Keto plus fasting held cognition steady in Alzheimer's

Standard treatment for Alzheimer's disease slows symptoms at best, and interest has grown in metabolic approaches on the argument that the ageing brain may use ketones when glucose handling falters. Ketogenic diets and intermittent fasting have each been floated as adjuncts, but they are usually tested separately, in short studies, and often in mild cognitive impairment rather than established disease. There is also a nutritional objection to conventional ketogenic diets in older adults, which this study addresses by using a plant-rich version. The trial asked whether combining the two, tailored to the individual and added on top of usual care, changes the trajectory of cognition.

This was an assessor-blinded randomised controlled trial enrolling 60 patients with Alzheimer's disease staged at CDR 1 to 2 and aged 55 to 85 years. Participants were randomised to an intervention group of 30, who received the individualised plant-rich ketogenic diet with intermittent fasting alongside standard care, or a control group of 30 receiving standard care alone. Cognition and brain structure were assessed at baseline and again at six months. Alongside conventional group comparisons, the researchers analysed each participant's change using the Reliable Change Index, a method that classifies whether an individual's score has genuinely improved, remained stable or declined beyond measurement error.

Cognitive change scores differed significantly between the groups (p less than 0.001). Mean Mini Mental State Examination score rose by 0.9 points in the intervention group while falling by 1.5 points in the control group over the six months. The Reliable Change Index analysis, which looks at individuals rather than averages, classified 93% of intervention participants as stable compared with 70% of controls, with cognitive improvement in 7% and 3.3% respectively. The authors add that response to the intervention was closely related to each person's metabolic phenotype and structural brain integrity, indicating the effect was not uniform across participants.

The result is consistent with the broader hypothesis that metabolic interventions can influence cognitive trajectory in Alzheimer's disease, and the use of a plant-rich ketogenic pattern addresses a common nutritional criticism of classic keto protocols. But the design leaves several things unresolved: the control group received standard care without any comparable dietary attention, so expectation and contact effects cannot be excluded, and the combination of diet and fasting means neither component can be credited individually. The magnitude is also modest, amounting to a divergence of a few points on a brief screening test. Longer trials with active dietary controls and clinically meaningful endpoints are the obvious next step.

This is a reason to think that diet-based adjuncts deserve serious testing in Alzheimer's disease rather than dismissal, and that stability — not decline — may be a realistic thing to measure over six months. It is not evidence that a ketogenic diet reverses dementia, and the improvement seen was small and measured on a screening instrument. The authors' observation that response depended on metabolic phenotype and brain structure suggests such approaches would not suit everyone equally. Anyone considering major dietary change in the context of a neurological diagnosis is in medical territory, and this single trial does not settle it.