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NCT Number: NCT07735221

Impact of Peanut Consumption on Stress, Immune Function, Inflammation, and Cardiovascular Health in High-Stress Individuals

The purpose of this research is to determine whether peanut consumption improves indicators of cardiovascular disease (CVD) risk in human subjects following the consumption of study foods.

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Key information

Conditions

Immune System Cardiovascular Health Chronic Stress Inflammation Pathologic Processes Pathological Conditions, Signs and Symptoms Stress

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Western Human Nutrition Research Center

Davis, California, 95616, United States

Location contact

Danielle Lemay, PhD

SUB_INVESTIGATOR

Ellen Bonnel, PhD

CONTACT

[email protected]

530-752-4184

Ione Summers, B.S.

CONTACT

[email protected]

530-754-8544

Kevin Laugero, PhD

SUB_INVESTIGATOR

Mary Kable, PhD

SUB_INVESTIGATOR

Ryan Snodgrass, PhD

PRINCIPAL_INVESTIGATOR

About this study

The overall goal of the proposed study is to determine whether peanut consumption improves indices of cardiovascular disease (CVD) risk in human subjects with high levels of perceived chronic stress. Chronic stress is a growing public health concern and is associated with adverse health outcomes, including CVD. Stress, experienced when a person feels that environmental, physiological, or psychosocial demands tax or exceed their adaptive capacity, triggers a coordinated response from the sympathetic nervous system (SNS) and hypothalamic- pituitary- adrenal (HPA) axis increasing blood pressure, driving systemic inflammation, and affecting the immune system by accelerating the output of disease-promoting immune cells from bone marrow.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • Males and females
  • 18-65 years old
  • BMI ≥ 18.5 kg/m2 and ≤ 39.9 kg/ m2
  • Recruitment will be based on Perceived Stress Scale - 4 (PSS-4) score

Exclusion criteria

  • Less than 18 and over 65 years old
  • Pregnant or lactating women
  • Adults who rely on prescription medication that may influence study variables, apart from birth control
  • BMI < 18.5 kg/m2 and > 39.9 kg/m2
  • Smokers who currently use tobacco- or marijuana-containing products including e-cigarettes, vape pens, pod mods, tanks, and electronic nicotine delivery devices (ENDS)
  • Habitual consumption of nuts, nut butters, nut powders, nut side dishes, nut bars or other nut products
  • Known food allergies (milk, eggs, fish, shellfish, tree nuts, peanuts, wheat, soybeans, sesame, corn) due to samples not prepared in a hypoallergenic environment
  • Currently living in close contact with individuals who have an allergy to peanuts, in order to avoid exposing these individuals to an allergen
  • Self-reported history of difficulties with blood drawing procedures including prior fainting or dizziness, or veins assessed as not suitable for four separate venipunctures by licensed phlebotomist
  • Diagnosed active chronic diseases for which the individual is currently taking daily medication, including but not limited to:
  • Diabetes mellitus, cardiovascular disease, cancer, gastrointestinal disorders, kidney disease, liver disease, bleeding disorders, asthma, autoimmune disorders, hypertension, osteoporosis
  • Recent minor surgery (within 4 weeks) or major surgery (within 16 weeks)
  • Known gallbladder disease or history of cholecystectomy
  • History of gastrointestinal surgery, including gastric bypass surgery or resection
  • Diagnosis of irritable bowel syndrome
  • Recent antibiotic therapy (within 4 weeks)
  • Recent hospitalization (within 4 weeks)
  • Current participation in another research study
  • Has HIV/AIDS, hepatitis, or another disease that affects the immune system
  • Gives regular blood donations and is unwilling to stop during the study
  • Blood Pressure ≥ 140 mmHg systolic or 90 mmHg diastolic
  • Current diagnoses of an eating disorder (ex. anorexia, bulimia, etc.)
  • High - very high triglyceride levels: ≥ 300 mg/dL
  • Adults who are unable to consent, individuals who are not yet adults (infants, children and teenagers), pregnant women and prisoners will be excluded from participation in the study
  • Participants who are unwilling to collect and transport urine, stool and saliva samples
  • Abnormal hemoglobin and/or hematocrit levels
  • Abnormal liver function (defined as liver enzymes that are >200% of upper limit (ALT upper limit is 43 U/L or Aspartate transaminase (AST) upper limit is 54 U/L)
  • Unwillingness to discontinue probiotic, prebiotic, fiber, or other supplements (except RDA-level vitamin and mineral supplements) during the study
  • Unwilling to consume study foods
  • Alcohol consumption > 20 g/day

Treatment and study plan

Peanuts, roasted, salted with skins

Other

42g roasted salted peanuts with skins consumed daily

Isocaloric food

Other

Corn chips (45g)

Primary outcomes

  1. Change in psychosocial stress over time

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    The PSS-10 will be administered 4 times during the study. The 10-item Perceived Stress Scale (PSS-10) is a validated, standard instrument used to assess subjective perceptions of chronic psychological stress (i.e., excessive demands, insufficient coping resources, and a perceived lack of control).

    The minimum score is 0 and the maximum score is 40. Higher scores indicate greater severity of psychosocial stress.

  2. Change from baseline of allostatic load following dietary interventions

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Before and after each intervention, cumulative physiological stress load, also referred to as allostatic load (AL), will be calculated. AL will be derived from 12-h overnight urinary cortisol, norepinephrine, and epinephrine levels (corrected for urinary creatinine levels), resting systolic and diastolic blood pressure, and overnight fasted waist-to-hip ratio, fasting serum levels of high-sensitivity C-reactive protein (hs-CRP), cholesterol, HDL-cholesterol, fasting plasma dehydroepiandrosterone sulfate (DHEA-S), and whole blood glycohemoglobin (HbA1c).

  3. Change from baseline of monocyte gene expression

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Total monocytes isolated from human peripheral blood mononuclear cells (PBMCs) at baseline and post-intervention will be collected, and their global gene expression will be analyzed by ribonucleic acid (RNA) sequencing.

  4. Change from baseline of cytokine and interferon production in PBMCs

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Monocytes isolated from human peripheral blood mononuclear cells (PBMCs) will be challenged with and without toll-like receptor ligands to assess cytokine and interferon production in low- and high-stress subjects at baseline and after intervention.

  5. Change from baseline of cytotoxicity of peripheral natural killer cells

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    The cytotoxicity of peripheral natural killer (NK) cells isolated from subject's peripheral blood mononuclear cells (PBMCs) of low- and high-stress individuals at baseline and after intervention will be assessed using an ex vivo cytotoxicity assay with human erythroleukemic cell line (K562) target cells.

  6. Change from baseline of interferon-gamma

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Interferon-gamma (IFN-γ) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  7. Change from baseline of tumor necrosis factors alpha and beta

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Tumor necrosis factors alpha and beta (TNF-α, TNF-β) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  8. Change from baseline of interleukins

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    A panel of interleukins: (IL) (IL-1α, IL-1β, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-10, IL-12/IL-23p40, IL-12p70, IL-13, IL-15, IL-16, IL-17A) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  9. Change from baseline of fibroblast growth factor

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Fibroblast growth factor (FGF) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  10. Change from baseline of granulocyte-macrophage colony-stimulating factor

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Granulocyte-macrophage colony-stimulating factor (GM-CSF) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery:

  11. Change from baseline of thymus and activation-regulated chemokine

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Thymus and activation-regulated chemokine (TARC). will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  12. Change from baseline of macrophage inflammatory proteins-1 alpha and beta

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Macrophage inflammatory proteins-1 alpha and beta (MIP-1α, MIP-1β) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  13. Change from baseline of macrophage-derived chemokine

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Macrophage-derived chemokine (MDC) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  14. Change from baseline of monocyte chemoattractant proteins-1 and -4

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Monocyte chemoattractant proteins-1 and -4 (MCP-1, MCP-4) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  15. Change from baseline of interferon gamma-induced protein-10

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Interferon gamma-induced protein-10 (IP-10) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  16. Change from baseline of eotaxin and eotaxin-3

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Eotaxin and eotaxin-3 will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  17. Change from baseline of C-reactive protein

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    C-reactive protein (CRP) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  18. Change from baseline of intercellular adhesion molecule-1

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Intercellular adhesion molecule-1 (ICAM-1) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  19. Change from baseline of placental growth factor

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Placental growth factor (PlGF) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  20. Change from baseline of serum amyloid A

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Serum amyloid A (SAA) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  21. Change from baseline of angiopoietin-1 receptor

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Angiopoietin-1 receptor (Tie-2) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  22. Change from baseline of vascular cell adhesion molecule-1

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Vascular cell adhesion molecule-1 (VCAM-1) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  23. Change from baseline of vascular endothelial growth factors A, C, and D

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Vascular endothelial growth factors A, C, and D (VEGF-A, VEGF-C, VEGF-D) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  24. Change from baseline of vascular endothelial growth factor receptor-1

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Vascular endothelial growth factor receptor-1 (VEGFR-1/Flt-1) will be measured before and after each intervention using the V-PLEX Human Biomarker 40-Plex Kit from Meso Scale Discovery

  25. Change from baseline of monocyte phenotype

    Time frame: Baseline, 4 weeks, 8 weeks, 12 weeks

    Classical monocytes, intermediate monocytes, and non-classical monocytes, will be identified by leukocyte common antigen (CD45+), Low-density lipoprotein receptor-related protein 1 (CD91+), cluster of differentiation 14 (CD14), cluster of differentiation 16 (CD16), and cluster of differentiation 3 (lin-CD3)/cluster of differentiation 66b (CD66b)/neural cell adhesion molecule (CD56)/cluster of differentiation 19 (CD19) using flow cytometry.

  26. Change from baseline of monocyte functional profile

    Time frame: Baseline, 4 weeks, 8 weeks, 12 weeks

    Cellular activation of classical monocytes, intermediate monocytes, and non-classical monocytes will be assessed by expression of cluster of differentiation 11b (CD11b) and cluster of differentiation 163 (CD163).

  27. Change from baseline of natural killer cell phenotype

    Time frame: Baseline, 4 weeks, 8 weeks, 12 weeks

    Natural killer (NK) cells will be identified by CD45+, cluster of differentiation 56+ (CD56+), and lin-CD3/CD66b/CD14/CD19 using flow cytometry.

  28. Change from baseline of natural killer cell functional profile

    Time frame: Baseline, 4 weeks, 8 weeks, 12 weeks

    Natural killer (NK) cell maturation status and cytotoxic potential via CD16, cluster of differentiation 57 (CD57), killer cell lectin-like receptor K1 (NKG2D), and cluster of differentiation 159 (NKG2A) will be analyzed using flow cytometry.

Secondary outcomes

  1. Changes in stool consistency

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Participants will provide stool samples at 4 times throughout the study. Stool samples will be used to confirm the stool consistency reported by the study subject.

  2. Changes in stool metrics

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Participants will provide stool samples at 4 times throughout the study. Stool samples will be used to determine the whole stool weight.

  3. Changes in bowel movement frequency

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    During the week prior to each intervention and the final week of each intervention, participants will maintain a stool diary for recording frequency of bowel movements.

  4. Changes in Gastrointestinal (GI) symptoms

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    During the week prior to each intervention and the final week of each intervention, a short GI Symptoms Questionnaire will be administered via Qualtrics to record occurrence of gastric symptoms.

  5. Changes in gut microbial diversity

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Participants will provide stool samples at 4 times throughout the study. Stool samples will be used to determine the microbial community composition by 16-subunit ribosomal ribonucleic acid (16S rRNA) amplicon sequence analysis.

  6. Changes in stool short chain fatty acids

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Participants will provide stool samples at 4 times throughout the study. Stool samples will be used to measure the amount of fecal short chain fatty acids (SCFAs).

  7. Changes in gut inflammatory markers

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Participants will provide stool samples at 4 times throughout the study. Stool samples will be used to measure the inflammatory marker, fecal calprotectin.

  8. Change in salivary cortisol

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    To assess waking and diurnal cortisol fluctuations, saliva will be collected at home at selected times upon waking and before bedtime. The waking saliva sample must be collected within 10-15 minutes of waking. Following the waking sample, participants will be asked to collect additional saliva samples at 15, 30, 45, and 60 minutes after the waking sample, as well as a saliva sample before bedtime.

    In total, participants will return 24 saliva samples (6 per visit) throughout the study.

  9. Change in urinary cortisol levels

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Before and after each intervention, 12-hour overnight urinary cortisol will be measured.

  10. Change in urinary epinephrine levels

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Before and after each intervention, 12-hour overnight urinary epinephrine levels will be measured.

  11. Change in urinary norepinephrine levels

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Before and after each intervention, 12-hour overnight urinary norepinephrine levels will be measured.

  12. Change in urinary creatinine levels

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Before and after each intervention, 12-hour overnight urinary creatinine levels will be measured.

  13. Change in resting blood pressure

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Research team will collect resting blood pressure (systolic and diastolic) in mmHg (millimeters of mercury).

  14. Change in dietary intake

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Dietary intake will be assessed by using the Automated Self-Administered 24-hour (ASA24®) dietary assessment tool, a web-based tool that enables multiple, automatically coded, self-administered 24-hour recalls. Three dietary recalls will be conducted in the week preceding and the final week of each intervention period, for a total of 12, 24-hour dietary recalls.

  15. Change in Body Weight

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Research team will collect weight in kg.

  16. Change in white blood cell count

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    White blood cell (WBC) count will be measured by a DxH 520 Hematology analyzer.

  17. Change in lymphocyte count

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Lymphocyte (LY) count will be measured by a DxH 520 Hematology analyzer.

  18. Change in monocyte count

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Monocyte (MO) count will be measured by a DxH 520 Hematology analyzer.

  19. Change in neutrophil granulocyte count

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Neutrophil granulocyte (NE) count will be measured by a DxH 520 Hematology analyzer.

  20. Change in eosinophil count

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Eosinophil (EO) count will be measured by a DxH 520 Hematology analyzer.

  21. Change in basophil count

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Basophil (BA) count will be measured by a DxH 520 Hematology analyzer.

  22. Change in levels of triglycerides

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Lipid-related markers including triglycerides will be measured by auto-analyzer, Cobas Integra 400+ instrument.

  23. Change in levels of total cholesterol

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Lipid-related markers including total cholesterol will be measured by auto-analyzer, Cobas Integra 400+ instrument.

  24. Change in levels of HDL-cholesterol

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Lipid-related markers including HDL-cholesterol (HDL-C) will be measured by auto-analyzer, Cobas Integra 400+ instrument.

  25. Change in levels of LDL-cholesterol

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Lipid-related markers including LDL-cholesterol (LDL-C) will be measured by auto-analyzer, Cobas Integra 400+ instrument.

  26. Change in levels of glucose

    Time frame: Baseline, 4 weeks, 8 weeks, and 12 weeks

    Plasma glucose will be measured by auto-analyzer, Cobas Integra 400+ instrument.

Study contacts

Contact information is provided by the study sponsor or research team.

Ellen Bonnel, PhD

CONTACT

[email protected]

530-752-4184

Ione Summers, BSc

CONTACT

[email protected]

530-754-8544

Sponsors and collaborators

Lead sponsor

USDA, Western Human Nutrition Research Center

Fed

Registry information

Official study title

Effects of Peanut Consumption on Physiological and Psychosocial Stress, Circulating Immune Cell Status, Markers of Inflammation and Cardiovascular Disease Risk, and Gastrointestinal Health in High-Stress Individuals

Important dates

Study start
2026
Primary completion
2028
Study completion
2028
First posted
Jul 29, 2026
Registry last updated
Aug 3, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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