There is a reason why walnuts are shaped like our brains. A recent study found that eating walnuts for breakfast improved performance on cognitive tasks. However, the benefits only appeared six hours later, according to Study Finds. So, eating a handful of walnuts in the morning can improve your mental acuity later in the day.

For the study, participants ate a breakfast of 50 grams of crushed walnuts (about 25 walnut halves), yogurt and muesli one morning. On a different day, they consumed a breakfast with the same amount of calories but instead of walnuts, they had butter on their yogurt and cereal.

At two-, four-, and six-hour intervals after eating breakfast participants were tested on memory recall, mental skills, and mood. Brain acidity was also assessed, and blood tests were conducted. For the mental function tests that involved focusing and decision making, the group that ate walnuts outperformed the group that ate the control breakfast. But, in word-learning tests and memory recall, the walnut group performed worse two hours after eating compared to the control group. This pattern was reversed at the six-hour mark when those who ate the walnuts showed much better memory recall.

According to Women's Health, the researchers found that people performed better overall in a variety of brain function metrics up to six hours after they ate a breakfast that included walnuts. “This study helps strengthen the case for walnuts as brain food,” study co-author Claire Williams. a neuroscientist at the University of Reading, said in a statement. “A handful of walnuts with breakfast could give young adults a mental edge when they need to perform at the top of their game.”

Researchers found that people had faster reaction times on tasks that require planning and multitasking, called executive function tasks, after they ate walnuts. “We also recorded faster response times on attention-related tasks, which were evident at all time points across the day,” says Adrian Whyte, study co-author and lecturer at University of Winchester.

The brain scans showed stronger activity in the areas of the brain responsible for attention and memory in those who ate walnuts. Blood tests revealed that this group also had higher glucose levels which the researchers said benefits brain function.

The downside of the study is that those who ate walnuts expressed more negative feelings, possibly because they didn’t care for the taste of the breakfast. But overall, the brain-boosting benefits of walnuts confirmed previous studies that showed the omega-3 fatty acids, protein compounds, and plant compounds found in walnuts support cognitive health.

The study was conducted by scientists at the University of Reading and commission by the California Walnut Commission and published in the journal Food & Function.