Tea Components, Mental Stress and Blood Pressure

Study Overview
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Brief Summary
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Assess the effects of adding theanine to a caffeinated beverage on changes in blood pressure during acute mental stress.

Detailed Description
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Caffeine and (mental) stress can increase blood pressure. In a typical everyday and/or work environment they commonly coincide. Tea has the reputation of being a relaxing drink. L-theanine is an amino acid found almost exclusively in tea. In a previous study it was shown that caffeine increased blood pressure, while theanine antagonised these effects. In the current study the effect of theanine to a placebo on blood pressure are directly compared.

Official Title
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A Study to Determine the Acute Effects of a Tea Component on Blood Pressure and Mental Stress Challenge

Conditions
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Healthy

Intervention / Treatment
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* Other: Combination of caffeine and theanine
* Other: Caffeine


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Apparently healthy males and females Women taking the contraceptive pill 18-45 years of age BMI 20-30 kg/m2 Normal or corrected vision Low caffeine consumers (<100mg/day) Non smokers and having been a non-smoker for > 6 months Fluent English Normotensive (>90/60 <140/90 mmHg) Exclusion Criteria: Significant current or medical history of cardiovascular disease Low or high STAI trait score in the opinion of the PI Known sensitivity to caffeine or theanine Colour blindness Alcohol consumption above 14/21 units female/male resp. per week Weight loss diet > 10% of bodyweight in the previous year Anyone with a dependency on PI or staff of Department of Epidemiology and Public Health or being an employee of Unilever Reported participation in another biomedical study < 3 months before screening

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Combination of caffeine and theanine<br>250 mg caffeine + 200 mg theanine | Other: Combination of caffeine and theanine<br>* Beverage containing caffeine and theanine<br>|
| Placebo Comparator: Caffeine<br>250 mg caffeine | Other: Caffeine<br>* Beverage containing caffeine<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Systolic blood pressure during stress | Systolic blood pressure during acute mental stress | Between 30-45 minutes after test product intake | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Diastolic blood pressure during stress | Diastolic blood pressure during acute mental stress | Between 30-45 minutes after test product intake | 
| Systolic blood pressure after stress | Systolic blood pressure immediately after acute mental stress | Between 45-60 minutes after test product intake | 
| Diastolic blood pressure after stress | Diastolic blood pressure immediately after acute mental stress | Between 45-60 minutes after test product intake | 
| STAI before and immediately after stress | Self-reported mental state: State-Trait Anxiety Inventory | -15 and 45 relative to test product intake | 
| UWIST before and immediately after stress | Self-reported mental state: University Of Wales Institute of Science and Technology mood adjective questionnaire | -10, 45 minutes relative to test product intake |