A recent medical study in Spain looked at how eating peanuts affects the brain in older adults. The researchers studied 31 healthy people aged 60 to 75. Each person ate a small amount of unsalted, roasted peanuts every day for 16 weeks, and for another 16 weeks, they did not eat any peanuts. The scientists measured changes in the brain by giving insulin through the nose and using a special scan called magnetic resonance imaging, which takes pictures of the brain.

The most important reason for this study was to see if peanuts could change how insulin works in the brain, especially in areas important for memory. Insulin is a hormone that usually helps control sugar levels in the body, but it may also help the brain work better and support memory functions.

After eating peanuts, the study found a different reaction in part of the brain related to memory and visual information. This suggests peanuts could help the brain respond better to insulin. However, the study was small and does not prove that peanuts prevent memory loss or help with diseases like dementia. More research is needed to be sure.