Previous studies have already shown that introducing more nuts into the Mediterranean diet can protect against cognitive decline associated with aging and help preserve memory. But how do nuts actually affect brain activity? A team of researchers from Loma Linda University in Beaumont, California (USA) set out to find out.
Led by the expert Lee Berk, the scientists started from the observation that nuts have high concentrations of flavonoids, that is, antioxidants that are believed to have anti-inflammatory, anti-carcinogenic and heart-protective effects. In the same way, flavonoids also access areas of the hippocampus of the brain that are responsible for learning and memory.
Scientists believe that these flavonoids induce neuroprotective effects, leading to the “neurogenesis” or “birth” of new neurons, in addition to improving blood flow to the brain.
But how would these benefits translate into electrical activity in the brain? To find an answer, they asked the study participants to regularly consume nuts to allow an electroencephalogram (EEG) to measure their brain activity. In particular, the volunteers took almonds, peanuts, pecans, pistachios, cashews and nuts regularly.
Nuts induce strong gamma and delta waves
The brain waves were measured while experiencing a “sequence of improvement of sensory awareness tasks ranging from the cognition of past experience, visualization, smell, taste and finally the consumption of nuts,” the authors comment.
These sequences were varied so that the EEG could measure brain activity in nine different cortical regions.
“This study provides objective evidence that [the strength of the brain wave] for different EEG brain wave bands is modulated differently according to different types of nuts.” These data seem to support an association of benefits for the health of the fruits. Dry with an increase in [delta waves] and [gamma waves], “they explain.
In particular, peanuts resulted in a stronger delta wave response (associated with a healthy immune response and non-REM deep sleep); while pistachios produced the highest response in gamma waves (associated with perception, sleep with rapid eye movement (REM) and the processing and retention of information, and are generally thought to improve cognitive processing). The delta and gamma waves were higher with the pecans.
The researchers also analyzed the antioxidant concentration of each type of nut and discovered that the nuts had the highest levels of this substance, followed by pecan nuts and cashew nuts.
In general, all six varieties of nuts had high levels of beneficial antioxidants.
“This study provides significant beneficial insights by showing that nuts are as good for your brain as they are for the rest of your body,” says Lee Berk.
The authors hope that the following studies will reveal new benefits of nuts for both the brain and the nervous system.