ABSTRACT
Introduction: Ketogenic diet (KD) therapy has been used as a dietary intervention in drug-resistant epilepsy for several years. Research currently suggests that KD therapy may carry neuroprotective and cognition enhancing effects for individuals with non-epileptic conditions as well as for healthy individuals. Therefore, KD may have potential as a non-invasive, nutritional treatment approach for difficult to manage conditions such as neurodegenerative illnesses or mood disorders. The aim of this review is to summarize the available evidence on ketogenic interventions and the resulting cognitive outcomes. Materials and Methods: The paper was based on PRISMA 2020 guidelines. The search was conducted in June 2021 on the following databases: CENTRAL, PubMed, EMBASE, PsycInfo, Web of Science. The search yielded 2014 studies, of which 49 were included. Results: There were 22 animal studies assessing murine models and 27 studies on humans. The primary indications in these studies were epileptic conditions, neurodegenerative disorders, cognitive impairment, and healthy populations. Discussion: Administration of KD seems to confer cognitive-enhancing effects in areas such as working memory, reference memory and attention. Studies found that KD treatment in animals has the potential to alleviate age-related cognitive decline. Over 80% of the 27 human studies reported a favourable effect of intervention, and none reported a detrimental effect of KD. While these findings suggest that KD may improve the functioning of certain cognitive domains, definitive conclusions were limited by studies with small sample sizes, the absence of controls and randomization, and the lack of objective measures of cognition.
Disclosure statement
Jennifer Fabe is a practicing registered dietitian in ketogenic diet therapy at Hamilton Health Sciences and clinical director and co-developer of the KetoSuite digital application tools. No potential conflict of interest was reported by the other author(s).
Additional information
Notes on contributors
Arun Chinna-Meyyappan
Arun Chinna-Meyyappan is a recent graduate from the Life Sciences Honours Program at Queen’s University and is currently a graduate student in Neuropharmacology at the University of Toronto. His study interests include biomarkers of neurodegenerative and mood disorders, the use of controlled substances including cannabinoids and psychedelics to address neurological conditions, and the influence of dietic interventions on mental functioning.
Fabiano Alves Gomes
Fabiano Alves Gomes is a psychiatrist and clinician-scientist currently working as an Assistant Professor in the Department of Psychiatry and Behavioural Neurosciences at McMaster University. He studies the interface between mood disorders and metabolic abnormalities to better understand underlying disease processes and develop innovative interventions.
Elena Koning
Elena Koning is a doctoral student studying neuropsychiatry at the Centre for Neuroscience Studies at Queen’s University. She is exploring eating behavioral phenotypes and eating rhythm dysfunction in individuals with mood disorders as well as novel tools for treatment, such as psilocybin-assisted psychotherapy.
Jennifer Fabe
Jennifer Fabe is a registered dietitian currently working in the Department of Pediatric Neurology at Hamilton Health Sciences. Her interest includes the application of medically supervised ketogenic diet therapy in brain based diseases. She also studies practical boundaries to successful implementation and is an innovator of approaches to support sustainable medical ketogenic diet therapy.
Vitor Breda
Vitor Breda is a psychiatrist and researcher currently working as a Postdoctoral Fellow in the Department of Psychiatry at Queen’s University. His studies include the investigation of neurodevelopmental trajectories of ADHD across the lifespan and the impact of nutrition in mental health.
Elisa Brietzke
Elisa Brietzke is a psychiatrist and neuroscientist currently working as Full Professor in the Department of Psychiatry at Queen’s University. She develops studies on innovative treatments for depression and bipolar disorders and currently serves as the co-lead of the International Society of Bipolar Disorder Nutrition and Exercise Task Force.