Researchers at Maastricht University Medical Center in the Netherlands report that eating about 60 grams of unsalted, skin-roasted peanuts daily for 16 weeks improved insulin responsiveness in brain regions critical for memory, including parts of the hippocampus, lingual gyrus, parahippocampal gyrus and posterior cingulate gyrus.

The findings, published in the peer-reviewed journal Food & Function, come from a randomized, controlled crossover trial of 31 healthy adults aged 60 to 75.

Senior author Dr. Peter Joris says the brain may become less responsive to insulin with age, a change linked to age-related cognitive decline, and that enhanced regional brain insulin responsiveness may contribute to the cognitive benefits of daily peanut intake.

Insulin is best known for regulating blood sugar, but it also helps nerve cells grow, survive and communicate, supporting memory and possibly protecting against processes associated with Alzheimer's disease.

That a simple, inexpensive snack could measurably change insulin signaling in memory-related brain regions is a striking result for nutrition research.

The study, led by principal investigator Dr. Peter J. Joris and conducted by Ph.D. candidate Lucia Kerkhof, was funded by The Peanut Institute Foundation, which the researchers say had no role in designing or conducting the study, analyzing the results, or preparing the manuscript.

The team used arterial spin labeling MRI (ASL-MRI) to track regional cerebral blood flow after insulin was administered through the nose, alongside abdominal MRI scans of liver fat and the CANTAB battery of computerized cognitive tests.

Participants received premeasured packets of skin-roasted peanuts to eat in the morning or afternoon, either all at once, in divided portions, or with meals, then switched to a peanut-free control phase.

Science Daily also reports an earlier 2025 study by Joris, published in Clinical Nutrition, that found 16 weeks of peanut consumption raised overall cerebral blood flow by 3.6% and improved verbal memory performance by 5.8%.

The New York Post reports that researchers credit multiple nutrients in peanuts rather than any single compound, including unsaturated fats, dietary fiber, vitamins, minerals and bioactive phytochemicals, plus L-arginine, an amino acid precursor of nitric oxide that has been reported to facilitate learning and memory.

For now, the work positions a common legume as a promising subject for further research into diet and cognitive decline.