Daily consumption of unroasted, skin-roasted peanuts improves brain insulin sensitivity and regional blood flow in older adults, according to a Maastricht University Medical Center study published in Food & Function.
Maastricht University Medical Center Study Tests 31 Older Adults Over 16 Weeks
Researchers examined 31 healthy adults aged 60 to 75 in a randomized, single-blind, controlled crossover trial. Participants consumed 60 grams of unrefined, skin-roasted peanuts daily for 16 weeks, alongside a control period without the snack. Scientists administered insulin intranasally to track how regional cerebral blood flow shifted across specific brain networks, utilizing arterial spin-labeling magnetic resonance imaging (ASL-MRI).
The intervention altered how brain regions responded to insulin, particularly within areas of the right hemisphere that govern memory formation, including the hippocampus. The trial also built on previous findings, which linked a four-month peanut intervention to a 3.6 percent increase in total cerebral blood flow and a 5.8 percent improvement in verbal memory.
Insulin Signaling and Vascular Function in Aging Brains
As people age, the brain often becomes less responsive to insulin, a physiological shift tied to cognitive decline, noted Dr. Peter Joris, study author at Maastricht University Medical Center. In the central nervous system, insulin acts as a key signaling molecule that supports neuron survival, learning, and synaptic communication.
Peanuts provide a complex profile of unsaturated fats, dietary fiber, vitamins, minerals, and plant protein. Researchers have not yet isolated which specific nutrient drives the response, nor whether alternative culinary preparations yield identical physiological changes. Furthermore, the 16-week observation window remains too brief to establish long-term prevention of neurodegenerative diseases such as Alzheimer’s, and the small cohort of 31 healthy participants limits broader clinical extrapolation.
Frequently Asked Questions About Daily Peanut Consumption
Why did researchers deliver insulin through the nose during the trial?
This method allowed the Maastricht University Medical Center team to measure localized vascular and metabolic responses using ASL-MRI.
Do commercially salted or honey-roasted peanuts produce the same physiological effects?
The study evaluated strictly unrefined, skin-roasted peanuts without added sodium. Researchers have not tested whether commercial preparations containing high levels of salt, sugar, or oil alter vascular or cognitive outcomes.
What daily portion size did the clinical trial test?
Participants consumed 60 grams daily, divided into two daily portions over the 16-week intervention period. This amount corresponds to roughly two standard snack servings.