Brain responses to intermittent fasting and the healthy living diet in older adults.
Level 2 - randomized trial
Individual randomized controlled trial in older adults with insulin resistance
PubMed 38901423 · doi:10.1016/j.cmet.2024.05.017
What was done
An 8-week randomized clinical trial in 40 cognitively intact older adults with insulin resistance evaluated the effects of 5:2 intermittent fasting compared to a healthy living diet. Outcomes included weight loss, insulin signaling biomarkers in neuron-derived extracellular vesicles, magnetic resonance imaging measures of brain biological age (brain-age-gap estimate), magnetic resonance spectroscopy of brain glucose, blood metabolic markers, cerebrospinal fluid biomarkers for Alzheimer's disease, and cognitive testing (executive function and memory).
What was found
The abstract reports no exact numerical values or effect sizes. Intermittent fasting led to greater weight loss than the healthy living diet. Both diets had comparable beneficial effects on improving neuron-derived extracellular vesicle insulin signaling biomarkers, reducing MRI-derived brain-age gap, lowering MRS brain glucose, improving blood carbohydrate and lipid markers, and enhancing executive function and memory (with intermittent fasting showing greater benefit on certain cognitive measures). Minimal changes were detected in cerebrospinal fluid biomarkers of Alzheimer's disease.
Why it matters
This trial demonstrates that dietary interventions targeting metabolic health can directly improve markers of brain aging, neural insulin sensitivity, and cognitive performance in at-risk older adults.
Limits
The sample size was small (n = 40) and the intervention duration was brief (8 weeks). The abstract does not provide exact numeric data, confidence intervals, or specific cognitive test scores. Generalizability is limited to cognitively intact older adults with baseline insulin resistance.