A randomized crossover trial found that a daily serving of unsalted, skin-roasted peanuts led to measurable increases in brain blood flow and modest gains in verbal memory in healthy adults aged 60 to 75, while also nudging down some blood pressure measures; the study used MRI to track cerebral perfusion, tested cognition, noted specific nutrients in peanuts that support vascular function, and flagged limits like the small sample size and short duration.
Researchers enrolled older volunteers and asked them to alternate between two 16-week periods: one where participants ate 60 grams of unsalted, skin-roasted peanuts every day, and another where they avoided peanuts entirely, with an eight-week break between phases. The order was randomized so each person served as their own control, which tightens comparisons even when numbers are small. Scans and tests were repeated throughout to capture any changes over time.
Specialized MRI scans showed a 3.6% overall increase in cerebral blood flow after the peanut-eating period, with particularly notable rises in the frontal and temporal lobes—regions tied to reasoning, language and memory. Gray matter regions that handle emotion and decision-making also registered slightly stronger improvements. The team linked these imaging changes with modest gains in verbal memory performance, roughly a 5.8% uptick on the tests used.
“[Cerebral blood flow] is an important physiological marker, because having a strong flow of blood to the brain contributes to its health,” Peter Joris, Ph.D., the study’s author and an associate professor in the Department of Nutrition and Movement Sciences at the Maastricht University Medical Center, said. He also noted, “We found that longer-term consumption of unsalted, skin-roasted peanuts improved global cerebral blood flow, which suggests an overall enhancement in brain vascular function.” These lines underline that the authors view blood flow as a practical indicator of brain vascular health.
Not everything moved in the same direction: tests of executive function and reaction speed did not show meaningful change, suggesting the benefits were selective rather than universal. There were small decreases in systolic blood pressure and pulse pressure, hinting at broader vascular advantages beyond the brain. Because the improvements concentrated in memory-related areas and verbal tasks, the effect appears linked to particular cognitive systems rather than global sharpening.
Nutritionally, peanuts pack a mix of elements known to support blood vessels: unsaturated fats, plant protein, fiber, polyphenols and amino acids like L-arginine. “Peanuts are especially rich in plant-based protein and contain high concentrations of L-arginine, an amino acid important for vascular health,” Joris wrote. The skin-roasted preparation also means extra antioxidant intake from the peanut skins, which may have played a role in the observed outcomes.
There are clear caveats. The sample was small and composed of healthy older adults, so these findings may not generalize to younger people or those with chronic health conditions. The study tested a single form and amount of peanuts—unsalted, skin-roasted at 60 grams per day—so different preparations or smaller portions might produce different results. Participants probably knew when they were eating peanuts, which opens the door to placebo influences on subjective measures.
Calorie density is another practical concern: peanuts are energy-rich, so nutritionists advise balancing servings with lean proteins, vegetables, fruits and whole grains and favoring unsalted or lightly salted varieties. The trial was short-term, meaning it cannot tell us whether the vascular and memory changes persist or translate into lower dementia risk long term. The published report also noted funding support from The Peanut Institute Foundation but stated that the funder did not influence the study design or interpretation of the data.
