Adding one simple thing to your breakfast every morning could make you brainier according to a new study.

Researchers at the University of Reading found that eating a generous handful of walnuts led to faster reaction times throughout the day - and better memory performance later in the day.

The study, published in Food & Function, saw young adults aged 18 to 30 consume 50g of walnuts and muesli in yoghurt or an equivalent calorie-matched breakfast without nuts.

In the six hours after eating each breakfast, participants completed various cognitive tests, and their brain activity was monitored.

Professor Claire Williams, who led the research from the University of Reading, said: “This study helps strengthen the case for walnuts as brain food.

Blood samples revealed positive changes in glucose and fatty acid levels - both factors that could influence brain function.

"A handful of walnuts with breakfast could give young adults a mental edge when they need to perform at the top of their game. It's particularly exciting that such a simple dietary addition could make a measurable difference to cognitive performance."

The findings build on previous research showing the cognitive impacts of regular nut consumption, including walnuts.

This is the first study to examine the immediate effects of walnuts on brain function in young adults over the course of a single day.

Brain activity recordings revealed changes in neural activity that suggest walnuts may help the brain work more efficiently during challenging mental tasks.

The researchers suggest that walnuts' mix of nutrients - including omega-3 alpha-linolenic fatty acids, protein, and plant compounds called polyphenols - may enhance cognitive performance.

However, they note that more research is needed to fully understand how walnuts produce these beneficial effects on the brain.

Breakfast is the most important meal of the day, according to many experts.

Dan Buettner, an American author and longevity researcher, has established Blue Zones around the world after examining what people eat in different countries and how it contributes to reaching incredible ages—often over 100.

After examining people from Okinawa in Japan, Sardinia in Italy, Nicoya in Costa Rica, Ikaria in Greece and Loma Linda in California, he has shared the 'best' foods for longevity that you can combine into your morning meal.