Impaired brain vascular function precedes the development of reduced cognitive performance, while brain insulin-resistance is associated with cognitive decline. Evidence from epidemiological studies has already suggested beneficial effects of wild blueberry consumption on cognitive performance. However, underlying mechanisms have not yet been established, while well-controlled trials on longer-term effects of wild blueberries on cognitive performance are highly needed. This study hypothesizes that longer-term wild blueberry intake improves (regional) brain vascular function and insulin-sensitivity, thereby improving cognitive performance in older men and women. The primary objectives are to investigate in older adults the effect wild blueberry consumption on (regional) vascular function and insulin-sensitivity in the brain, and to focus on changes in cognitive performance as assessed with the CANTAB neuropsychological test battery (i.e., secondary objective). Cerebral blood flow responses before (brain vascular function) and after the administration of intranasal insulin spray (brain insulin-sensitivity) will be non-invasively quantified by the non-invasive gold standard magnetic resonance imaging (MRI)- perfusion method Arterial Spin Labeling (ASL).
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
TRIPLE
Enrollment
36
Study volunteers will consume daily 26 grams of wild blueberry powder for 16 weeks, which has to be dissolved in a glass of water.
Maastricht University, Departement of Nutrition and Movement Sciences
Maastricht, Limburg, Netherlands
RECRUITINGMRI-brain perfusion measurement Arterial Spin Labeling
Cerebral blood flow responses before (brain vascular function) and after the administration of intranasal insulin (brain insulin-sensitivity) will be non-invasively quantified by MRI-perfusion method Arterial Spin Labeling (ASL).
Time frame: Change in brain perfusion at the end of a 16-week wild blueberry intervention and a 16-week control period with a matched placebo.
Cognitive performance measurement by Cambridge Neuropsychological Test Automated Battery
Cognitive performance will be investigated using Cambridge Neuropsychological Test Automated Battery (CANTAB), which will be performed on an Ipad. The cognitive task performance will be tested in three important cognitive domains namely attention, memory and executive function. Learning effects are prevented by randomization of the intervention periods and the settings of CANTAB, including parallel modes and stimuli randomization. The test will be performed in Dutch.
Time frame: Change in cognitive performance at the end of a 16-week wild blueberry intervention and a 16-week control period with a matched placebo.
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 wild blueberry intervention and 16-week control period with a matched placebo.
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