Researchers at Maastricht University Medical Center in the Netherlands found that eating 60 grams of unsalted, skin-roasted peanuts daily for 16 weeks improved insulin responsiveness in memory-related brain regions of older adults. The study, conducted by Associate Professor Dr. Peter J. Joris and Ph.D. candidate Lucia Kerkhof and published in Food & Function, involved 31 healthy adults aged 60 to 75 using a randomized, controlled crossover trial design.
The improved insulin responsiveness appeared in the right hemisphere, specifically in portions of the lingual gyrus, hippocampus, parahippocampal gyrus, and posterior cingulate gyrus. These regions contribute to memory-related processes. "As people age, the brain may become less responsive to insulin, which has been linked to age-related cognitive decline," Joris said. "Our study found that daily peanut consumption beneficially affected insulin responsiveness in memory-related brain regions in older adults."
Insulin plays multiple roles in the brain beyond blood sugar regulation. It helps nerve cells grow, survive, and communicate with one another, supporting memory and other cognitive abilities. Healthy insulin signaling may help protect against processes associated with Alzheimer's disease.
Researchers used arterial spin labeling magnetic resonance imaging (ASL-MRI) to measure blood flow in different brain regions and tracked insulin responsiveness by monitoring changes in regional cerebral blood flow after insulin was administered through the nose. They also measured liver fat accumulation and assessed cognitive abilities using the Cambridge Neuropsychological Test Automated Battery (CANTAB).
Earlier research by Joris published in 2025 found that peanut consumption for 16 weeks increased overall cerebral blood flow by 3.6% and improved verbal memory performance by 5.8%. Results from that investigation appeared in Clinical Nutrition.
Joris noted that multiple peanut components likely contribute to the observed effects. "Multiple nutrients present in peanuts, including unsaturated fats, dietary fiber, vitamins and minerals and bioactive phytochemicals, could potentially contribute to the observed brain benefits," he said. "Peanuts are also a good source of plant-based protein and are especially rich in L-arginine. L-arginine is a key precursor of nitric oxide (NO), which has been reported to facilitate learning and memory performance."
During the study, participants received premeasured packets of skin-roasted peanuts and consumed them in the morning or afternoon at their discretion. They could eat the entire portion at once, divide it into smaller amounts, or include the peanuts in their meals. During the control phase, participants avoided peanuts entirely.
The Peanut Institute Foundation provided funding. According to the researchers, the foundation had no involvement in designing or conducting the study, analyzing or interpreting results, or preparing the manuscript.