Healthy
Conditions
Brief summary
Assess the effects of adding theanine to a caffeinated beverage on changes in blood pressure during acute mental stress.
Detailed description
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.
Interventions
OTHERCombination of caffeine and theanine
Beverage containing caffeine and theanine
OTHERCaffeine
Beverage containing caffeine
Sponsors
University College, London
Unilever R&D
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 45 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Systolic blood pressure during stress | Between 30-45 minutes after test product intake | Systolic blood pressure during acute mental stress |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Diastolic blood pressure during stress | Between 30-45 minutes after test product intake | Diastolic blood pressure during acute mental stress |
| Systolic blood pressure after stress | Between 45-60 minutes after test product intake | Systolic blood pressure immediately after acute mental stress |
| Diastolic blood pressure after stress | Between 45-60 minutes after test product intake | Diastolic blood pressure immediately after acute mental stress |
| STAI before and immediately after stress | -15 and 45 relative to test product intake | Self-reported mental state: State-Trait Anxiety Inventory |
| UWIST before and immediately after stress | -10, 45 minutes relative to test product intake | Self-reported mental state: University Of Wales Institute of Science and Technology mood adjective questionnaire |
Other
| Measure | Time frame | Description |
|---|---|---|
| Performance mirror tracing | Between 30-45 minutes after test product intake | Task performance on mirror tracing task |
| Systolic blood pressure, free living phase | Between 80-270 minutes after test product intake | Ambulatory systolic blood pressure during free living phase |
| Diastolic blood pressure, free living phase | Between 80-270 minutes after test product intake | Ambulatory diastolic blood pressure during free living phase |
| Cortisol, free living phase | 140, 200 and 260 minutes after test product intake | Concentration of cortisol in saliva during free living phase |
| STAI, free living phase | 140, 200 and 260 minutes after test product intake | Self-reported mental state: State-Trait Anxiety Inventory during free living phase |
| UWIST, free living phase | 140, 200 and 260 minutes after test product intake | Self-reported mental state: University Of Wales Institute of Science and Technology) mood adjective questionnaire during free living phase |
| Pulse pressure during stress | Between 30-45 minutes after test product intake | Mean pulse pressure during mental stress |
| Cortisol in saliva before and immediately after stress | -5, 45 min relative to test product intake | Concentration of cortisol in saliva |
| Mental wellbeing | 7 consecutive days prior to the lab sessions | Mental well being as assessed by on line survey an each evening during the 7 day period the accelerometer is worn. |
| Physical activity | 7 consecutive days prior to the lab sessions | Habitual patterns in physical activity as measured by accelerometer |
| STAI screening | Screening | State-Trait Anxiety Inventory (STAI) - Trait version, covariate |
| CES-D | Screening | Center for Epidemiologic Studies Depression scale, covariate |
| CISS | Screening | CISS coping scale, covariate |
| loneliness | Screening | UCLA loneliness scale, covariate |
| Perceived stress | Screening | Perceived Stress Scale, covariate |
| Pulse pressure after stress | Between 45-60 minutes after test product intake | Mean pulse pressure after acute mental stress |
| Heart rate during stress | Between 30-45 minutes after test product intake | Heart rate during acute mental stress |
| Heart rate after stress | Between 45-60 minutes after test product intake | Heart rate immediately after acute mental stress |
| Heart rate variability during stress | Between 30-45 minutes after test product intake | Heart rate variability during acute mental stress |
| Heart rate variability after stress | Between 45-60 minutes after test product intake | Heart rate variability immediately after acute mental stress |
| Performance STROOP | Between 30-45 minutes after test product intake | Task performance on STROOP task |
Countries
United Kingdom
Outcome results
None listed