Brain Insulin Sensitivity, Brain Vascular Function, Cerebral Blood Flow, Cognitive Performance, Appetite Control
Conditions
Brief summary
Disturbances in brain insulin-sensitivity are not only observed in obesity and type 2 diabetes (T2D), but also during brain aging and in dementia. Ketone monoester supplements may improve brain insulin-sensitivity, which can be quantified by measuring the gray-matter cerebral blood flow (CBF) response to intranasally administered insulin. We hypothesize that acute ketone monoester supplementation increases (regional) brain vascular function and insulin-sensitivity thereby improving cognitive performance and appetite control. The primary objective is to evaluate in older men the acute effect of ketone monoester supplementation on (regional) brain vascular function and insulin-sensitivity, as quantified by the non-invasive gold standard magnetic resonance imaging (MRI)-perfusion method Arterial Spin Labelling (ASL). The CBF response to intranasal insulin is a robust and sensitive physiological marker of brain insulin-sensitivity. Secondary objectives are to investigate effects on cognitive performance as assessed with a neuropsychological test battery, and appetite control as quantified by functional MRI (fMRI) with visual food cues.
Interventions
DIETARY_SUPPLEMENTKetone Monoester
Ketone monoester supplement (395 mg/kg body mass)
DIETARY_SUPPLEMENTPlacebo
The placebo will be taste-matched to the active supplement for bitterness using denatonium benzoate and volume-matched with water
Sponsors
Maastricht University Medical Center
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Intervention model description
Study participants will receive in random order acutely 395 mg/kg body weight ketone monoesters or placebo, seperated by a wash-out period of at least 1 week.
Eligibility
Sex/Gender
MALE
Age
60 Years to 75 Years
Healthy volunteers
Yes
Inclusion criteria
* Men, aged between 60-75 years * BMI between 25-30 kg/m2 * Fasting plasma glucose \< 7.0 mmol/L * Fasting serum TC \< 8.0 mmol/L * Fasting serum TAG \< 4.5 mmol/L * Systolic blood pressure \< 160 mmHg and diastolic blood pressure \< 100 mmHg * Stable body weight (weight gain or loss \< 3 kg in the past three months) * Willingness to give up being a blood donor from 8 weeks before the start of the study, during the study and for 4 weeks after completion of the study * No difficult venipuncture as evidenced during the screening visit
Exclusion criteria
* Women * Left-handedness * Following a low-carbohydrate diet or consuming nutritional ketone supplements * Current smoker, or smoking cessation \< 12 months * Diabetic patients * Familial hypercholesterolemia * Abuse of drugs * More than 3 alcoholic consumptions per day * Use of products or dietary supplements known to interfere with the main outcomes as judged by the principal investigators * Use medication to treat blood pressure, lipid or glucose metabolism, or neurological or mental disorders. * Use of an investigational product within another biomedical intervention trial within the previous 1-month * Severe medical conditions that might interfere with the study, such as epilepsy, asthma, kidney failure or renal insufficiency, chronic obstructive pulmonary disease, inflammatory bowel diseases, auto inflammatory diseases and rheumatoid arthritis * Active cardiovascular disease like congestive heart failure or cardiovascular event, such as an acute myocardial infarction or cerebrovascular accident * Contra-indications for MRI imaging (e.g. pacemaker, surgical clips/material in body, metal splinter in eye, claustrophobia).
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Brain Vascular Function | Change from placebo intervention at 30 minutes after supplement intake | Cerebral blood flow as quantified non-invasively by the MRI perfusion method Arterial Spin Labeling (ASL) |
| Brain Insulin Sensitivity | Change from placebo intervention at 60 minutes after supplement intake | Cerebral blood flow measurements before and after a nasal insulin spray as quantified non-invasively by the MRI perfusion method Arterial Spin Labeling (ASL) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Brain Perfusion | Change from placebo intervention at 120 minutes after supplement intake | Transcranial Doppler (TCD) ultrasound will be used to assess the velocity of blood flow through the middle cerebral artery (MCA) |
| Blood pressure | Change from placebo intervention at 90 minutes after supplement intake | Office blood pressure and heart rate |
| Ketone metabolism | During 120 minutes following supplement intake | Circulating beta-hydroxybutyrate concentrations |
| Glucose metabolism | During 120 minutes following supplement intake | Circulating glucose and insulin concentrations |
| Appetite-related brain reward activity | Change from placebo intervention at 40 minutes after supplement intake | Blood oxygenation level-dependent (BOLD)-functional MRI (fMRI) response to food cues |
| Appetite hormones | During 120 minutes following supplement intake | Circulating ghrelin concentrations |
| Perceived hunger and satiety | During 120 minutes following supplement intake | Visual analogue scale (VAS) questionnaires |
| Anthropometric measurements | Before supplement intake | Weight, length, waist and hip circumference |
| Food intake | Once 120 minutes following supplement intake | Food Frequency Questionnaire to assess food intake over the past month |
| Markers related to low-grade systemic inflammation | During 120 minutes following supplement intake | Circulating high-sensitive C-reactive protein concentrations |
| Cognitive Performance | Change from placebo intervention at 120 minutes after supplement intake | Cambridge Neuropsychological Test Automated Battery (CANTAB) |
Countries
Netherlands
Outcome results
None listed