A Handful of Peanuts, a Hint of Better Memory?

Key takeaways

• In a randomized crossover study of 31 adults ages 60–75, eating 60 grams of unsalted, skin-roasted peanuts daily for 16 weeks improved insulin responsiveness in specific brain regions involved in memory.

• An earlier report from the same trial found improved brain blood flow and a modest benefit on one verbal memory task—not improvements across all thinking skills.

• The findings suggest a possible connection between peanuts, brain insulin signaling, and memory. They do not prove lasting cognitive benefits or slower brain aging.

• This was a small, short trial. Larger, independent studies are needed to confirm the results.

A familiar food, a different question

Insulin does more than regulate blood sugar. In the brain, it also supports communication between nerve cells and processes involved in learning and memory.

Researchers at Maastricht University Medical Center asked whether eating peanuts regularly could change how the aging brain responds to that signal.

Thirty-one healthy older adults completed two 16-week periods: one eating 60 grams of unsalted, skin-roasted peanuts daily and another avoiding peanuts. An eight-week break separated the periods, allowing researchers to compare each person’s results under both conditions.

A response in memory-related regions

Researchers delivered insulin through the nose and used specialized MRI scans to measure changes in regional brain blood flow.

After the peanut period, insulin responsiveness improved in a cluster of regions on the right side of the brain, including parts of the hippocampus and nearby areas involved in memory.

The key word is regional. This was a specific imaging finding—not evidence that the entire brain became more responsive to insulin or that insulin sensitivity improved throughout the body.

Still, it offers a useful clue: a dietary change appeared to influence a biological process relevant to brain function.

How the memory findings fit

An earlier publication from the same trial reported a 3.6% increase in overall brain blood flow during the peanut period.

Participants also improved on one verbal memory measure, recalling approximately 1.4 additional words after a delay. Researchers did not find improvements in executive function or psychomotor speed.

The newer findings suggest that brain insulin signaling could help explain the memory result. But they do not establish that one caused the other—and these are two reports from the same trial, not independent confirmation.

A whole food, not a proven mechanism

Peanuts provide unsaturated fats, fiber, plant protein, and bioactive compounds. Several components could plausibly contribute to the findings, but the trial cannot identify which mattered most.

It also cannot establish whether peanut butter, other nuts, or a different food substitution would offer similar benefits. The comparison was peanuts versus no peanuts, not peanuts versus a nutritionally matched alternative.

Other limitations matter, too: 31 participants and 16 weeks cannot reveal whether the effects persist or improve everyday functioning. The research was funded by The Peanut Institute Foundation, making independent replication especially valuable.

Make it practical

The study does not mean everyone needs 60 grams of peanuts daily. That was the amount tested—approximately two servings—not a proven optimal dose.

For people who can safely eat peanuts, the practical opportunity is substitution rather than simply adding more food:

• Replace a usual packaged snack with plain, unsalted peanuts.

• Add them to oats, yogurt, or a grain bowl.

• Use them to bring crunch to vegetables or a stir-fry.

Skin-roasted peanuts most closely match the intervention, but the study did not establish that the skins themselves drove the effects.

The takeaway

This trial offers a promising signal that daily peanut consumption may influence how memory-related brain regions respond to insulin.

The next question is whether that response is reproducible—and whether it translates into meaningful, lasting benefits beyond an imaging measurement or a single memory task.

References:

Kerkhof L, Mensink RP, Plat J, Nijssen KMR, Joris PJ. Daily consumption of unsalted, skin-roasted peanuts beneficially affects regional brain insulin responsiveness in older adults: results of a longer-term randomized controlled trial. Food & Function. 2026;17(20):9354–9364. doi:10.1039/D6FO03208G.

Kerkhof L, Mensink RP, Plat J, Nijssen KMR, Joris PJ. Longer-term skin-roasted peanut consumption improves brain vascular function and memory: A randomized, single-blind, controlled crossover trial in healthy older adults. Clinical Nutrition. 2025;55:170–179. doi:10.1016/j.clnu.2025.10.020.