Eating two daily servings of unsalted, skin-roasted peanuts improves how specific memory-related regions in the right hemisphere of the aging brain respond to insulin, according to a clinical trial published in the peer-reviewed journal Food & Function. Researchers at Maastricht University Medical Center in the Netherlands found that the dietary intervention altered regional brain insulin responsiveness in older adults over a 16-week period.
While insulin is primarily known for regulating blood sugar, the hormone also facilitates learning, memory, and communication between nerve cells. As people age, the brain often becomes less sensitive to insulin, a physiological shift linked to cognitive decline, according to Dr. Peter Joris, senior study author and associate professor in the Department of Nutrition and Movement Sciences at NUTRIM, Maastricht University Medical Center.
How Maastricht University Researchers Tested Daily Peanut Consumption
The trial examined 31 healthy adults ranging in age from 60 to 75 years old. Using a randomized, controlled crossover design, researchers supplied participants with premeasured packets containing 60 grams of skin-roasted, unsalted peanuts daily for 16 weeks. Participants could eat the daily allotment in a single sitting, divide the amount throughout the day, or incorporate the peanuts into meals, before switching to a control phase that excluded peanuts entirely.
To measure brain function changes, the investigative team administered insulin through the nose and used arterial spin labeling magnetic resonance imaging (ASL-MRI) to track shifts in regional cerebral blood flow. They also utilized abdominal MRI scans to measure intrahepatic lipid accumulation and assessed cognitive performance via the Cambridge Neuropsychological Test Automated Battery (CANTAB).
Right Hemisphere Brain Regions Showing Enhanced Insulin Responsiveness
Following the 16-week dietary phase, researchers observed enhanced insulin responsiveness clustered within a specific group of brain regions located in the right hemisphere. These areas included portions of the hippocampus, the parahippocampal gyrus, the lingual gyrus, and the posterior cingulate gyrus.
Each of these structures contributes directly to memory processes and related cognitive functions. The investigative team emphasized that while the trial identified changes in regional brain sensitivity to insulin, the data did not demonstrate that eating peanuts actively prevents cognitive decline or halts the development of dementia.
Nutritional Compounds and Prior Cerebral Blood Flow Findings
The new findings build directly upon earlier research published by Joris and colleagues in 2025 in the journal Clinical Nutrition. That prior investigation established that a 16-week peanut intervention increased overall cerebral blood flow by 3.6% and improved verbal memory performance by 5.8%.
Researchers attribute these physiological effects to a combination of nutritional components rather than a single isolated nutrient. Peanuts provide unsaturated fats, dietary fiber, vitamins, minerals, and bioactive plant compounds, as well as plant protein. Joris noted that peanuts are a source of L-arginine, an amino acid the body uses to produce nitric oxide, which helps regulate blood vessel function and may in turn be linked to learning and memory processes.
Frequently Asked Questions About the Maastricht University Peanut Study
Did the study prove that eating peanuts prevents Alzheimer’s disease?
Researchers observed improved insulin responsiveness in specific memory-related brain regions among healthy adults aged 60 to 75, but the study did not demonstrate that peanuts prevent Alzheimer’s or stop dementia from developing.
Who funded the research published in Food & Function?
The study was supported by funding from The Peanut Institute Foundation. According to the research team, the foundation had no involvement in study design, implementation, data analysis, result interpretation, or manuscript preparation.
How much peanuts did participants consume during the trial?
Participants consumed 60 grams, which equals approximately two servings of unsalted, skin-roasted peanuts each day for the duration of the 16-week intervention period.
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