A small trial of 31 healthy adults aged 60 to 75 found that eating 60 grams of unsalted, skin-roasted peanuts daily for 16 weeks improved insulin responsiveness in memory-related brain regions. The study did not show that peanuts prevent dementia or Alzheimer's disease.
A small new study in the journal Food & Function found that daily consumption of unsalted, skin-roasted peanuts beneficially affected insulin responsiveness in memory-related brain regions in older adults. The researchers were from Maastricht University Medical Center in the Netherlands, and they examined how regular peanut consumption affects the brain's response to insulin with advancing age. Eating 60 grams of the peanuts daily for 16 weeks improved insulin responsiveness in brain regions involved in memory among adults aged 60 to 75.
How the trial worked
The randomized, controlled crossover trial included 31 healthy adults aged 60 to 75, with an average age of around 67. Participants ate 60 grams of peanuts, about two servings, each day for 16 weeks. They ate them either in one sitting, divided throughout the day or added to meals. In a control phase, participants avoided peanuts entirely, and after 16 weeks they switched to the opposite condition. Brain measurements were compared under both dietary approaches.
Insulin was administered through the nose, and regional cerebral blood flow was measured with arterial spin labeling magnetic resonance imaging. The team also assessed cognitive performance using the Cambridge Neuropsychological Test Automated Battery.
What the researchers found
After 16 weeks of daily peanut consumption, researchers observed improved insulin responsiveness in a group of right-hemisphere brain regions. These included portions of the hippocampus, parahippocampal gyrus, lingual gyrus and posterior cingulate gyrus. Researchers found no improvement in executive function or in measures of processing speed.
Senior author Dr. Peter Joris said the brain may become less responsive to insulin as people age, which has been linked to age-related cognitive decline. He said several nutrients in peanuts, including unsaturated fats, fibre, vitamins, minerals and bioactive phytochemicals, could potentially contribute to the observed benefits. Joris also said peanuts are especially rich in L-arginine, a key precursor of nitric oxide, which has been reported to facilitate learning and memory performance.
An earlier study by the same group, published in Clinical Nutrition in 2025, reported a 3.6% increase in overall cerebral blood flow and a 4.5% increase in grey matter blood flow. It also reported a 5.8% improvement in delayed verbal memory recall compared with control, while executive function and psychomotor speed showed no significant benefits.
Limits and funding
The study did not establish that eating peanuts prevents dementia or Alzheimer's disease, nor that peanuts reverse existing memory problems. The researchers did not demonstrate that peanuts prevent cognitive decline or stop dementia from developing. The study was limited to 31 people, and its small sample and focus on healthy older adults limit how widely the findings can be applied. Researchers say nutrients in peanuts may support brain health, but further research is needed to establish whether they can help prevent Alzheimer's disease.
The 2026 research was funded by The Peanut Institute Foundation. The researchers stated the foundation had no involvement in study design, conduct, analysis, interpretation or manuscript preparation.
