpenAlex
- W1955323883
- Semantic Scholar
- e5aa9a2bad9f3c3193ccf2cfe466cfbff42c9594
- Cited by
- 120
- References
- 44
- Citations by year
- 2026: 5 · 2025: 5 · 2024: 4 · 2023: 4 · 2022: 5 · 2021: 8 · 2020: 5 · 2019: 5 · 2018: 4 · 2017: 9 · 2016: 10 · 2015: 2 · 2014: 10 · 2013: 6 · 2012: 3
- FWCI
- 6.72
- Type
- journal article
- Language
- en
- Open access
- bronze
- doi.org
- Licence
- Locations
- Journal of Nutrition (publishedVersion)
- PubMed (publishedVersion)
- Topics
- Health Sciences › Medicine › Pathology and Forensic Medicine › Tea Polyphenols and Effects
- Life Sciences › Neuroscience › Sensory Systems › Olfactory and Sensory Function Studies
- Health Sciences › Medicine › Complementary and alternative medicine › Medicinal Plant Extracts Effects
- Keywords
- theanine, caffeine, tea constituents, visuospatial attention, alpha activity, anticipatory attention, attentional deployment, combination supplementation
- MeSH terms
- Adult, Central Nervous System Stimulants, Attention, Brain Mapping, Caffeine, Cognition, Cues
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