People who report subjective memory complaints have a greater risk of developing dementia. Memory issues may be an early warning sign of dysfunctional cerebral glucose metabolism and cerebral blood flow. Interventions that can restore cerebral metabolism and enhance cerebral blood flow may protect against conversion to dementia. Exogenous ketone supplements have been shown rapidly improves brain network function in young adults. Further, infusion studies demonstrate that ketone bodies enhance cerebral blood flow in cognitively normal adults. Whether acute ketone monoester supplementation can improve brain function in adults with subjective memory complaints is currently unknown.

This study will investigate the effects of a single ketone monoester dose on resting-state functional connectivity in the default mode network and resting cerebral blood flow in adults with subjective memory complaints.

Inclusion Criteria:

• between the ages of 55 and 70
• presence of subjective memory complaints as determined by the Prospective- Retrospective Memory Questionnaire
• cognitively normal, e.g. score ≥26 on the Montreal Cognitive Assessment

Exclusion Criteria:

• Presence of obesity (body mass index > 30 kg/m^2)
• Presence of known cardiovascular disease
• Presence of type 2 diabetes
• History of cardiovascular events requiring hospitalization in the past 3 years (e.g., heart attack, stroke)
• History of concussion(s) with persistent symptoms
• Currently following a ketogenic diet and/or taking ketone body supplements
• Diagnosis of any form of Alzheimer's disease or dementia

The investigators will share individual patient data (de-identified) with researchers upon request.

Beginning 9 months and ending 36 months following article publication.

Anyone who wishes to access the data.