Healthy diets may improve brain health in older adults living with obesity

A new study led by the National Institute on Aging (NIA) suggests that older adults living with obesity and metabolic issues can boost their brain health by following a healthy diet.

Published in Cell Metabolism, the research highlights how dietary interventions may slow brain aging and improve cognitive function in this population.

The study compared the effects of two diets—intermittent fasting and the USDA healthy living diet—on 40 participants, aged 63 on average, who were insulin resistant. Insulin resistance, which impairs the body’s ability to regulate glucose, has been linked to an increased risk of developing Alzheimer’s disease and related dementias.

Participants were randomly assigned to either a 5:2 intermittent fasting diet, restricting calories to 25 per cent of their daily intake for two days a week, or the USDA healthy living diet, rich in fruits, vegetables, whole grains, lean proteins, and low-fat dairy. The goal was to determine if these diets could improve insulin sensitivity and cognitive health.

Over the eight-week study, scientists collected blood samples to analyse neuron-derived extracellular vesicles, small fragments of neurons that can indicate how well the brain is using insulin. Cognitive tests and brain scans, including magnetic resonance imaging, were also conducted to assess brain aging and glucose usage. Additionally, the researchers looked for Alzheimer’s biomarkers in the cerebrospinal fluid.

Both diets were found to slow brain aging and improve cognition and insulin resistance. The intermittent fasting group showed even greater improvements in executive function and experienced more weight loss than those on the USDA diet. However, neither diet significantly impacted Alzheimer’s biomarkers.

While the study did not find direct effects on dementia risk, the results indicate that diet can play an important role in supporting brain health in older adults with metabolic challenges. This research offers a foundation for further clinical trials exploring dietary interventions to improve brain function in aging populations.