Assessing the Role of Dark Sweet Cherry (Prunus avium L.) Consumption on Cognitive Function, Neuropeptides, and...

Background/Objectives: Obesity is linked to a higher risk of cognitive impairment. The objective of this single blind randomized trial was to evaluate the impact of dark sweet cherry (DSC) intake on cognitive function in obese adults. Methods: Participants (body mass index (BMI): 30-40 kg/m², >18 years, without chronic diseases and/or antibiotic use) consumed 200 mL of DSC drink with 3 g of cherry powder (n = 19) or an isocaloric placebo drink (n = 21) twice daily for 30 days. Cognitive function was assessed at Day 1 (D1) and Day 30 (D30) using standardized cognitive tests and the NeuroTracker (NT) 3D training program. Blood biomarkers related to cognitive health (neurotensin, substance p, and oxytocin) and circadian rhythm (melatonin and cortisol) were assessed at D1 and D30 using a Luminex multiplex bead-based immunoassay. Results: DSC supplementation significantly improved working memory and concentration, as indicated by higher scores in the digit span forward (DSF, p = 0.006) and backward (DSB, p = 0.01) tests. However, processing speed, sustained attention, and visual spatial skills, assessed through the trail making (TMT) and digit symbol substitution (DSST) tests, as well as visual cognitive performance (VCP) evaluated by the NT program, showed no significant differences between groups. Neurotensin, associated with cognitive deficits, increased in both cherry and placebo groups but was significant only in the placebo group (p = 0.007). Similarly, melatonin increased in both groups, reaching significance only in the placebo group (p = 0.02), and it correlated positively with IFNγ, suggesting a compensatory response to inflammation. Conclusions: These findings suggest DSC supplementation may enhance specific cognitive functions in obese adults. Further clinical trials are needed to confirm these results.