Healthy dietary patterns, cognition and dementia risk: current evidence and context.

Approximately 60 million individuals worldwide are currently living with dementia. As the median age of the world's population rises, the number of dementia cases is expected to increase markedly, and to affect ∼150 million individuals by 2050. This will create a huge and unsustainable economic and social burden across the globe. Although promising pharmacological treatment options for Alzheimer's disease - the most common cause of dementia - are starting to emerge, dementia prevention and risk reduction remain vital. In this review, we present evidence from large-scale epidemiological studies and randomised controlled trials to indicate that adherence to healthy dietary patterns could improve cognitive function and lower dementia risk. We outline potential systemic (e.g. improved cardiometabolic health, lower inflammation, modified gut microbiome composition/metabolism, slower pace of aging) and brain-specific (e.g. lower amyloid- load, reduced brain atrophy and preserved cerebral microstructure and energetics) mechanisms of action. We also explore current gaps in our knowledge and outline potential directions for future research in this area. Our aim is to provide an update on current state of the knowledge, and to galvanise research on this important topic.