Associations between Diet and Cognitive Function in Stroke Survivors: A Systematic Review and Meta-analysis

Poststroke cognitive decline is a major form of disability in stroke survivors. Although dietary interventions have shown potential in improving cognitive outcomes in stroke-free populations, their effects on stroke survivors remain unclear. This review aimed to evaluate associations between diet and cognitive function in stroke survivors. MEDLINE, Embase, Scopus, and CINHAL were searched for studies from inception to 16 December, 2024. Eligible articles were observational and interventional studies on adult stroke survivors that evaluated the association/effect of any nutritional exposure/intervention on cognitive performance and dementia risk. Studies were excluded when an intervention was combined with nonnutritional treatment. Random-effects meta-analysis was used for similar randomized clinical trials. This review included 20 clinical trials and 14 observational studies assessing the intake of energy and proteins and a variety of single nutrients, as well as dietary patterns, single foods, and phytochemicals. Meta-analyses revealed a positive effect of energy-protein supplementation on global cognition [standardized mean difference (SMD): 0.62; 95% confidence interval (CI): 0.15, 1.08; P = 0.009], and a negative effect of B-vitamins (folic acid, vitamin B6, and vitamin B12) (SMD: -0.40; 95% CI: -0.72, -0.08; P = 0.02). Adherence to the Mediterranean-Dietary Approaches to Stop Hypertension (DASH) Intervention for Neurodegenerative Delay and plant-based diets, as well as higher consumption of fruits, milk, coffee, vitamin E, and selenium, were related to better cognitive outcomes; no significant association was observed for adherence to DASH and Mediterranean diets and consumption of vitamins D and C. Butter and sugar intake and calcium supplementation were associated with negative cognitive outcomes. Mixed results were seen for omega (ω)-3, tea, and plant extracts. The available evidence indicates that energy-protein supplementation may benefit cognition after stroke, whereas B-vitamin supplementation has no effect. The substantial heterogeneity among studies hinders conclusions about other dietary strategies. This review was registered with PROSPERO as CRD42024541785.