Using electroencephalograms (EEG), the team was able to measure the brainwaves produced from nut consumption by the participants. The researchers recorded EEG wave bands from nine regions of the scalp -- areas that are correlated with cerebral cortical function.
According to their research, those who regularly consumed pistachios produced the most gramma wave responses. The team noted that the gramma waves produced from pistachios are those connected with cognitive processing, information retention, learning, perception and rapid eye movement during sleep.
Meanwhile, the team recorded the most delta responses from those who were peanut-eaters. The responses related to eating peanuts were associated with immunity, natural healing and deep sleep. Peanuts were included in the study despite them being legumes.
"This study provides significant beneficial findings by demonstrating that nuts are as good for your brain as they are for the rest of your body," said Lee Berk, the study’s principal author and associate dean for research at the university’s School of Allied Health Professions.
Berk added that while each nut varied in terms of the amount and type of brainwave it produced, all of the nuts in their study have high antioxidant content, which is vital for preventing oxidative stress linked to the development of chronic diseases. The researchers also said that the antioxidants in nuts have cardioprotective, anticarcinogenic and anti-inflammatory properties. (Related: Nuts are brain food: Study reveals consuming nuts during pregnancy may help improve brain development in children.)
In their report, the researchers explained that they focused on the effects of nuts on brain function because while these foods are good sources of flavonoids, there is still not enough information about the effects of nut flavonoids on neurocognition, neuronal synchronization, memory, recall, mood and behavior. But what was known to the team prior to the study was that flavonoids from food sources such as nuts penetrate and accumulate in the brain, especially in the hippocampal regions where learning and memory take place.
Not only do nuts enhance brain function, but they also show potential in promoting mental health.
In one study, walnut consumption was linked to reduced depression. Over 26,000 people submitted information about their dietary patterns, specially their consumption of walnuts. The researchers recorded the participants' depression scores based on a questionnaire they answered.
The researchers analyzed the data and found that those who were regular walnut consumers had lower depression scores than those who didn't eat walnuts. Moreover, the walnut consumers reported having greater interest in doing things, feeling less hopelessness, being more energetic and having better concentration and greater optimism.
Based on these findings, the researchers concluded that eating nuts is beneficial to mental health. But they stressed that walnuts, in particular, has the highest efficacy in reducing depression symptoms.
"In conclusion, a consistent association was observed between the consumption of nuts, and walnuts in particular, with fewer and less frequent depressive symptoms in a representative sample of the U.S. population over the course of the past decade. This association was consistent across both genders but consistently stronger among women than men. Lower depression scores among consumers of walnuts appear to be traced back to better concentration, higher energy levels, more interest in doing things, and greater self-control of rates of speech and movement," the researchers wrote in their report.
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