Review: Ketogenic Diet Tied to Slightly Better Cognition in Older Adults with Impairment
A systematic review with meta-analysis pooled twelve randomised trials with 707 older adults with mild cognitive impairment or Alzheimer's disease. Ketogenic diets slightly improved overall cognition, mainly memory and language. Total and LDL cholesterol rose at the same time.
1. What the Research Says
The review covered the ketogenic diet and related ketogenic eating strategies, with seven databases searched up to July 2025. The effect on overall cognition was small (standardised mean difference 0.34). Attention and executive function, meaning planning and controlling one's own actions, did not improve. Blood levels of the ketone bodies acetoacetate and beta-hydroxybutyrate rose, so the diet had the intended metabolic effect. Triglycerides and HDL cholesterol did not change. The authors declare no conflicts of interest.
2. How It Fits Earlier Research
Two earlier reviews reached a similar result. Ten trials in Alzheimer's disease showed better scores in memory and thinking tests, but also higher triglycerides and higher LDL cholesterol (2024). Ten trials in Alzheimer's disease and mild cognitive impairment found better overall cognition, but no effect on attention or executive function (2020). Effects of ketogenic diet on cognitive function of patients with Alzheimer's disease: a systematic review and meta-analysis. (2024) · To Keto or Not to Keto? A Systematic Review of Randomized Controlled Trials Assessing the Effects of Ketogenic Therapy on Alzheimer Disease. (2020)
3. Source
Full evidence overview: Ketogenic Diet
Every statement on this page carries its evidence tier — proven, plausible or hypothesis — and leads to the original work. The decision in the individual case rests with the practitioner; we provide the connections.