A simple daily snack of unsalted, skin-roasted peanuts could be a powerful tool for supporting brain health in later life, according to a new scientific study. Researchers have discovered that older adults who consumed a modest portion each day experienced significant improvements in memory and increased blood flow to the brain.
The Study: A Peanut-Powered Brain Boost
The research, conducted by scientists at Maastricht University in the Netherlands, involved 31 healthy adults aged between 65 and 75. None of the participants had a history of cardiovascular disease, diabetes, or peanut allergies, and they were all non-smokers. The study used a crossover design, meaning each person acted as their own control.
For 16 weeks, participants ate 60 grams (roughly two handfuls) of unsalted, skin-roasted peanuts daily. This was followed by an eight-week break, and then a 16-week control period where they avoided peanuts and other nut products entirely. This method allowed for a direct comparison of the effects of peanut consumption.
Measurable Improvements in Memory and Blood Flow
The results were clear. During the peanut-eating phase, participants showed a 5.8 percent improvement in verbal memory. They performed notably better at recalling words from a list they had seen 20 minutes earlier.
Perhaps more crucially, advanced brain imaging revealed a marked increase in cerebral blood flow. Global blood flow to the brain rose by 3.6 percent, while flow to the brain's grey matter increased by 4.5 percent. The benefits were even more pronounced in key regions: blood flow jumped by 6.6 percent in the frontal lobes and 4.9 percent in the temporal lobes, areas heavily involved in memory and language processing.
Why Do Peanuts Have This Effect?
Lead researcher Peter J Joris explained the significance: 'Adequate blood flow in the brain is important for the delivery of oxygen and nutrients to the brain cells. Without enough oxygen and nutrients, the highly metabolically active brain cannot function properly, and key functions like memory can be affected.'
The study suggests two primary components in peanuts are responsible for the boost. Firstly, they contain L-arginine, an amino acid known to help increase blood flow. Secondly, the bioactive compounds and antioxidants present in the peanut skins are thought to help protect brain cells. 'The skin contains many antioxidants and fibre that may contribute to the beneficial effects,' Joris noted.
Interestingly, despite adding roughly 340 extra calories per day from the peanuts, participants' body weights remained largely stable, likely because they subconsciously adjusted their intake of other foods.
Conclusions and Considerations for Brain Health
'Our results suggest that eating unsalted, skin-roasted peanuts every day can support brain health as we age,' Joris concluded. The researchers were particularly intrigued that the improvements were observed across the whole brain, indicating a widespread effect on vascular function.
The study does have some limitations, primarily that participants knew when they were eating the peanuts, which could influence behaviour. However, the team analysing the brain scans and memory tests were unaware of which phase each participant was in, strengthening the findings.
While the exact mechanism—whether it's the L-arginine, the skins, the healthy fats, or a combination—is not yet fully understood, the link between daily peanut consumption and better brain function is compelling. It offers a promising, accessible dietary strategy for maintaining cognitive vitality in older age.
