Health Properties of Pecan Nut Consumption

Assessment of Systematic Health Properties of Pecan Nut Consumption: Gut, Vascular, Metabolic and Cognitive Outcomes

The main goal of this clinical study is to see if consuming pecan nuts will result in improvements in overall body metabolism such as in blood lipids, markers of inflammation, blood pressure, cognitive performance and changes in bacteria living in the gut in adults 45 to 75 years of age.

Participants will take part in two 3-month intervention periods, separated by 4-6 weeks, in random order ( a total of approximately 7 months). During one intervention period, they will include pecan nuts in their diet each day, while during the other intervention period they will avoid pecans in their diet. There will be an initial screening visit to evaluate eligibility and four study visits to the clinic.

Participants will be asked to complete some questionnaires about their diet, physical and cognitive health, and provide blood and stool samples, and have their blood pressure measured.

Study Overview

• Status: Recruiting
• Conditions: Healthy Adults
• Intervention / Treatment: Other: pecan nut

• Study Type: Interventional
• Enrollment (Estimated): 40
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Francene Steinberg, PhD; Phone Number: 530-752-0160; Email: fmsteinberg@ucdavis.edu

Study Locations

• United States
  • California
    • Davis, California, United States, 95616
      • Recruiting
      • Ragle Human Nutrition Center, UC Davis campus
      • Contact: Francene Steinberg, PhD; Phone Number: 530-752-0160; Email: fmsteinberg@ucdavis.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: Yes

Description

Inclusion Criteria:

BMI of 20-35 kg/m2, ability to understand the intervention instructions, Willingness to follow the dietary intervention, Willingness to provide biological samples (blood and stool) -

Exclusion Criteria:

Allergy to pecan or other nuts, Cognitive impairment due to dementia of any type and inability to understand or comply with intervention instructions, Use of menopausal hormone replacement therapy, Use of antibiotics or probiotics in the 2 months prior to enrollment, Uncontrolled diabetes with HbA1C of >9.5, Vegetarian/vegan, Any serious medical condition (such as chronic kidney disease of stage 3 or greater, heart failure, active cancer treatment, inflammatory bowel disease, etc.), Consumption of supplements that may interfere with vascular response or gut microbiome, Use of statin drugs for cholesterol lowering.

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Study Plan

How is the study designed?

Design Details

• Primary Purpose: Prevention
• Allocation: Randomized
• Interventional Model: Crossover Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Pecan nut then no nut; Participant will add pecan nuts to their diet during the first intervention arm, then they will cross over to the no nut diet arm	Other: pecan nut; Dose - 2 ounces of pecan nuts, daily
Experimental: No nut then pecan nut; Participant will consume a diet without nuts during the first intervention arm, then they will cross over to the arm where they will add pecan nuts to their diet.	Other: pecan nut; Dose - 2 ounces of pecan nuts, daily

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in vascular response at 3 months	Vascular response as measured by Pulse Wave Velocity (PWV)	Change from baseline at 3 months

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in blood lipids over 3 months	Blood lipids as measured by clinical lipid panel, including total, LDL and HDL cholesterol, and Tiglycerides	Change from baseline at 3 months
Change in markers of inflammation at 3 months	Markers of inflammation as measured by Luminex cytokine panel IL-17	change from baseline at 3 months
Change in gut microbiome profile at 3 months	Gut microbiome profile as measured by fecal 16S rRNA gene sequencing	Change from baseline at 3 months
Change in blood markers of intestinal permeability at 3 months.	Blood marker of intestinal permeability as measured by ELISA for LBP and LPS	Change from baseline at 3 months
Change in blood markers of intestinal permeability at 3 months	Blood biomarker of intestinal permeability and immune activation as measured by ELISA of sCD14	Change from baseline at 3 months
Change in cognitive function - reaction time at 3 months	Reaction time task as measured by CANTAB assessments	Change from baseline at 3 months
Change in cognitive function - working memory at 3 months	Spatial working memory as assessed by CANTAB	Change from baseline at 3 months
Change in cognitive function - episodic memory at 3 months	Paired associates learning as measured by CANTAB	Change from baseline to 3 months
Change in cognitive function - sustained attention at 3 months	Attention measured via Rapid visual information processing using CANTAB	Change from baseline at 3 months
Change in quality of life at 3 months	Self-perceived quality of life questionnaire assessed using World Health Organization Qualigy of Life Instruments (WHOQOL-BREF)	Change from baseline at 3 months
Change in sleep quality at 3 months	Self-rated questionnaire of sleep quality measured by Pittsburgh Sleep Quality Index (PSQI)	Change from baseline at 3 months
Change in mood over 3 months	Assessment of mood using the Affect Grid	Change from baseline to 3 months
Change in perceived stress over 3 months	Assessment of stress using the Perceived Stress Scale (PSS-10)	Change from baseline at 3 months
Change in anxiety at 3 months	Anxiety measured using the Generalized Anxiety disorder Scale (GAD-7)	Change from baseline at 3 months
Change in depressive symptoms at 3 months	Assessment of depressive symptoms using the Beck Depression Inventory-II (BDI-II)	Change from baseline at 3 months
Change in blood acute phase inflammatory response maker at 3 months	Acute phase inflammatory response measured by hsCRP	Change from baseline at 3 months

Collaborators and Investigators

• Sponsor: University of California, Davis

Study record dates

Study Major Dates

• Study Start (Actual): November 15, 2025
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: November 9, 2025
• First Submitted That Met QC Criteria: November 9, 2025
• First Posted (Actual): November 12, 2025

Study Record Updates

• Last Update Posted (Actual): February 24, 2026
• Last Update Submitted That Met QC Criteria: February 20, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Keywords: gut microbiome; cardiovascular; cognitive; pecan nut
• Other Study ID Numbers: 2340870

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No