NCT06430086 Mechanistic Effect of Walnut Consumption on Sleep Quality

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This trial targets 24 participants in total. It began in 2024-06-28 with a primary completion date of 2026-12-31.

Brief Summary

Poor sleep quality is very common in modern society. Walnuts contain many nutrients that may be helpful for sleep, including melatonin and polyphenols. Some studies show that eating foods high in melatonin and polyphenols improves sleep quality, but walnuts have not been studied specifically. This study proposes to test if eating walnuts improves sleep compared to a food that lacks these sleep-promoting factors. The investigators expect that walnut consumption for 4 days will increase melatonin levels and lead to better sleep quality compared to a high-carbohydrate, high-sugar food. The study will enroll middle-aged and older adults with sleep complaints to participate in this study. Each person will eat the two different foods for 4 days each in random order. The 4-day periods will be separated by at least 2-3 weeks. Sleep quality will be measured by questionnaire and with a wrist monitor every day. The investigators will also do a sleep study using electroencephalography (EEG) on night 3 and take measures of circadian physiology (natural body rhythms) in the laboratory on day 4 (including overnight) by measuring body temperature and blood and urine melatonin. The study findings may provide new options to improve sleep health from increased walnut consumption.

Eligibility Criteria

Inclusion Criteria: * Equal numbers of men and women (12 male and 12 post-menopausal female) * Equal number of individuals with normal weight (18.5-24.9 kg/m2) and overweight (25-29.9 kg/m2) * Participants will self-report poor sleep quality, reflected by a global score \>5 on Pittsburgh Sleep Quality Index Exclusion Criteria: * Diagnosed sleep disorder * Participants with conditions that could affect sleep will be excluded: * smoking, excessive caffeine intake (\>300 mg/day) * shift work * chronic pain * diagnosis of a chronic disease (e.g., uncontrolled hypertension, pre-diabetes, type 2 diabetes, chronic kidney disease, chronic obstructive pulmonary disease), * autoimmune diseases * cardiovascular event or cancer in the past 24 months * psychiatric/neurologic disease or disorder, or sleep disorder (diagnosed or high risk for sleep apnea, chronic insomnia, restless leg syndrome, narcolepsy) * use of medications that influence CYP1A2 enzymes * Allergy/intolerance to nuts, tree nuts, or unwilling to eat study foods

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