A recent INC-funded study, published in Clinical Nutrition[1], showed that longer-term consumption of nuts as part of a recommended diet significantly improved brain and peripheral vascular function, and memory.
The beneficial effects of nut consumption on vascular function may underlie the improvements in cognitive performance, thereby reducing cognitive decline as a result of aging.
The clinical trial consisted of 28 healthy individuals all in their 60s. The researchers conducted a randomized, single-blinded, cross-over trial involving a 16-week intervention and control period (no nuts), separated by an 8-week washout period. The intervention consisted of 60 g per day of mixed nuts (15 g of walnuts, pistachios, cashews and hazelnuts each). Participants followed the Dutch food-based dietary guidelines.
At the end of each period, brain vascular function was measured using cerebral blood flow (CBF); peripheral vascular function was assessed using validated markers of endothelial function, arterial stiffness and the retinal microvasculature; and cognitive performance was tested in the domains of memory, executive function and psychomotor speed.
The results showed that regional CBF was higher in three areas of the brain located in the right frontal and parietal lobe, the left frontal lobe and the bilateral prefrontal cortex. Nut consumption also improved endothelial function and beneficial effects were observed on aterial stiffness and retinal microvascular calibers. Participants did not gain weight during the study. Lastly, memory was positively affected through improved performance on the paired association learning (visuospatial memory) and verbal world recognition (verbal memory) tasks.
“Based on these results we have concluded that longer-term mixed nut consumption as part of a healthy diet beneficially affected brain and peripheral vascular function in older adults, which may relate to the observed improvements in memory,” states Dr. Peter Joris, principal investigator from Maastricht University, Netherlands.
The study was supported by the INC, International Nut and Dried Fruit Council.
[1] Nijssen KMR, Mensink RP, Plat J, Joris PJ, Longer-term mixed nut consumption improves brain vascular function and memory: a randomized, controlled crossover trial in older adults, Clinical Nutrition, clinicalnutritionjournal.com.