Eating peanuts every day may provide surprising benefits for the aging brain. Researchers at Maastricht University Medical Center in the Netherlands have found that regular consumption of unsalted, roasted peanuts with the skin can improve the response of certain brain regions to insulin in older adults. The findings come from the Nutrition and Translational Metabolism Research Institute (NUTRIM) and were published in the peer-reviewed journal Power and function.
Although insulin is best known for regulating blood sugar, it also plays a vital role in the brain. It helps nerve cells grow, survive, and communicate with each other, supporting memory and other cognitive abilities. Healthy insulin signaling may also help protect against processes associated with Alzheimer’s disease.
After participants consumed peanuts daily for 16 weeks, researchers observed improved insulin responsiveness in a group of right hemisphere brain regions. These included parts of the lingual gyrus, hippocampus, parahippocampal gyrus, and posterior cingulate gyrus, all of which contribute to memory-related processes.
“The hormone insulin plays an important role in the brain, where it supports memory and other cognitive processes. As people age, the brain may become less responsive to insulin, which has been associated with age-related cognitive decline,” explains Dr. Peter Joris, lead author of the study and associate professor at the Department of Nutrition and Movement Sciences, NUTRIM, University Medical Center Maastricht. “Our study found that daily peanut consumption had a beneficial effect on insulin responsiveness in memory-related brain regions in older adults. These results suggest that enhanced regional brain insulin responsiveness may contribute to the cognitive benefits of consuming unsalted, roasted peanuts with the skin.”
Daily Peanuts Linked to Better Memory and Cerebral Blood Circulation
The study included 31 healthy adults aged 60 to 75. During the peanut consumption phase, participants ate 60 grams (about two servings) of peanuts every day for 16 weeks. The researchers used a randomized, controlled crossover trial, a rigorous study design that allowed them to compare the effects of eating peanuts with those of avoiding them.
The new findings build on previous research by Joris published in 2025. This investigation found that consuming peanuts for 16 weeks increased overall cerebral blood flow (CBF) by 3.6% and improved verbal memory performance by 5.8%.
Cerebral blood flow measures the amount of blood flowing through the brain, carrying the oxygen and nutrients that brain cells need to function properly. It is an important indicator of the health of blood vessels in the brain. These earlier results were published in the peer-reviewed journal Clinical Nutrition.
How scientists measured the effects of peanuts on the brain
One of the distinctive features of the NUTRIM research was the combination of a carefully controlled, months-long dietary intervention and sophisticated brain imaging technology.
To examine changes in brain function, researchers used arterial spin-labeling magnetic resonance imaging (ASL-MRI), a technique that measures blood flow in different regions of the brain. They assessed insulin responsiveness by tracking changes in regional cerebral blood flow after administering insulin through the nose.
The team also used abdominal MRI scans to measure fat accumulation in the liver, known as intrahepatic lipid content (IHL). Cognitive abilities were assessed using the Cambridge Neuropsychological Test Automated Battery (CANTAB), a standardized collection of computerized tests.
Researchers believe that multiple components of peanuts may contribute to their observed effects on brain health, rather than a single nutrient being responsible.
“Many nutrients found in peanuts, including unsaturated fats, dietary fiber, vitamins, minerals, and bioactive phytochemicals, could potentially contribute to the observed brain benefits,” says Joris. “Peanuts are also a good source of plant protein and are particularly rich in L-arginine. L-arginine is a key precursor of nitric oxide (NO), which is thought to facilitate learning and memory performance.”
What participants ate during the 16-week study
To ensure that participants consumed a consistent amount, researchers provided pre-measured packets of roasted peanuts with the skin on throughout the peanut intervention period.
Participants were instructed to eat their peanuts in the morning or afternoon, but they could choose how to incorporate them into their daily routine. They could eat the entire serving at once, divide it into smaller amounts throughout the day, or include the peanuts in their meals.
During the control phase, participants avoided peanuts completely. After 16 weeks, they switched to the opposite study conditions, allowing the researchers to compare measures of brain health under the two dietary approaches.
The study was led by Principal Investigator Associate Professor Dr. Peter J. Joris and conducted by Ph.D. candidate Lucia Kerkhof from the Department of Nutrition and Movement Sciences at the University Medical Center of Maastricht.
Funding was provided by the Peanut Institute Foundation. According to the researchers, the foundation was not involved in the design or conduct of the study, nor in the analysis or interpretation of the results, nor in the preparation of the manuscript.
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