Effects of Daily Avocado Consumption on Sleep and Skin Health in Postmenopausal Females

Poor sleep quality and accelerated skin aging are common in postmenopausal women and may be linked, in part, through impaired vascular function. Avocados contain monounsaturated fats, carotenoids, vitamin E, magnesium, fiber, and other bioactive compounds that may support vascular health and, in turn, improve sleep and skin health. This randomized controlled trial will evaluate whether consuming one medium Hass avocado daily for 8 weeks improves sleep quality and skin health compared with a calorie- and fatty-acid-matched safflower oil control in postmenopausal women with poor sleep quality and overweight or obesity. The study will enroll 74 postmenopausal women aged 50-65 years who have poor habitual sleep quality. Participants will be randomly assigned to consume either one medium Hass avocado per day or 27 g of safflower oil per day for 8 weeks. Sleep will be assessed using wrist actigraphy, at-home electroencephalography, sleep diaries, and validated sleep questionnaires. Skin hydration, elasticity, barrier function, collagen, pigmentation, and wrinkles will also be assessed. Vascular function will be measured using flow-mediated dilation and blood biomarkers. The investigators expect that daily avocado consumption will improve sleep quality, skin health, and vascular function compared with the control condition and will explore whether improvements in vascular function contribute to improvements in sleep and skin health.

Inclusion Criteria: * Postmenopausal women aged 50-65 years * Individuals with overweight or obesity, defined as BMI 25-35 kg/m² * Postmenopausal, defined as no menstrual period for at least 12 months * Participants with poor habitual sleep quality, reflected by a global score \>5 on the Pittsburgh Sleep Quality Index (PSQI) * Participants with Fitzpatrick skin types II-IV * Participants willing to maintain their usual skin-care routine throughout the study, avoid excessive sun exposure, and not initiate new skin treatments Exclusion Criteria: * Current smokers * Individuals with caffeine intake \>300 mg/day * Excessive alcohol or drug use * Individuals engaged in shift work * Current use of hormone replacement therapy * Individuals with chronic pain or major chronic disease/medication likely to affect study outcomes, including uncontrolled hypertension, prediabetes/type 2 diabetes, chronic kidney disease, COPD, autoimmune disease, recent cardiovascular event, or cancer within the past 24 months * Psychiatric or neurologic disease/disorder likely to affect sleep * Individuals with a diagnosed sleep disorder or high risk for sleep apnea, defined as a STOP-Bang score ≥3 * Individuals using medications to regulate sleep * Individuals planning time-zone travel during the study * Pregnancy or lactation * Allergy or intolerance to study foods * Individuals who dislike avocado and/or safflower oil, defined as a taste pleasantness rating \2 avocados per month