Brain Health, Brain Insulin Sensitivity, Cerebral Blood Flow, Food Reward, Obesity & Overweight, Prediabetes, Satiety and Food Intake, Vascular Function
Conditions
Keywords
Avocados, Brain insulin sensitivity, Brain vascular function, Cerebral Blood Flow, CBF, pCASL MRI, CANTAB, Overweight, Obesity, cognitive performance, brain health
Brief summary
Primary aim of the study is to assess the effect of 12-week daily avocado consumption on cerebral blood flow and markers of cardio- and vascular health in both, the periphery and the brain, in pre-diabetic individuals with overweight or obesity. Secondary objective is to assess the effects of 12-week daily avocado consumption on brain insulin sensitivity after intranasal insulin delivery, vascular function, markers of metabolic health, cognition, and psychological well-being. For that purpose a total of 34 men and women between the ages of 40-75 years old, will participate in a randomised crossover intervention study.
Detailed description
Daily intake of avocado, a food rich in MUFA, PUFA and other essential nutrients such as folate and potassium, has previously been shown to lower systemic markers of cardiovascular risk as well as inflammation in overweight/obese individuals. Especially individuals with cardiovascular disease, or those at an increased risk for cardiovascular disease appear to benefit from regular avocado consumption. In addition to improvements in cardiovascular disease, large cross-sectional studies have linked avocado consumption to a lower risk for metabolic disease, including type 2 diabetes. Despite the beneficial systemic effects observed, the interaction of peripheral cardiovascular risk- and vascular function markers with brain vascular health remains unclear. Furthermore, the clinical implications of this interaction, especially in a population at risk, are unknown. A total of 34 men and women between the ages of 40-75 years old, with overweight/obesity (BMI: 26-40 kg/m2) will consume a daily avocado (intervention) or no avocado for 12 week in a crossover design. The primary outcome parameter of the intervention will be cerebral blood flow (CBF). Secondary outcomes include measures for endothelial function (brachial artery flow mediated vasodilation (FMD), carotid artery reactivity (CAR)) and arterial stiffness (pulse wave velocity (PWV), carotid artery distensibility). More cardiometabolic risk markers measured will include office blood pressure, serum lipids, lipoprotein and metabolite profiling, hemostatic factors and plasma biomarkers for low-grade systemic inflammation including IL-6, IL-8, TNF-α, CRP and SAA). Cognitive performance will be assessed in the domains of executive function, memory, psychomotor speed and attention with the Cambridge Neuropsychological Test Automated Battery (CANTAB) as well as the Erikson Flanker test.
Interventions
DIETARY_SUPPLEMENTAvocados
Participants need to consume 1 avocado a day for 12 weeks.
Sponsors
Maastricht University Medical Center
Avocado Nutrition Center
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
PREVENTION
Masking
TRIPLE (Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
40 Years to 75 Years
Healthy volunteers
No
Inclusion criteria
* Men and women, aged between 40-75 years * Pre-diabetes: (A1C of 5.7%-6.4%, a fasting plasma glucose (FPG) of 100-125 mg/dL, or a 2-hour oral glucose tolerance test (OGTT) result of 140-199 mg/dL) * BMI ³ 25 kg/m2 * Fasting serum total cholesterol \< 8.0 mmol/L * Systolic blood pressure \< 160 mmHg and diastolic blood pressure \< 100 mmHg * 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
Exclusion criteria
* Age less than 40 years old or older than 75 years * BMI \< 25 kg/m2 * Type 1 or type 2 diabetes * habitual consumption of more than 1 avocado/ week * Left-handedness * Fasting serum total cholesterol \> 8.0 mmol/L * Current smoker, or smoking cessation \< 12 months * Abuse of drugs * More than 3 alcoholic consumptions per day * Use medication to treat blood pressure, lipid or glucose metabolism * 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) * Blood donation in the 8 weeks before the start of the study * Difficulties to draw blood
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Cerebral Blod Flow (CBF) | CBF will be assessed at baseline, after period 1 (after 12 weeks), and at the end of the study (after 32 weeks) | CBF will be non-invasively measured using the gold-standard methodology pseudo-continuous arterial spin labeling magnetic resonance imaging (pCASL MRI) |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Endothelial function (flow mediated dilation) | Will be assessed after period 1 (12 weeks) and after period 2 (32 weeks) | To assess endothelial function changes in diameter during Flow-Mediated Dilation (FMD) of the brachial artery will be measured using ultrasound |
| Endothelial function (carotid artery reactivity) | Will be assessed after period 1 (12 weeks) and after period 2 (32 weeks) | Changes in diameter during Carotid Artery Reactivity (CAR) in response to a cold stressor will be assessed using ultrasound |
| Aterial stiffness | Wll be assessed after period 1 (12 weeks) and after period 2 (32 weeks) | Pulse Wave Analysis (PWA) of the radial artery and Femoral-to-carotid Pulse Wave Velocity (PWV) in m/s will be measured with a tonometer using Sphygomocor |
| Cerebral Blood Flow (CBF) in response to intranasal insulin delivery | This will be assessed after period 1 (12 weeks) and after period 2 (32 weeks) | CBF will be non-invasively measured using the gold-standard methodology pseudo-continuous arterial spin labeling magnetic resonance imaging (pCASL MRI) |
| Cognitive Performance | Cognitive parameters will be assessed at baseline, after period 1 (after 12 weeks), and at the end of the study (after 32 weeks) | Cognitive performance measurement of the following cognitive domains: memory, executive function and psychomotor speed. Measurements will be performed using the Cambridge Neuropsychological Test Automated Battery (CANTAB) and the Flanker test. |
Countries
Netherlands
Contacts
CONTACTTanja Adam, PhD
CONTACTTiago Wiesner, MSc
Outcome results
None listed