Long-term walnut intake and brain function in abdominally obese adults

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This interventional study investigates the effects of daily walnut consumption for 24 weeks on brain vascular function and insulin sensitivity in healthy adults with abdominal obesity. The study will measure regional brain blood flow responses before and after intranasal insulin, along with cognitive performance and brain reward signals related to appetite. Participants are 45 to 75 years old, meet metabolic and anthropometric criteria, and will be monitored for safety and adherence. The trial is conducted at Maastricht University, with collaboration from the California Walnut Commission. Primary objectives focus on brain vascular function and insulin sensitivity, with secondary aims on cognitive outcomes and appetite regulation.

Why it matters

Who can join: the full rules

Inclusion Criteria:

* Men and women, aged between 45-75 years
* Women postmenopausal: two or more years after last menstruation
* Waist circumference of ≥102 cm for men and ≥88 cm for women (abdominal obesity)
* Fasting plasma glucose \< 7.0 mmol/L
* Fasting serum total cholesterol \< 8.0 mmol/L
* Fasting serum triacylglycerol \< 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:

* Allergy or intolerance to walnuts
* Left-handedness (effects on brain function differ between left- and right-handed adults)
* 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 (e.g., dietary fiber or antioxidant dietary supplements (vitamin C and E), fish or seaweed oil capsules) known to interfere with the main outcomes as judged by the principal investigators
* Use of 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)

Where it's running

• Maastricht University, Department of Nutrition and Movement Sciences
  Maastricht, Limburg, Netherlands Recruiting

Study contacts

• Study coordinator: Peter J. Joris, PhD
• Email: p.joris@maastrichtuniversity.nl
• Phone: +31883887250

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How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.