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NCT Number: NCT07235358

Cardiometabolic Effects of Pecan Snacking in Prediabetes

The purpose of this study is to investigate the effects of replacing snacks higher in saturated fats and added sugars with pecans on blood sugar control, heart health and diet quality in individuals with prediabetes. Participants will be randomized into one of two groups. Group 1 will consume 1.5 oz of pecans per day in place of normally consumed snacks higher in saturated fat and added sugars for 16 weeks. Group 2 will be asked to continue consuming their current diet for 16 weeks. Measures will be taken to evaluate blood sugar, heart health and dietary intake at the beginning and 16 weeks later.

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Key information

Conditions

PreDiabetes Cardiovascular Diseases Diabetes Mellitus Endocrine System Diseases Glucose Metabolism Disorders Metabolic Diseases Nutritional and Metabolic Diseases Prediabetic State

Age range

25 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

The Pennsylvania State University

University Park, Pennsylvania, 16802, United States

Location status: Recruiting

Location contact

Kristina Petersen, PhD

CONTACT

[email protected]

814-865-7206

About this study

This is a 16-week randomized controlled trial. Participants will be randomized to either: 1) replace current snacks higher in saturated fat and added sugars with 1.5 oz/day of pecans; 2) continue their habitual diet. At the beginning and the end of the 16-week study period, testing will be conducted.

Who can participate

Healthy volunteers accepted: No

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

Inclusion criteria

  • Age 25-65 years
  • Prediabetes assessed by an HbA1c of 5.7-6.4% at screening
  • BMI 25-40 kg/m2 at screening
  • Low habitual nut consumption (<3.5 oz-eq/week) assessed at the telephone screening
  • Regularly eats snacks higher in saturated fat and/or added sugars assessed at the telephone screening

Exclusion criteria

  • LDL-C ≥190 mg/dL at screening
  • Hemoglobin <13.2 g/dL at screening
  • Fasting triglycerides >350 mg/dL at screening
  • ≥10% change in body weight within the 6 months prior to enrollment
  • Blood pressure >140/90 mmHg at screening
  • Type 1 or type 2 diabetes
  • Prescription of anti-hypertensive, lipid-lowering, or glucose-lowering drugs
  • Intake of supplements or over-the-counter medications that affect the outcomes of interest (i.e., lipid, blood pressure, or glucose lowering; vitamin C or multi-vitamins containing vitamin C) and are unwilling to cease during the study period.
  • History of liver, kidney, or autoimmune disease
  • Prior cardiovascular event (e.g., stroke, heart attack)
  • Current pregnancy or intention of pregnancy within the next 12 months
  • Lactation within the prior 6 months
  • Pecan allergy/intolerance/sensitivity/dislike
  • Unwilling/unable to eat 1.5 oz of pecans every day as a snack during the duration of the study
  • Antibiotic use within the prior 4 weeks
  • Oral steroid use within the prior 4 weeks
  • Use of tobacco or nicotine-containing products within the past 6 months
  • History of cancer at any site within the past 10 years (eligible if ≥10 years without recurrence) or non-melanoma skin cancer within the past 5 years (eligible if ≥5 years without recurrence)
  • Participation in another clinical trial within 60 days of baseline
  • Unwilling to contact study staff before enrolling in other health-related research and avoid participating in any research that may interfere with this study.
  • Currently following a restricted or weight-loss diet
  • Prior bariatric surgery
  • Intake of >14 alcoholic drinks/week and/or not willing to avoid alcohol consumption for 48 hours prior to test visits
  • Principal Investigator discretion related to the potential participant's ability to adhere to the study requirements, including being able to come to attend visits
  • Does not speak and/or understand English
  • Unwilling to refrain from donating blood or plasma during the study
  • Weight <110 lb
  • If a potential participant takes thyroid medicine, abnormal thyroid stimulated hormone (TSH) concentration (TSH outside of normal range), or change in dose of thyroid medication within the last 6 months

Treatment and study plan

Pecan snacking

Behavioral

Replacement of typically consumed snacks with 1.5 oz/day of pecans

Usual diet

Other

Continue with usual diet

Primary outcomes

  1. Change in HbA1c

    Time frame: 16 weeks

    HbA1c will be assessed at baseline and 16-weeks and expressed as percentage . The change in HbA1c will be calculated by subtracting the baseline value from the 16 week value and expressed as percentage point change.

Secondary outcomes

  1. Change in fasting glucose

    Time frame: 16 weeks

    Change in fasting plasma glucose expressed as mg/dL. Change in glucose will be calculated as the mean of the 16 week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).

  2. Change in mean glucose

    Time frame: 16 weeks

    Change in mean glucose assessed by a continuous glucose monitor (CGM) expressed as mg/dL. Change in mean glucose will be calculated as mean glucose assessed from 7 days of CGM wear at 16 weeks minus mean glucose assessed from 7 days of CGM wear at baseline.

  3. Change in mean time in range

    Time frame: 16 weeks

    Change in mean time in range (glucose 70-140 mg/dL) assessed by a continuous glucose monitor (CGM) expressed as minutes per day. Change in mean time in range will be calculated as mean time in range assessed from 7 days of CGM wear at 16 weeks minus mean time in range assessed from 7 days of CGM wear at baseline.

  4. Change in glycemic variability

    Time frame: 16 weeks

    Change in mean glycemic variability assessed by a continuous glucose monitor (CGM) expressed as the coefficient of variability. Change in mean glycemic variability will be calculated as mean glycemic variability assessed from 7 days of CGM wear at 16 weeks minus mean glycemic variability assessed from 7 days of CGM wear at baseline.

  5. Change in fasting insulin

    Time frame: 16 weeks

    Change in fasting serum insulin expressed as micro IU/mL. Change in insulin will be calculated as the mean of the 16 week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).

  6. Change in homeostatic model of insulin resistance (HOMA-IR)

    Time frame: 16 weeks

    Homeostatic model of insulin resistance (HOMA-IR) will be calculated from insulin and glucose measured from a fasting blood sample. Calculated as (insulin × glucose) / 22.5. Change in HOMA-IR will be calculated as the mean of the 16 week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).

  7. Change in the lipoprotein insulin resistance index

    Time frame: 16 weeks

    The lipoprotein insulin resistance index will be calculated from Nuclear Magnetic Resonance assessed lipoprotein concentrations according to a previously described method: Metab, Syndr. Relat. Disord. 12 (8) (2014) 422-429. Change will be calculated by subtracting the baseline value from the 16 week value.

  8. Change in LDL-Cholesterol

    Time frame: 16 weeks

    Assessed from fasting blood draw expressed in mg/dL. Change in LDL-cholesterol will be calculated as the mean of the 16-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).

  9. Change in apolipoprotein B

    Time frame: 16 weeks

    Assessed from fasting blood draw expressed in mg/dL. Change in apolipoprotein B will be calculated by subtracting the baseline value from the 16 week value.

  10. Change in non-HDL cholesterol

    Time frame: 16 weeks

    Assessed from fasting blood draw expressed in mg/dL. Change in non-HDL cholesterol will be calculated as the mean of the 16-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).

  11. Change in Total Cholesterol

    Time frame: 16 weeks

    Assessed from fasting blood draw expressed in mg/dL. Change in total cholesterol will be calculated as the mean of the 16-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).

  12. Change in HDL-Cholesterol

    Time frame: 16 weeks

    Assessed from fasting blood draw expressed in mg/dL. Change in HDL-cholesterol will be calculated as the mean of the 16-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).

  13. Change in Triglycerides

    Time frame: 16 weeks

    Assessed from fasting blood draw expressed in mg/dL. Change in triglycerides will be calculated as the mean of the 16-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).

  14. Change in C-reactive protein

    Time frame: 16 weeks

    Assessed from fasting blood draw expressed in mg/L. Change in C-reactive protein will be calculated as the mean of the 16-week measures (i.e., mean of day 1 and day 2 values) minus the mean of the baseline measures (i.e., mean of day 1 and day 2 values).

  15. Change in Central Systolic and Diastolic Blood Pressure

    Time frame: 16 weeks

    Central blood pressure measured assessed using a SphymoCor Xcel (Atcor Medical) at baseline & 16 weeks. Change will be calculated by subtracting the baseline value from the end point value.

  16. Change in Peripheral Systolic and Diastolic Blood Pressure

    Time frame: 16 weeks

    Peripheral blood pressure measured assessed using a SphymoCor Xcel (Atcor Medical) at baseline & 16 weeks. Change will be calculated by subtracting the baseline value from the end point value.

  17. Change in Carotid-Femoral Pulse Wave Velocity

    Time frame: 16 weeks

    Measured assessed using a SphymoCor Xcel (Atcor Medical) at baseline & 16 weeks. Change will be calculated by subtracting the baseline value from the end point value.

  18. Change in particle size and number of LDL, HDL, triglyceride rich lipoproteins

    Time frame: 16 weeks

    Measured via Nuclear Magnetic Resonance at baseline and 16 weeks. The change will be calculated by subtracting the baseline value from the 16 week value.

  19. Change in Saturated fat intake

    Time frame: 16 weeks

    Assessed from 24-hour recalls completed prior to baseline and at 16 weeks. Change in saturated fat will be calculated as saturated fat intake at 16 weeks minus baseline saturated fat intake.

  20. Change in added sugar intake

    Time frame: 16 weeks

    Assessed from 24-hour recalls completed prior to baseline and at 16 weeks. Change in added sugar intake will be calculated as added sugar intake at 16 weeks minus baseline added sugar intake.

  21. Change in diet quality

    Time frame: 16 weeks

    Assessed from 24-hour recalls completed prior to baseline and at 16 weeks. Diet quality will be calculated according to the Healthy Eating Index-2020 (HEI). Change in HEI will be calculated as HEI at 16 weeks minus baseline HEI.

Study contacts

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

Kristina Petersen, PhD

CONTACT

[email protected]

814-865-7206

Stacey Meily

CONTACT

[email protected]

814-863-8622

Sponsors and collaborators

Lead sponsor

Penn State University

Other

Collaborators

  • American Pecan Promotion Board

Registry information

Official study title

Glycemic Effects of Substituting Pecans for Snacks Higher in Saturated Fat and Added Sugars in Individuals With Prediabetes

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Nov 19, 2025
Registry last updated
May 27, 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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