Context: In recent years, the ketogenic diet has gained special relevance as a possible therapeutic alternative to some neurological and chronic diseases.
Objective: The aim of this systematic review was to answer the following question: Does a ketogenic diet improve cognitive skills in patients with Alzheimer's disease, Parkinson's disease, refractory epilepsy, and type 1 glucose deficiency syndrome? To define the research question, the PICOS criteria were used, following the guidelines of the PRISMA method.
Data sources: Medline/PubMed, Elsevier Science Direct, Dialnet, EBSCOhost, Mediagraphic, Sage Journals, ProQuest, and Wiley Online Library databases were used.
Data extraction: After applying inclusion and exclusion criteria in accordance with the PRISMA method, a total of 63 entries published between 2004 and 2019 were used.
Data analysis: The records extracted were analyzed from a qualitative approach, so no statistical analysis was carried out.
Conclusion: Although scientific literature on the subject is scarce and there has tended to be a lack of scientific rigor, the studies reviewed confirmed the effectiveness of this diet in improving the cognitive symptomatology of the aforementioned diseases.
Keywords: Alzheimer's disease; Parkinson's disease; cognition; glucose transporter deficiency syndrome type 1; ketogenic diet; ketosis; low carbohydrate diet; refractory epilepsy; β-hydroxybutyrate.
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