Location: Nutrition, Food Safety/Quality
Project Number: 0500-00117-001-008-A
Project Type: Cooperative Agreement
Start Date: Aug 1, 2026
End Date: Oct 31, 2028
Objective:
The Cooperator will conduct an 8-week randomized, controlled, single-blinded, parallel-arm clinical trial to evaluate the effects of daily peanut consumption on brain health, mental wellness, and sleep quality in healthy adults self-identifying as regularly feeling stressed. One hundred participants (ages 18–40, 50% female and 50% male assigned at birth) who self-identify as regularly experiencing stress will be recruited and randomly assigned to consume either 56 g/day of skin-roasted peanuts or 56 g/day of plain unsalted hard pretzels for 8 weeks.
The specific objectives of this project are as follows:
Brain Activity & Cognition: To determine whether daily peanut consumption alters prefrontal cortical recruitment and improves performance on tasks measuring attention, executive function, and working memory compared to control.
Sleep Architecture & Autonomic Nervous System Function: To determine whether daily peanut consumption improves sleep architecture, fatigue, increases resting heart rate variability (HRV), and improves salivary melatonin levels compared to control.
Mental Wellness & Perceived Stress: To determine whether daily peanut consumption reduces self-reported perceived stress, anxiety, and negative affect, and attenuates salivary cortisol and alpha-amylase responses to a standardized mild cognitive stressor compared to control.
Findings will be disseminated through two peer-reviewed publications and a presentation at a national scientific conference such as the American Society for Nutrition Annual Meeting.
Approach:
One hundred young adults (ages 18–40, 50% female and 50% male assigned at birth) who self-identify as regularly experiencing stress will be recruited through recruitment posters, word of mouth, and social media. Participants will be randomly assigned 1:1 to consume either 56 g/day of skin-roasted peanuts or 56 g/day of plain unsalted hard pretzels for 8 weeks. Participants will be instructed to replace their typical daily snack with the assigned intervention food and to otherwise maintain their usual diet while refraining from consuming additional nuts or nut butters. Dietary adherence will be monitored via weekly 3-day food records, text and email check-ins, leftover item counts, and self-reported missed days. Participants will be instructed to consume the intervention food earlier in the day with a meal. Recipes to optimize carbohydrate and potassium intake will be provided weekly to participants to enhance tryptophan transport across the blood brain barrier.
To address Aim 1, prefrontal cortical activity will be assessed at baseline and week 8 using high-density wireless functional near-infrared spectroscopy (fNIRS) during validated cognitive tasks measuring spatial recall, digit span, word association, trail making, and matrix reasoning. Changes in oxygenated hemoglobin in the prefrontal cortex will serve as the primary neuroimaging outcome.
To address Aim 2, participants will wear validated wearable biosensors continuously throughout the 8-week intervention to capture dozens of variables such as: physical activity, total sleep time, sleep efficiency, sleep onset latency, and heart rate variability (HRV) on a 24-hour basis. Salivary melatonin will be collected at baseline and week 8. The Pittsburgh Sleep Quality Index (PSQI) and Chalder Fatigue Scale will be administered at baseline, week 4, and week 8 to supplement objective biosensor data.
To address Aim 3, the Depression Anxiety Stress Scales (DASS-21), Perceived Stress Questionnaire (PSQ), and Positive and Negative Affect Schedule (PANAS) will be administered at baseline, week 4, and week 8. Salivary cortisol and alpha-amylase will be collected at baseline and week 8 in response to a validated laboratory cognitive stress paradigm, with samples collected at multiple time points to characterize reactivity and recovery. Ecological momentary assessments (EMAs) will be administered throughout the intervention via a smartphone application to capture real-time mood and energy levels. All salivary assays will be conducted using commercially available enzyme-linked immunosorbent assay (ELISA) kits.
The primary statistical approach will be mixed-model repeated-measures analysis of variance (ANOVA) comparing outcomes between groups across time points. Covariates will include but not limited to: adherence, age, biological sex, body mass index (BMI), physical activity, mood disorder diagnoses, alcohol, nicotine, and cannabis sativa use. Both intention-to-treat and per-protocol analyses will be performed using SAS v9.3, conducted in a blinded manner.