Evidence for Improved Cognitive Health with Diet: A Narrative Review

Despite growing interest in nutrition as a behavioral intervention to improve cognitive health in clinical populations, many providers find it challenging to provide specific nutritional recommendations. We aimed to review and synthesize current empirical research on this topic and provide considerations for healthcare providers working with adults who wish to optimize their cognition via dietary improvements.

We performed a narrative review of research published between January 2009 and May 2021 on 5 popular dietary interventions: the Mediterranean diet, Dietary Approaches to Stop Hypertension (DASH), the Mediterranean-DASH Intervention Diet for Neurodegenerative Delay (MIND), the ketogenic diet and intermittent fasting.

Of the 5 dietary interventions, the Mediterranean diet has been the most extensively investigated, and there is evidence supporting its cognitive benefits. However, operationalization of the Mediterranean diet varies across studies, rendering the results inconclusive. The DASH diet and the MIND diet have stronger operationalization and showed evidence of cognitive benefits. More longitudinal studies and/or randomized clinical trials should be conducted on these 2 relatively new interventions. Finally, there is limited research with human participants regarding the ketogenic diet and intermittent fasting, which are found to be cognitively protective within stringent parameters. Definitions for these 5 dietary patterns and practice tips and recommendations are provided.