Acute Effects of Organic Guayusa Extract
- Conditions
- Acute Physiological Effects of Organic Guayusa Extract
- Interventions
- Dietary Supplement: Acute High-Dose Guayusa Extract SupplementationDietary Supplement: Acute Moderate-Dose Guayusa Extract SupplementationDietary Supplement: Placebo
- Registration Number
- NCT05928195
- Lead Sponsor
- Nathaniel Jenkins
- Brief Summary
Guayusa extract is a caffeinated tea leaf unique blend of antioxidants and caffeine. It is marketed as an ingredient that can help support energy and performance with potential health-related benefits. It has also been indicated as being as safe as any other existing teas (i.e., green tea). However, no studies have previous studied the dose-response effects of guayusa extract for supporting cognitive function, mood, metabolism, nor its effects on resting heart rate, blood pressure, and electrocardiogram characteristics.
- Detailed Description
Guayusa extract is a caffeinated Amazonian 'super-leaf' belonging to the holly species that contains a unique blend of polyphenol antioxidants and caffeine (\~20% caffeine, 30% chlorogenic acids, 5% catechins). It is also remarkably low in tannins which are responsible for the bitter taste found in most teas - giving it a sweet flavor profile. As such, it is marketed as an ingredient that can help support energy and performance (e.g., via caffeine content) with potential health-related benefits due to its antioxidant properties. Indeed, ingredients such as these are often consumed by individuals prior to exercise in order to help improve neurocognitive performance, mood, or otherwise to support health-related goals such as metabolism. Whereas several studies have suggested that caffeine and chlorogenic acid consumption may improve performance, mood, and concentration, and some evidence in animals have linked catechin consumption to improved health outcomes, no studies have previous studied whether guayusa extract supplementation helps to support these, nor has the dose-effectiveness been tested, in humans.
In this study, the effects of acute dietary supplementation with two different doses of botanical organic guayusa extract on neurocognitive/motor-cognitive performance, mood, focus, and jitteriness, resting metabolism, and resting heart rate, blood pressure, and electrocardiogram characteristics will be examined.
Recruitment & Eligibility
- Status
- COMPLETED
- Sex
- All
- Target Recruitment
- 32
- 18-45 years, inclusive
- Physically active (>=150 min/wk or >=75 min/wk Moderate or Vigorous PA) for >=3 months
- BMI <= 30 kg/m2
- Otherwise healthy
- Habitual caffeine consumption >=200 mg/day OR 1-week washout of current caffeine usage prior to participation
- Current injury or illness that precludes exercise participation
- Current nicotine or cannabis use
- Use of prescription ADD/ADHD, anti-depressant, or other central acting medication, or previously diagnosed ADD/ADHD, clinically depressed, or generalized anxiety disorder
- Current taking prescription stimulants (i.e., Adderall, Ritalin, Vyvanse, etc.)
- Participants with a history of metabolic, hepatorenal, musculoskeletal, autoimmune, or neurologic disease; or currently taking thyroid, hormonal, hyperlipidemic, hypoglycemic, anti-hypertensive, anti-inflammatory, or anti-coagulant medications.
- Treated for Metabolic Syndrome or having been clinically diagnosed with, or taking medication for a cardiometabolic-disorder (e.g., Pre-diabetes, Type II diabetes, high blood pressure, obesity, hypercholesterolemia, etc.)
- Currently pregnant or lactating
- Diagnosed allergy to any ingredient present within the study treatments
- Current competitive NCAA athlete
- Inability or unwillingness to comply with the controls and conditions of the study
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Arm && Interventions
Group Intervention Description High-Dose Guayusa Extract Acute High-Dose Guayusa Extract Supplementation Acute, single dose of 1200 mg Organic Guayusa Extract Moderate-Dose Guayusa Extract Acute Moderate-Dose Guayusa Extract Supplementation Acute, single dose of 600 mg Organic Guayusa Extract Placebo Placebo Acute, single dose of Placebo (dextrose)
- Primary Outcome Measures
Name Time Method Mood 90-minutes Post-supplementation Calculated as Total Mood Disturbance (arbitrary units) using the Profile of Mood States Short Form Questionnaire.
Executive Function 60-minutes Post-supplementation How well participant recognized rules, categories, and manages or navigates rapid decisions making. Calculated as the differences between Shifting Attention Test Correct Responses and Errors.
Psychomotor Speed 60-minutes Post-supplementation How well participant perceived, attends, responds to visual-perceptive information, and performs motor speed and fine motor coordination. Calculated as the sum of finger taps in finger tapping test and correct responses in the symbol digit coding test.
- Secondary Outcome Measures
Name Time Method Resting Blood Pressure -10 minutes before supplementation, 40 minutes post-supplementation Systolic, diastolic, and pulse pressures (mmHg) will be quantified from brachial artery via automated sphygmomanometer.
Motor-Cognitive Reaction Time 100-minutes Post-supplementation Motor-cognitive reaction times (ms) will be quantified from motor cognitive (reactionary hop) tests
Sustained Attention 60-minutes Post-supplementation How well a subject can direct and focus cognitive activity on specific stimuli. Derived from performance on the 4-part continuous performance task test.
Jitteriness 90-minutes Post-supplementation Participants will describe how jittery they feel after supplemention using a 0-100 mm visual analog scale.
Cognitive Flexibility 60-minutes Post-supplementation How well subject is able to adapt to rapidly changing and increasingly complex set of directions and/or to manipulate the information. Assessed from the Shifting Attention Task and Stoop Test as the Shifting Attention Task Correct Responses - Shifting Attention Task Incorrect Responses and Stroop Commission Errors.
Focus 90-minutes Post-supplementation Participants will describe how focused they feel after supplemention using a 0-100 mm visual analog scale.
Resting Metabolic Rate 50 minutes post-supplementation Resting metabolic rate (kcal/min) will be quantified from resting, fasted analyses of pulmonary gas exchange.
Energy 90-minutes Post-supplementation Participants will describe how energetic they feel after supplemention using a 0-100 mm visual analog scale.
Resting Fat Oxidation 50 minutes post-supplementation Resting fat oxidation (g/min) will be quantified from resting, fasted analyses of pulmonary gas exchange.
Resting Heart Rate -10 minutes before supplementation, 40 minutes post-supplementation Heart rate (bpm) will be quantified from a standard 12-lead ECG
QTc Interval -10 minutes before supplementation, 40 minutes post-supplementation QTc Interval (ms) will be quantified from a standard 12-lead ECG
Working Memory 60-minutes Post-supplementation How well a subject can perceive and attend to symbols using short-term memory processes.
Trial Locations
- Locations (1)
Integrative Laboratory of Applied Physiology and Lifestyle Medicine
🇺🇸Iowa City, Iowa, United States