The Mechanistic Effect of Ketones on Cerebral Blood Flow and Cerebrovascular Function
Trial Snapshot
- Phase
- Not Applicable
- Status
- Completed
- Sponsor
- McMaster University
- Enrollment
- 23
- Locations
- 1
- Primary Endpoint
- Resting cerebral blood flow (CBF)
Study Overview
Brief Summary
Oral supplements containing exogenous ketones have recently become available and represent a novel tool for increasing plasma ketone bodies without the need for dietary restriction. Early evidence suggests that oral ketone supplements may enhance cerebral blood flow (CBF). However, a higher dose of a ketone monoester has been shown to slightly lower blood pH and reduce end-tidal CO2 (PetCO2) due to compensatory hyperventilation, which is accompanied by parallel reductions in CBF. Whether reductions in PetCO2 causes reductions in CBF is currently unknown.
The purpose of this study is to investigate the effect of manipulating PetCO2 at normocapnia (PetCO2 maintained at baseline) or poikilocapnia (no PetCO2 targeting; breathing room air), following the ingestion of a dose of a ketone monoester on CBF and cerebrovascular reactivity to CO2 in young adults.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Basic Science
- Masking
- Double (Participant, Outcomes Assessor)
Eligibility Criteria
- Ages
- 18 Years to 35 Years (Adult)
- Sex
- All
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •Having a normal blood pressure (≤125/≤85 mmHg)
- •Between the ages of 18 and 35
Exclusion Criteria
- •Individuals who are obese (body mass index > 30 kg/m^2)
- •Individuals who smoke
- •Individuals with respiratory illnesses
- •A history of type 2 diabetes, hypoglycemia, or cardiovascular diseases (i.e. heart attack, stroke)
- •Individuals currently following a ketogenic diet or taking ketone supplements
- •Individuals with a history of concussion(s) with persistent symptoms
- •Individuals participating in elite-level physical training (i.e. varsity athletics)
Arms & Interventions
Poikilocapnia
Room air-breathing
Intervention: Poikilocapnia (Dietary Supplement)
Normocapnia
Breathing air mixture with slightly elevated CO2 to maintain PetCO2 to resting baseline levels
Intervention: Normocapnia (Dietary Supplement)
Outcomes
Primary Outcomes
Resting cerebral blood flow (CBF)
Time Frame: 90-minutes
Measured via duplex ultrasound of the internal carotid artery and vertebral artery
Secondary Outcomes
- Plasma beta-hydroxybutyrate area under the curve(90-minutes)
- Middle Cerebral Artery Blood Velocity(90-minutes)
- Cerebrovascular Reactivity of the Internal Carotid and Middle Cerebral Artery as assessed by Duplex Ultrasound and Transcranial Doppler Ultrasound, respectively.(90-minutes)
- Blood pH(90-minutes)
- End-tidal CO2(90-minutes)
- Mean arterial pressure (MAP)(90-minutes)
Investigators
Jeremy Walsh
Assistant Professor
McMaster University