Eating 50 grams of walnuts mixed into muesli and yoghurt led to faster reaction times throughout the day and better memory performance later in the day when compared to eating an equivalent calorie-matched breakfast without nuts, according to a team of scientists from the University of Reading, the University of Winchester, and USDA Human Nutrition Research Center on Aging at Tufts University.
Eating walnuts for breakfast could improve brain function for healthy young adults. Image credit: Tim Ulama.
“Diet represents one of the most important lifestyle factors that can strongly influence cognitive functioning,” said University of Reading’s Professor Claire Williams and colleagues.
“Thus, a well-balanced diet, rich in nutrients, can improve cognitive function throughout life.”
“One class of foods that has been linked with beneficial cognitive wellbeing is the nut family, with several epidemiological studies highlighting a positive relationship between regular nut consumption and cognitive function.”
“For example, epidemiology studies such as the Doetinchem Cohort Study found that levels of nut consumption positively predicted memory, processing speed, cognitive flexibility, and global cognitive function in middle-aged adults, while data from the Nurses’ Health Study showed that older women consuming five or more servings of nuts per week had better cognitive function than non-consumers, along with an indication that walnuts positively contributed to this effect.”
“Pre-clinical studies have also demonstrated the cognitive benefits of walnut supplementation.”
“Studies in rodents have found that walnuts facilitated improved working memory performance in the Morris Water Maze task and improved Elevated-Plus and Radial Arm maze learning and memory performance.”
“Cognitive benefits of walnuts may be due to their specific nutrient content as they are known to be high in omega-3 fatty acids, protein/peptides, and flavonoids, a class of polyphenols,” they added.
“The main objective of our study was to determine the cognitive and mood effects of acute consumption of a walnut-rich breakfast in healthy young adults throughout the day and, secondly, to investigate potential neurological and physiological mechanisms that may explain any cognitive benefits.”
The study involved 32 healthy young adults aged 18-30 who consumed both a walnut-rich breakfast and a matched breakfast on separate occasions.
The participants completed various cognitive tests while their brain activity was monitored in the six hours after eating each breakfast.
“A handful of walnuts with breakfast could give young adults a mental edge when they need to perform at the top of their game,” Professor Williams said.
“It’s particularly exciting that such a simple dietary addition could make a measurable difference to cognitive performance.”
Brain activity recordings revealed changes in neural activity that suggest walnuts may help the brain work more efficiently during challenging mental tasks, while blood samples revealed positive changes in glucose and fatty acid levels — both factors that could influence brain function.
“Our findings provide evidence for reaction time benefits throughout the day following a walnut-rich breakfast, while memory findings were mixed with benefits only observed later in the day,” the researchers said.
“However, more research is needed into how diets containing walnuts might regulate cognitive improvements in humans postprandially and over the longer term.”
The results were published in the journal Food & Function.
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L. Bell et al. The impact of a walnut-rich breakfast on cognitive performance and brain activity throughout the day in healthy young adults: a crossover intervention trial. Food Funct, published online February 3, 2025; doi: 10.1039/D4FO04832F
