Walnuts With Breakfast Make Your Brain Work Better – But There’s A Surprising Catch

READING, England — Grabbing a handful of walnuts with breakfast might sharpen your thinking, research shows, but don’t expect an immediate memory boost. That’s because there’s a surprising pattern to the cognitive benefits of these nutrient-packed nuts.

The study, conducted by scientists at the University of Reading and commissioned by the California Walnut Commission, discovered that eating walnuts in the morning led to faster reaction times on complex thinking tasks throughout the day. Memory benefits, however, only appeared six hours after consumption—long after most people would expect nutritional effects to kick in.

The Walnut Experiment

Thirty-two young adults (ages 18-30) participated in this controlled experiment, visiting the lab twice. On one visit, they ate breakfast with 50 grams of crushed walnuts mixed into muesli and yogurt. On another visit, they had an almost identical breakfast where butter replaced the walnuts. Both meals contained the same calories, though the walnut breakfast uniquely provided omega-3 fatty acids and plant compounds called polyphenols.

After breakfast, participants completed cognitive tests at baseline and again at 2, 4, and 6 hours later. These tests measured memory recall, executive function (mental skills for planning and self-control), and mood. Researchers also recorded brain activity and collected blood samples.

Quick Thinking vs. Better Memory

On tasks measuring executive function—mental abilities like focusing, decision-making, and controlling impulses—people consistently responded faster after eating walnuts compared to the control breakfast.

The memory results revealed an unexpected pattern. In word-learning tests, participants actually performed worse two hours after eating walnuts compared to the control breakfast. By the six-hour mark, however, this completely reversed—walnut eaters suddenly showed better recall than the control group.

Brain scans provided additional clues about these effects. EEG readings showed different brainwave patterns between conditions, particularly in regions linked to attention and memory. Those who ate walnuts showed stronger activity in specific brainwave bands, hinting at different levels of mental engagement during tasks.

Blood tests revealed another clue: higher glucose levels but lower fatty acids after walnut consumption. The researchers explained in their Food & Function paper that “small increases in availability may have an impact on the delivery and uptake of glucose to the brain during periods of high cognitive demand, thereby benefitting postprandial cognitive performance.”

The Downside and Practical Takeaways

Not everything about the walnuts was positive. Participants reported feeling more negative emotions after the walnut breakfast—likely because they simply didn’t enjoy eating it. They rated the walnut breakfast as smelling worse than the control meal.

Previous studies have established that regular nut consumption correlates with better cognitive health. The Nurses’ Health Study showed older women eating five or more servings of nuts weekly performed better on cognitive tests than non-consumers.

Scientists believe walnuts’ brain benefits stem from their unique nutritional profile—they contain omega-3 fatty acids, protein compounds, and beneficial plant chemicals that support brain function through different mechanisms.

The key takeaway? If you’re considering walnuts for brain health, don’t expect immediate benefits for all mental skills. Their effects on memory take time to develop, while improvements in reaction speed and executive function appear more consistently throughout the day.

For anyone with mentally demanding tasks scheduled later in the day, a morning handful of walnuts might provide a valuable edge—just be prepared for potentially mixed results if you need peak mental performance right after breakfast.