Long-Term Effects of Walnut Consumption on Brain Function

Sponsor
Maastricht University Medical Center
Study ID
NCT07422220
Status
Not Yet Recruiting

Notify me when recruiting opens

Save your spot on the interest list for this study. We'll keep your details with this study so our team can follow up when recruiting opens.

Not yet recruiting

Add your contact details and location so we can keep your interest tied to this study.

Conditions

  • Abdominal Obesity
  • Brain Insulin Sensitivity
  • Brain Vascular Function
  • Cerebral Blood Flow
  • Cognitive Decline
  • Cognitive Performance
  • Food Reward
  • Healthy
  • Satiety and Food Intake

Eligibility Criteria

Sex
ALL
Age
45 Years - 75 Years
Healthy Volunteers
Accepted

Interventions

  • Walnuts — DIETARY_SUPPLEMENT
    24-week consumption of 50 g/day of walnuts as part of a healthy diet according to the Dutch dietary guidelines

Study Details

Rationale: Healthy foods, including mixed nuts, may improve brain function, which is essential for cognitive and metabolic health, and may contribute to improved food intake regulation. It is therefore important to investigate the specific effects of walnuts on cerebral blood flow responses before and after intranasal insulin administration, as well as their associated functional benefits. The investigators hypothesize that long-term walnut consumption improves vascular function and insulin-sensitivity in the brain, thereby enhancing cognitive performance and appetite control in abdominally obese men and women. Objective: The primary objectives are to investigate in abdominally obese adults the effects of 24-week walnut consumption on (regional) vascular function and insulin-sensitivity in the brain, while the investigators will also assess changes in cognitive performance and appetite-related brain reward activity (secondary objectives). Cerebral blood flow responses before (brain vascular function) and after the administration of intranasal insulin spray (brain insulin-sensitivity) will be quantified by the non-invasive gold standard magnetic resonance imaging (MRI)-perfusion method Arterial Spin Labeling (ASL). Study design: This intervention study will have a randomized, controlled parallel design. The total study duration will be 24 weeks. Study population: Fifty-five abdominally obese men and (postmenopausal) women (aged 45-75 years) without a history of cardiovascular diseases or complaints will participate. This study population is expected to have a decreased cerebral blood flow at baseline and are also at increased risk of cognitive impairment, allowing for improvement by the intervention. Intervention: Study participants will receive daily 50 g (about 15% of energy) of raw walnuts (walnut intervention) or no walnuts (control intervention) for 24 weeks. Main study parameters/endpoints: At baseline and after 24 weeks (follow-up), participants will visit the research facilities for assessments. The primary endpoint is the difference in the cerebral blood flow response before and after intranasal insulin administration between the walnut and control intervention. Cognitive performance will be assessed, while the investigators will also focus on appetite-related brain reward activity (secondary outcomes).

Key Dates

First listed
Feb 19, 2026
Start date
Feb 28, 2026
Status verified
Feb 2026
Primary completion
Aug 31, 2027
Completion
Aug 31, 2027

Study Design

Enrollment
55 participants (estimated)
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION

Arms

  • Experimental: Walnut
    Receive 50g walnuts per day
  • No Intervention: Control
    Does not receive walnuts and is supposed to refrain from nut consumption

Primary Outcome Measure

Cerebral blood flow (CBF) prior to and after application of intranasal insulin [ Time Frame: From enrollment to the end of treatment at 24 weeks ]

Central Contacts

Related Studies