Acute Effects of Organic Guayusa Extract

Acute, Dose-Response Effects of Organic Guayusa Extract on Cognitive Performance, Mood, Resting Metabolism, and Blood Pressure, Heart Rate, and Heart Electrical Activity

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.

Study Overview

• Status: Completed
• Conditions: Acute Physiological Effects of Organic Guayusa Extract
• Intervention / Treatment: Dietary supplement: Acute Moderate-Dose Guayusa Extract Supplementation; Dietary supplement: Acute High-Dose Guayusa Extract Supplementation; Dietary supplement: Placebo

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.

• Study Type: Interventional
• Enrollment (Actual): 32
• Phase: Not Applicable

Contacts and Locations

Study Locations

• United States
  • Iowa
    • Iowa City, Iowa, United States, 52242
      • Integrative Laboratory of Applied Physiology and Lifestyle Medicine

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

• 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

Exclusion Criteria:

• 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 Plan

How is the study designed?

Design Details

• Primary Purpose: Other
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Quadruple

Number of Arms

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Moderate-Dose Guayusa Extract; Acute, single dose of 600 mg Organic Guayusa Extract	Dietary supplement: Acute Moderate-Dose Guayusa Extract Supplementation; Participants will consume two vegan capsules with one capsule containing 600 mg AmaTea® and 1 containing 600 mg dextrose.
Experimental: High-Dose Guayusa Extract; Acute, single dose of 1200 mg Organic Guayusa Extract	Dietary supplement: Acute High-Dose Guayusa Extract Supplementation; Participants will consume two vegan capsules with each capsule containing 600 mg AmaTea® (1200 mg total).
Placebo Comparator: Placebo; Acute, single dose of Placebo (dextrose)	Dietary supplement: Placebo; Participants will consume two vegan capsules with each capsule containing 600 mg dextrose (1200 mg total).

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Mood	Calculated as Total Mood Disturbance (arbitrary units) using the Profile of Mood States Short Form Questionnaire.	90-minutes Post-supplementation
Psychomotor Speed	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.	60-minutes Post-supplementation
Executive Function	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.	60-minutes Post-supplementation

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Jitteriness	Participants will describe how jittery they feel after supplemention using a 0-100 mm visual analog scale.	90-minutes Post-supplementation
Focus	Participants will describe how focused they feel after supplemention using a 0-100 mm visual analog scale.	90-minutes Post-supplementation
Energy	Participants will describe how energetic they feel after supplemention using a 0-100 mm visual analog scale.	90-minutes Post-supplementation
Resting Metabolic Rate	Resting metabolic rate (kcal/min) will be quantified from resting, fasted analyses of pulmonary gas exchange.	50 minutes post-supplementation
Resting Fat Oxidation	Resting fat oxidation (g/min) will be quantified from resting, fasted analyses of pulmonary gas exchange.	50 minutes post-supplementation
Resting Heart Rate	Heart rate (bpm) will be quantified from a standard 12-lead ECG	-10 minutes before supplementation, 40 minutes post-supplementation
Resting Blood Pressure	Systolic, diastolic, and pulse pressures (mmHg) will be quantified from brachial artery via automated sphygmomanometer.	-10 minutes before supplementation, 40 minutes post-supplementation
QTc Interval	QTc Interval (ms) will be quantified from a standard 12-lead ECG	-10 minutes before supplementation, 40 minutes post-supplementation
Sustained Attention	How well a subject can direct and focus cognitive activity on specific stimuli. Derived from performance on the 4-part continuous performance task test.	60-minutes Post-supplementation
Working Memory	How well a subject can perceive and attend to symbols using short-term memory processes.	60-minutes Post-supplementation
Cognitive Flexibility	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.	60-minutes Post-supplementation
Motor-Cognitive Reaction Time	Motor-cognitive reaction times (ms) will be quantified from motor cognitive (reactionary hop) tests	100-minutes Post-supplementation

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Vigor	Vigor will be quantified using the Profile of Mood State Short Form Questionnaire.	90-minutes Post-supplementation
Tension	Tension will be quantified using the Profile of Mood State Short Form Questionnaire.	90-minutes Post-supplementation
Fatigue	Fatigue will be quantified using the Profile of Mood State Short Form Questionnaire.	90-minutes Post-supplementation
Anger	Anger will be quantified using the Profile of Mood State Short Form Questionnaire.	90-minutes Post-supplementation
Confusion	Confusion will be quantified using the Profile of Mood State Short Form Questionnaire.	90-minutes Post-supplementation
Stress	Stress will be quantified using the Profile of Mood State Short Form Questionnaire.	90-minutes Post-supplementation
Composite Memory	How well subject can recognize, remember, and retrieve words and geometric figures. Assessed as a composite performance indicator during the Verbal Memory and Visual Memory Tests.	60-minutes Post-supplementation
Reaction Time	How quickly the subject can react, in milliseconds, to a simple and increasingly complex direction set.	60-minutes Post-supplementation
Complex Attention	Ability to track and respond to a variety of stimuli over lengthy periods of time and/or perform mental tasks requiring vigilance quickly and accurately.	60-minutes Post-supplementation
Reasoning	How well is subject able to recognize, reason and respond to non-verbal visual-abstract stimuli. Assessed from the non-verbal reasoning test as the difference between the number of correct responses and commission errors.	60-minutes Post-supplementation

Collaborators and Investigators

• Sponsor: Nathaniel Jenkins

Study record dates

Study Major Dates

• Study Start (Actual): May 16, 2022
• Primary Completion (Actual): July 13, 2022
• Study Completion (Actual): April 12, 2023

Study Registration Dates

• First Submitted: June 12, 2023
• First Submitted That Met QC Criteria: June 22, 2023
• First Posted (Actual): July 3, 2023

Study Record Updates

• Last Update Posted (Actual): July 5, 2023
• Last Update Submitted That Met QC Criteria: June 30, 2023
• Last Verified: June 1, 2023

More Information

Terms related to this study

• Keywords: dietary supplementation; blood pressure; metabolism; cognitive performance; heart rate; mood; electrocardiogram
• Other Study ID Numbers: 202202283

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No