Background: The ketogenic diet (KD) has gained interest as a potential therapy for numerous conditions; however, studies rarely report the food and micronutrient profile of the diet.
Objective: The aim of this study was to report changes in food selection and nutritional quality from the baseline diet (BD) to a KD therapy in participants with Alzheimer disease (AD).
Methods: Fifteen AD patients participated in a single-arm clinical trial to assess the feasibility of a 3-mo KD intervention. A registered dietitian instructed participant study partners to assist participants with a self-selected, nutritionally dense KD. We collected food and nutrient intake via monthly 3-d food records. Serum β-hydroxybutyrate was measured within 48 h of each 3-d food record to assess ketosis status. Food records before KD initiation characterized the BD. Food records during the intervention coincident with the most robust ketosis characterized the KD. Principal components analysis identified foods affiliated with the BD and KD. Mean food and nutrient intake change was tested by the Kruskal-Wallis test for variance with significance set at P ≤ 0.025.
Results: Ten participants adhered to the KD. Study partners provided complete food records for 6 KD-adherent individuals. The KD was characterized by increased medium-chain triglyceride (MCT) oil, nonstarchy vegetables, butter, eggs, olive oil, avocados, and nuts and seeds with practical elimination of potatoes, grains, red meat, sugar-sweetened beverages, and desserts. Fruit intake, including avocado, was similar between diets. Nonstarchy vegetable intake increased from 1.2 servings/d to 4.3 servings/d (P < 0.01) on the KD. Micronutrient intake was similar between diets, meeting Dietary Reference Intakes for most nutrients. Between diets, the KD was associated with increased intake of choline and vitamin K and decreased intake of manganese and fiber.
Conclusion: As a potential therapy in AD, the KD can be nutritionally dense with high intake of vegetables and substantial variety. This trial was registered at clinicaltrials.gov as NCT03690193.
Keywords: Alzheimer disease; fruits; ketogenic diet; principal components analysis; vegetables.