Impaired brain vascular function precedes the development of reduced cognitive performance, while brain insulin-resistance is also associated with cognitive decline. The Mediterranean diet, which is rich in nuts, may protect against the development of impaired cognitive performance. The hypothesis is that long-term mixed nut consumption increases brain insulin-sensitivity thereby improving brain vascular function and cognitive performance. The primary objective is to evaluate in elderly men and women the effect of 16-week mixed nut consumption on cerebral blood flow, as quantified by the non-invasive gold standard magnetic resonance imaging (MRI)-perfusion method Arterial Spin Labelling (ASL). Cerebral blood flow is a robust and sensitive physiological marker of brain vascular function. Secondary objectives are to investigate effects on the cerebral blood flow response to intranasal insulin delivery - a marker of insulin-sensitivity in the human brain - as quantified by ASL, and cognitive functioning as assessed with a neuropsychological test battery.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
DOUBLE
Enrollment
28
Study volunteers will receive daily 60 g of mixed nuts (15 g walnut, 15 g cashew, 15 g hazelnut, 15 g pistachio) for 16 weeks.
Maastricht University Medical Center
Maastricht, Limburg, Netherlands
Brain Vascular Function
Cerebral blood flow as quantified non-invasively by the MRI perfusion method Arterial Spin Labeling (ASL)
Time frame: Change in outcomes at the end of a 16-week mixed nuts intervention and 16-week control period.
Brain Insulin Sensitivity
Change in cerebral blood flow, as quantified non-invasively by the MRI perfusion method Arterial Spin Labeling (ASL), before and after application of intranasal insulin (160 IU)
Time frame: Change in outcomes at the end of a 16-week mixed nuts intervention and 16-week control period.
Cognitive performance
Cambridge Neuropsychological Test Automated Battery (CANTAB)
Time frame: Change in outcomes at the end of a 16-week mixed nuts intervention and 16-week control period.
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