An interventional study of Avocados in Prediabetes, Brain Insulin Sensitivity and Cerebral Blood Flow, sponsored by Maastricht University Medical Center. Not yet recruiting at 1 site in Netherlands. Open to participants aged 40 Years to 75 Years. Per ClinicalTrials.gov, last updated 2026-08-27.
Sponsored by Maastricht University Medical Center · Not applicable, Interventional, and Prevention
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.
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.
Exclusion Criteria:
Both arms receive the intervention. Arm 1 is consuming 1 or no avocado a day for the first 12 weeks of the study.
Dietary Supplement: Avocados
Both arms receive the intervention but arm 2 is consuming 1 or no avocado a day for the last 12 weeks of the study.
Dietary Supplement: Avocados
Participants need to consume 1 avocado a day for 12 weeks.
Cerebral Blod Flow (CBF)
CBF will be non-invasively measured using the gold-standard methodology pseudo-continuous arterial spin labeling magnetic resonance imaging (pCASL MRI)
Time frame: CBF will be assessed at baseline, after period 1 (after 12 weeks), and at the end of the study (after 32 weeks)
Endothelial function (flow mediated dilation)
To assess endothelial function changes in diameter during Flow-Mediated Dilation (FMD) of the brachial artery will be measured using ultrasound
Time frame: Will be assessed after period 1 (12 weeks) and after period 2 (32 weeks)
Endothelial function (carotid artery reactivity)
Changes in diameter during Carotid Artery Reactivity (CAR) in response to a cold stressor will be assessed using ultrasound
Time frame: Will be assessed after period 1 (12 weeks) and after period 2 (32 weeks)
Aterial stiffness
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
Time frame: Wll be assessed after period 1 (12 weeks) and after period 2 (32 weeks)
Cerebral Blood Flow (CBF) in response to intranasal insulin delivery
CBF will be non-invasively measured using the gold-standard methodology pseudo-continuous arterial spin labeling magnetic resonance imaging (pCASL MRI)
Time frame: This will be assessed after period 1 (12 weeks) and after period 2 (32 weeks)
Cognitive Performance
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.
Time frame: Cognitive parameters will be assessed at baseline, after period 1 (after 12 weeks), and at the end of the study (after 32 weeks)
Bloodoxygen level-dependent (BOLD) functional MRI (fMRI) activity to measure appetite-related brain reward activity
BOLD fMRI activity will be measured before and while participants receive visual stimuli with food or non-food items.
Time frame: Will be assessed after period 1 (12 weeks) and after period 2 (32 weeks)
Peripheral insulin sensitivity
7-point oral glucose tolerance test (OGTT) to determine insulin sensitivity based on insulin and glucose concentrations, Matsuda index and 2h glucose tolerance (2h glucose concentrations)
Time frame: Will be assessed after period 1 (12 weeks) and after period 2 (32 weeks)
Depression
The Beck Depression Inventory (BDI) scores on a 4-point scale (0-3) with a total score between 0 and 63. A higher score suggests more as well as more severe depressive symptoms.
Time frame: Will be assessed after period 1 (12 weeks) and after period 2 (32 weeks)
Mood
Profile of Mood States (POMS) questionnaire. The POMS is a 65-item psychological inventory rated on a 5-point Likert scale (0 = Not at all to 4 = Extremely). It entails distinct mood subscales. Subscale scores are summed, and Total Mood Disturbance (TMD) is calculated by adding negative moods and subtracting vigor.
Time frame: Will be assessed after period 1 (12 weeks) and after period 2 (32 weeks)
Stress
Perceived Stress Scale (PSS) questionnaire. The PSS scores between 0 and 40 with higher scores being indicative of higher perceived stress.
Time frame: Will be assessed after period 1 (12 weeks) and after period 2 (32 weeks)
Sleep characteristics
Pittsburgh Sleep Quality Index (PSQI) questionnaire to assess sleep duration, quality, latency, and efficiency. The PSQI scores between 0 and 21 with higher scores being indicative of worse sleep disturbance and greater dysfunction. A score above 5 suggests clinically poor sleep.
Time frame: Will be assessed after period 1 (12 weeks) and after period 2 (32 weeks)
Office Blood Pressure
Office blood pressure and heart rate
Time frame: Will be assessed after period 1 (12 weeks) and after period 2 (32 weeks)
24h ambulatory blood pressure
24h ambulatory blood pressure measured every 15 min
Time frame: Will be assessed after period 1 (12 weeks) and after period 2 (32 weeks)
Lipid metabolism
Circulating triacylglycerol, High-Density Lipoprotein (HDL) cholesterol, Low-Density Lipoprotein (LDL) cholesterol, and Total Cholesterol concentrations
Time frame: Will be assessed at baseline, after period 1 (after 12 weeks), and at the end of the study (after 32 weeks)
Markers related to low-grade systemic inflammation
Interleukin (IL)-1β, IL-6, IL-8, tumor necrosis factor (TNF)a, monocyte chemo attractant protein (MCP)-1, C-reactive protein (hsCRP) and serum amyloid A (SAA)
Time frame: Will be assessed at baseline, after period 1 (after 12 weeks), and at the end of the study (after 32 weeks)
Body Composition - Fat Free Mass
BodPod will be used to measure fat free mass (weight).
Time frame: Will be assessed at baseline, after period 1 (after 12 weeks), and at the end of the study (after 32 weeks)
Body Composition - Fat Mass
BodPod will be used to measure fat mass (weight)
Time frame: Will be assessed at baseline, after period 1 (after 12 weeks), and at the end of the study (after 32 weeks)
Weight
Weight in kilograms
Time frame: Will be assessed at baseline, after period 1 (after 12 weeks), and at the end of the study (after 32 weeks)
Waist circumference
Waist circumference in centimeters
Time frame: Will be assessed at baseline, after period 1 (after 12 weeks), and at the end of the study (after 32 weeks)
Hip circumference
Hip circumference in centimeters
Time frame: Will be assessed at baseline, after period 1 (after 12 weeks), and at the end of the study (after 32 weeks)
Food intake
Food intake will be assessed using the Food Frequency Questionnaire
Time frame: Will be assessed at baseline, after period 1 (after 12 weeks), and at the end of the study (after 32 weeks)
Anxiety
The State-Trait Anxiety Inventories (STAI scores between 20 and 80. Scores between 20 and 37 are indicative of low anxiety, scores between 38 and 44 suggest moderate and scores between 45 and 80 suggest high anxiety.
Time frame: Will be assessed after period 1 (12 weeks) and after period 2 (32 weeks)
Plan to share: Undecided
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Maastricht University Medical Center