What eating peanuts every day could do to your brain, according to researchers

A bowl of peanuts on the table usually means salt and a drink. But researchers at Maastricht University Medical Center looked at a rather different kind of snack: unsalted peanuts, roasted in their skins, eaten every day. They asked 31 healthy people aged 60 to 75 to make them part of their daily routine for 16 weeks, then compared the results with a period when they ate no peanuts.

It wasn't simply a question of whether the participants felt sharper or remembered more. The researchers used MRI scans to look at what was happening inside the brain, and a second study has now examined another possible piece of the puzzle. So what did they find, and does it mean you should be adding peanuts to your shopping list?

What did the Maastricht researchers do?

The team at Maastricht University's NUTRIM institute conducted a randomised, single-blind crossover trial involving 31 healthy older adults, with an average age of 67. Each participant followed two 16-week periods: one in which they ate 60 grams of unsalted, skin-roasted peanuts every day, and another in which they ate no peanuts. An eight-week break separated the two periods.

The researchers used MRI scans to measure cerebral blood flow, meaning how much blood circulates through the brain. They also assessed participants' cognitive performance using a series of tests. The findings were published in Clinical Nutrition in November 2025. 

What happened to blood flow and memory?

During the peanut-eating period, overall blood flow to the brain was 3.6% higher than during the period without peanuts. Blood flow in grey matter increased by 4.5%.

The researchers also recorded a 5.8% improvement in one part of a verbal memory test. Participants were better at recalling words after a delay. Systolic blood pressure fell by an average of 5 mmHg during the peanut period, too.

However, not every cognitive measure improved. The researchers found no significant benefits in tests of executive function or psychomotor speed. In other words, the results point to changes in certain measurements, not a general improvement in every aspect of memory or thinking. The published study provides the full results.

A follow-up study looked at insulin in the brain

In October 2026, the team published a second paper in Food & Function. This time, they examined whether eating peanuts could influence how memory-related areas of the brain respond to insulin.

Insulin is best known for helping regulate blood sugar, but it also has a role in brain function. To investigate this, researchers administered insulin through the nose and used MRI scans to measure changes in blood flow in response.

They identified a change in insulin responsiveness in a region of the right side of the brain that included areas associated with memory, such as the hippocampus. The authors described the result as potentially beneficial, and suggested it could help explain the earlier findings. However, it does not show that peanuts prevent dementia or reverse age-related memory decline.

Which peanuts should you buy, and how many?

One detail worth paying attention to is the type of peanut. The participants ate unsalted peanuts roasted in their skins, without a salty, sugary or flavoured coating. That's the specific version used in the trial.

The amount, however, was 60 grams a day. That's twice the 30-gram daily portion recommended for adults by the Dutch Voedingscentrum. Its advice includes peanuts as part of the nut category and recommends choosing unsalted varieties.

The study portion is also a substantial snack: 60 grams provided around 340 calories. So the research dose shouldn't be mistaken for a new dietary recommendation. A handful of unsalted peanuts is a more practical way to follow the existing advice. Anyone with a peanut allergy should avoid them.

What the findings don't tell us

There are important limitations. The trials involved only 31 people, all of whom were healthy older adults. The intervention lasted 16 weeks, so the researchers cannot say whether the effects would continue over years or apply to people with existing cognitive conditions.

There's also a funding detail worth knowing: the research received support from The Peanut Institute Foundation. The researchers stated that the foundation did not take part in the study design, data collection or analysis, or the decision to publish. Still, it's relevant context when interpreting the findings.

For now, the studies offer an interesting reason to look more closely at an everyday snack. They don't establish peanuts as a treatment for memory problems or a way to prevent dementia.