WEB DESK
— A new randomized controlled trial has found that eating a daily serving of walnuts with dinner may help young adults fall asleep faster, sleep more soundly, and feel less drowsy during the day. The study, published in Food & Function by researchers at the University of Barcelona, is among the first to demonstrate walnuts’ potential as a natural, food-based aid for better sleep.
The eight-week study involved 76 healthy participants aged 20–28, who consumed about 40 grams of walnuts daily during one phase and no nuts during another. Results showed that walnut consumption increased evening levels of 6-sulfatoxymelatonin (6-SMT), a marker of the sleep hormone melatonin, by a significant margin. Participants also reported improved overall sleep quality, took less time to fall asleep (1.3 minutes faster), and experienced less daytime sleepiness compared to the nut-free period.
Lead researcher Dr. Maria Izquierdo-Pulido said this is the first trial to show that daily walnut consumption can objectively improve sleep quality while boosting melatonin levels. “Insufficient sleep is a global public health challenge linked to chronic illness, cognitive decline, and economic costs. Simple dietary changes could be part of the solution,” she explained.
Walnuts contain several nutrients linked to sleep regulation, including tryptophan, melatonin, magnesium, and B vitamins. According to co-leader Dr. María Fernanda Zeron-Rugerio, the timing of walnut intake was less important than consistency. “Daily intake, not just eating them at dinner, likely drove the benefits,” she noted.
While the researchers highlighted certain limitations — such as not measuring participants’ overall tryptophan and melatonin intake — they believe the findings add to a growing body of evidence showing diet’s critical role in sleep health. More studies are needed to confirm the long-term impact, but the results suggest that adding walnuts to daily meals may be a simple step toward better rest.
The study was funded by the California Walnut Commission, though the group did not influence its design, results, or publication.