Unlike the encouraging findings in the 2025 study, researchers did not identify significant differences between the groups in cognitive performance or brain activation during memory tasks.
This is an important distinction. The results do not prove that peanuts are ineffective, but they show that benefits observed in one group of healthy older adults cannot automatically be expected in people who already have memory complaints or cardiovascular risk factors.
The studies were also relatively small and used different participant groups, study designs, and peanut interventions. Larger and longer trials are needed to understand who might benefit and whether the effects last.
A Follow-Up Study Explores Brain Insulin Responsiveness
In 2026, the Maastricht research group published a further analysis involving the same 31 older adults who participated in the longer-term peanut trial.
Researchers examined how the brain responded to insulin delivered through the nose. They identified a change in insulin-related blood-flow responses in a brain region that included areas associated with memory.
This finding may help researchers investigate possible biological mechanisms behind the earlier results. However, it is an exploratory finding—not proof that peanuts improve memory by directly treating brain insulin resistance.
It also does not establish that peanuts prevent Alzheimer’s disease or reverse cognitive decline.
How Many Peanuts Should You Eat?
The 2025 study used 60 grams of unsalted, skin-roasted peanuts daily. That is approximately two small handfuls, although the exact amount depends on the size of the peanuts and your handful.
This was the research dose, not a universal medical recommendation.
Peanuts are nutritious but calorie-dense. Sixty grams can provide roughly 340 calories, depending on the product and preparation. For people watching their weight, peanuts are best used to replace less nutritious snacks rather than simply adding extra calories to the usual diet.
