Aronia melanocarpa extract supplementation affects brain vascular function and cognitive performance: A randomized, double-blind, placebo-controlled, cross-over study in older adults with overweight or obesity

BACKGROUND AND AIMS: Dietary anthocyanins are recognized for their potential beneficial effects on cognitive performance. It remains unclear which mechanisms underlie these effects. This study aimed to investigate the effects of anthocyanin-rich Aronia Melanocarpa extract (AME) on (brain) vascular function and cognitive performance in adults at increased risk of cognitive impairment. METHODS: ) were included in a randomized, double-blind, placebo-controlled cross-over study of 6 weeks (40 mg anthocyanins/day). At the end of each study period, cerebral blood flow (CBF), a marker of brain vascular function, was assessed using arterial spin labeling magnetic resonance imaging (ASL-MRI). Additionally, cognitive performance was assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB), cerebral perfusion with transcranial Doppler ultrasound, and peripheral vascular function through endothelial function and retinal microvascular caliber measurements. RESULTS: AME supplementation did not affect CBF in predefined brain regions, but regional CBF decreased in one cluster located in the right insular cortex (treatment effect 4.4 ± 3.6 mL/100 g/min; p = 0.004), compared to placebo. Furthermore, cognitive performance was improved on the spatial working memory test, reflecting the executive function domain as the between errors and total errors were reduced by 20 % (-3; 95 % CI: -5 to -1; p = 0.006). Memory and psychomotor speed did not change, while cerebral perfusion and peripheral vascular function measurements were also not affected. CONCLUSIONS: Six weeks of AME supplementation improved executive functioning in older adults with overweight or obesity. Although CBF decreased in the right insular cortex, the relevance remains unclear. CBF in predefined brain regions and other potential underlying mechanisms were not affected.. CLINICAL TRIAL REGISTRY: This trial was registered at clinicaltrial.gov as NCT05268133.