Walnut Consumption Improves Sleep Quality: A Randomized-Controlled Trial

Izquierdo-Pulido M, Zerón-Rugerio MF, Ibarra-Picón A, Diez-Hernández M, Pérez-Cano F, Cambras T · The 14th European Nutrition Conference FENS 2023 · 2024 February 28

DOI 10.3390/proceedings2023091381

Objective

To investigate if daily consumption of walnuts could have a positive impact on sleep quality in young adults.

Conclusions

The 8-week intervention with walnuts was significantly associated with improved sleep quality, lower sleep latency, higher sleep efficiency, and reduced daytime sleepiness. The intervention also led to an increase in the concentration of melatonin in urine samples.

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Insights

Daily consumption of walnuts improves sleep quality and reduces daytime sleepiness in healthy young adults.

In the above-mentioned experimental trial, 80 young adults were randomly selected to either consume 40 grams of walnuts daily or abstain from eating walnuts and any other nuts for 8 weeks, followed by a two-week break. Actigraphy was used to measure sleep quality, from various dimensions such as duration, latency, awakenings, and sleep efficiency, while daytime sleepiness was measured using the Epworth Sleepiness Scale. Furthermore, the concentration of 6-sulfatoxymelatonin, a melatonin metabolite, was assessed in urine samples collected at two intervals throughout the day and night. This research observed a notable improvement in the subjects' sleep quality after an 8-week period of walnut consumption. The participants experienced shorter sleep latency, greater sleep efficiency, and reduced daytime sleepiness. Additionally, there was a heightened concentration of 6-sulfatoxymelatonin in urine samples collected between 20:00 to 23:00. These results suggest that a daily intake of 40 grams of walnuts may augment the secretion of melatonin, thereby improving sleep quality and reducing daytime sleepiness in healthy young adults.