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Study Title and Description

Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together.



Key Questions Addressed
1 For [population], is caffeine intake above [exposure dose], compared to intakes [exposure dose] or less, associated with adverse effects on behavior*?
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Primary Publication Information
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TitleData
Title Time for tea: mood, blood pressure and cognitive performance effects of caffeine and theanine administered alone and together.
Author PJ Rogers,JE Smith,SV Heatherley,CW Pleydell-Pearce,
Country
Year 2008
Numbers

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Extraction Form: Behavior - Design Details - INCLUDED Studies
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Design Details
Question... Follow Up Answer Follow-up Answer
Refid 17891480
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What outcome is being evaluated in this paper? Behavior
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What is the objective of the study (as reported by the authors)? Per the authors, the objective of the study was to evaluate the subjective, behavioral and blood pressure effects of theanine and caffeine administered alone and together, in doses relevant to the daily tea consumption of regular tea drinkers.
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Provide a general description of the methods as reported by the authors. Information should be extracted based on relevance to the SR (i.e., caffeine related methods) Subjects: According to the authors’ description, forty-eight healthy, young adults (age 18-28 years) took part in the study. They were students recruited via print and email advertisements. The study was described as an investigation into the effects of tea on mood. They read an information sheet which outlined the study and stated that they would be asked to consume constituents of tea (caffeine and theanine were not mentioned explicitly). STUDY DESIGN: The study employed a between-subjects design; participants received either caffeine with a theanine placebo, theanine with a caffeine placebo, caffeine together with theanine or caffeine placebo with theanine placebo. Twelve of each of these four treatments were prepared and allocated to participants randomly (without replacement). Treatments were administered double blind. Each participant received a capsule and a 200-ml drink. The capsule contained 250 mg of caffeine or cornflour (caffeine placebo). The drinks contained 200 mg of theanine or no theanine (theanine placebo) and were kept at room temperature and served in a clear glass. They had a peach flavor, but contained no tea constituents, other than theanine as necessary. The placebo- and theanine-containing drinks were not perceptibly different in appearance or taste. Measure of mood, alertness and physical symptoms questionnaire (MAPS): This questionnaire consisted of seven unipolar and four bipolar ten-point scales (0–9) adapted from a similar questionnaire used in previous research on caffeine (e.g. Rogers et al. 2005). ‘Headache’, ‘heart pounding’, ‘jittery/shaky’, ‘light-headed/feeling faint/dizzy’, ‘hands trembling’, ‘scared’, and ‘feeling hot/sweating (not due to heat)’ were rated on unipolar scales labelled ‘I don’t have this feeling at all’ (left-hand end=0) and ‘I have this feeling very strongly’ (right-hand end=9). The bipolar scales were relaxed (labelled ‘anxious/tense/nervous/on edge’=0 and ‘relaxed/calm’=9), clearheaded (labelled ‘muzzy/dazed’=0 and ‘clearheaded’=9), happy (labelled ‘sad/gloomy/miserable’=0 and ‘happy/cheerful/light-hearted’=9) and alert (labelled ‘drowsy, sluggish, tired, fatigued’=0 and ‘alert/energetic/lively’=9). Instructions asked participants to rate ‘how you feel RIGHT NOW’. Mood, alertness and physical symptoms questionnaire (MAPS) This paper questionnaire consisted of seven unipolar and four bipolar ten-point scales (0–9) adapted from a similar questionnaire used in previous research on caffeine (e.g. Rogers et al. 2005). ‘Headache’, ‘heart pounding’, ‘jittery/shaky’, ‘light-headed/feeling faint/dizzy’, ‘hands trembling’, ‘scared’, and ‘feeling hot/sweating (not due to heat)’ were rated on unipolar scales labelled ‘I don’t have this feeling at all’ (left-hand end=0) and ‘I have this feeling very strongly’ (right-hand end=9). The bipolar scales were relaxed (labelled ‘anxious/tense/nervous/on edge’=0 and ‘relaxed/calm’=9), clearheaded (labelled ‘muzzy/dazed’=0 and ‘clearheaded’=9), happy (labelled ‘sad/gloomy/miserable’=0 and ‘happy/cheerful/light-hearted’=9) and alert (labelled ‘drowsy, sluggish, tired, fatigued’=0 and ‘alert/energetic/lively’=9). Participants were asked to rate ‘how you feel RIGHT NOW’. Mood, alertness and physical symptoms questionnaire (MAPS) This paper questionnaire consisted of seven unipolar and four bipolar ten-point scales (0–9) adapted from a similar questionnaire used in previous research on caffeine (e.g. Rogers et al. 2005). ‘Headache’, ‘heart pounding’, ‘jittery/shaky’, ‘light-headed/feeling faint/dizzy’, ‘hands trembling’, ‘scared’, and ‘feeling hot/sweating (not due to heat)’ were rated on unipolar scales labelled ‘I don’t have this feeling at all’ (left-hand end=0) and ‘I have this feeling very strongly’ (right-hand end=9). The bipolar scales were relaxed (labelled ‘anxious/tense/nervous/on edge’=0 and ‘relaxed/calm’=9), clearheaded (labelled ‘muzzy/dazed’=0 and ‘clearheaded’=9), happy (labelled ‘sad/gloomy/miserable’=0 and ‘happy/cheerful/light-hearted’=9) and alert (labelled ‘drowsy, sluggish, tired, fatigued’=0 and ‘alert/energetic/lively’=9). Instructions asked participants to rate ‘how you feel RIGHT NOW’. Statistical Analysis: Post-treatment data for MAPS and blood pressure were analyzed using analysis of covariance with caffeine (caffeine/placebo) and theanine (theanine/placebo) and computer-task order (visual probe task first/facial expression recognition task first) as between-subjects factors and pre-treatment (baseline) data for the measure as the covariate.
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How many outcome-specific endpoints are evaluated? 4
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What is the (or one of the) endpoint(s) evaluated? (Each endpoint listed separately) Anxiety
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List additional health endpoints (separately).
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List additional health endpoints (separately)
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Notes other endpoints measured included bi-polar scales of mood relaxed, clearheaded, happy, alert
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Clinical Clinical
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Physiological
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Other
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What is the study design? Controlled Trial
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Randomized or Non-Randomized? RCT
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What were the diagnostics or methods used to measure the outcome? Subjective
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Optional: Name of Method or short description Mood, alertness and physical symptoms questionnaire (MAPS) This paper questionnaire consisted of seven unipolar and four bipolar ten-point scales (0–9) adapted from a similar questionnaire used in previous research on caffeine (e.g. Rogers et al. 2005). ‘Headache’, ‘heart pounding’, ‘jittery/ shaky’, ‘light-headed/feeling faint/dizzy’, ‘hands trembling’, ‘scared’, and ‘feeling hot/sweating (not due to heat)’ were rated on unipolar scales labelled ‘I don’t have this feeling at all’ (left-hand end=0) and ‘I have this feeling very strongly’ (right-hand end=9). The bipolar scales were relaxed (labelled ‘anxious/tense/nervous/on edge’=0 and ‘relaxed/ calm’=9), clearheaded (labelled ‘muzzy/dazed’=0 and ‘clearheaded’=9), happy (labelled ‘sad/gloomy/miserable’= 0 and ‘happy/cheerful/light-hearted’=9) and alert (labelled ‘drowsy, sluggish, tired, fatigued’=0 and ‘alert/energetic/ lively’=9). Instructions asked participants to rate ‘how you feel RIGHT NOW’. State–Trait Anxiety Inventory The State–Trait Anxiety Inventory (STAI; Spielberger Depression, Anxiety and Stress Scales The short form of the Depression, Anxiety and Stress Scales (DASS; Lovibond and Lovibond 1995) was used as a ‘trait’ measure of depression, anxiety and stress.
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Caffeine (general) Caffeine (general)
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Coffee
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Chocolate
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Energy drinks
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Gum
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Medicine/Supplement
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Soda
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Tea
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Measured Measured
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Self-report
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Children
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Adolescents
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Adults Adults
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Pregnant Women
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What was the reference, comparison, or control group(s)? (e.g. high vs low consumption, number of cups, etc.) placebo (no caffeine) vs 250 mg caffeine
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What were the listed confounders or modifying factors as stated by the authors? (e.g. multi-variable components of models.  Copy from methods) Post-treatment data for MAPS and blood pressure were analyzed using analysis of covariance with caffeine (caffeine/placebo) and theanine (theanine/placebo) and computer-task order (visual probe task first/facial expression recognition task first) as between-subjects factors and pre-treatment (baseline) data for the measure as the covariate.
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Provide a general description of results (as reported by the authors). MAPS questionnaire: Caffeine increased jitteriness (F=4.46, P=0.041) and alertness (graphical data shown in Figure 1 of the study) and had a similar, although statistically non-significant, effect on ‘heart pounding’ (data not shown). [no discussion in results section from authors on headache, scared, or State anxiety but Table 2 shows both to be F<1 for the caffeine treatment group.
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Did the authors perform a dose-response analysis (or trend/related analysis)? No
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What were the authors's observations re: trend analysis?
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What were the author's conclusions? In the present study, raised blood pressure after caffeine was accompanied by increased jitteriness, but theanine only antagonised caffeine’s effect on blood pressure. Although caffeine also increased somatic symptoms of anxiety [jitteriness and (non-significantly) heart pounding], it did not affect subjective anxiety (relaxed and scared ratings) or scores on the STAI state-anxiety subscale, which comprises predominantly subjective and cognitive descriptors. Nor was there evidence of an effect of caffeine on anxiety from responses on the visual probe task
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What were the sources of funding? The authors thank Unilever plc for donation of the theanine-containing drinks used in this study and Mars UK for permission to cite the unpublished results on effects of theanine on blood pressure from a previous study. The unpublished research on perceived effects of coffee and tea (Bristol Dietary Caffeine and Health Study) was supported by BBSRC.
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What conflicts of interest were reported? N/A
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Does the exposure (dose) need to be standardized to the SR? No
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Provide calculations/conversions for the exposure based on the decision tree in the guide (for all endpoints/exposure levels of interest).
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List all the endpoint(s) followed by the dose (mg) which will be used in comparison to Nawrot.  Characterize value as LOAEL/NOAEL, etc. if possible.  Anxiety - NOAEL = 250 mg/day Jitteriness - LOAEL = 250 mg/day Headache - NOAEL = 250 mg/day Scared - NOAEL = 250 mg/day
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Notes regarding selection/listing of endpoints and exposures/doses to be compared to Nawrot. single dose effect seen at doses lower than Nawrot, although notable inconsistency between state anxiety rating and jitteriness.
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What is the importance of the study with respect to the adverseness of the outcome? Important
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