Cardiometabolic & Cognitive Effects of Peanut Butter in Prediabetes

Peanut Butter Glycemic Control, Cognition and Cardiovascular Health

The purpose of this study is to look at the effect of consuming peanut butter at breakfast on blood sugar control, cognitive function, and heart disease risk factors in middle-aged adults with prediabetes.

Study Overview

• Status: Not yet recruiting
• Conditions: Prediabetes
• Intervention / Treatment: Other: Peanut butter; Other: Usual diet

Detailed Description

This is a 2-period, randomized, crossover study. In random sequence order participants will undergo each of the following conditions for 12 weeks with a ≥ 8-week washout between the two periods: 1) provision of 43 g/day (1.5 oz/day) of peanut butter with instructions to consume it as part of breakfast (or the first meal of the day); 2) instructions to continue usual intake with matched study contact and resource provision. Testing will be conducted at the beginning and end of each period.

• Study Type: Interventional
• Enrollment (Estimated): 56
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Kristina Petersen, PhD; Phone Number: +1 814 865 7206; Email: kup63@psu.edu
• Study Contact Backup: Name: Stacey Meily; Phone Number: +1 814 863 8622; Email: sas117@psu.edu

Study Locations

• United States
  • Pennsylvania
    • University Park, Pennsylvania, United States, 16802
      • The Pennsylvania State University
      • Contact: Kristina Petersen, PhD; Phone Number: +1 814-865 7206; Email: kup63@psu.edu

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Age 40-65 years
• BMI 25 to 40 kg/m2
• HbA1c 5.7-6.4%
• Low habitual intake of peanut butter (<0.5 Tablespoons/day on average)
• Have a smartphone device or be willing to use one provided by the study

Exclusion Criteria:

• Hemoglobin <13.2 g/dL for men or < 11.7 g/dL for women at screening
• Fasting triglycerides >350 mg/dL at screening
• LDL-cholesterol ≥190 mg/dL assessed by the Martin-Hopkins equation at screening
• ≥10% change in body weight within the 6 months prior to enrollment
• Blood pressure >140/90 mmHg at screening
• Diagnosed type 1 or type 2 diabetes
• Takes any (prescription or over-the-counter) anti-hypertensive, lipid-lowering, glucose-lowering or body weight altering drugs
• Intake of supplements that affect the outcomes of interest (i.e., lipids, blood pressure, glucose, body weight, and microbiome) and are unwilling to cease during the study period.
• Unwilling to refrain from starting to take any supplements, vitamins, nutritional products, or health foods that are not prescribed by a doctor for the duration of the study
• Self-reported history of diagnosed liver, kidney, or autoimmune disease
• Self-reported history of a prior cardiovascular event (e.g., stroke, heart attack)
• Self-reported history of diagnosed neurological disease (e.g. Alzheimer's Disease, Parkinson's Disease, Multiple Sclerosis)
• Current pregnancy or intention of pregnancy within the next 12 months
• Lactation within the prior 6 months
• Peanut allergy/intolerance/sensitivity/dislike
• Antibiotic use within the prior four weeks
• Oral steroid use within the prior four 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
• 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
• Does not speak and/or understand English
• Unwilling to refrain from donating blood and/or plasma during the study
• Weight <110 lb
• Unwilling to contact study staff before enrolling in other health-related research and avoid participating in any research that may interfere with this study
• For individuals taking thyroid medication: abnormal thyroid stimulated hormone (TSH) concentration, or change in dose of thyroid medication within the last 6 months
• Principal Investigator discretion related to the potential participant's ability to adhere to the study requirements, including being able to come to attend visits

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: Peanut Butter-Usual Diet; In the first period, participants will be provided with 43 g/day of peanut butter with instructions to consume it at breakfast (or the first meal of the day). In the second period, participants will be instructed to continue their usual intake.	Other: Peanut butter; Intake of 43 g/day of peanut butter as part of breakfast (or the first meal of the day); Other: Usual diet; Continue intake of usual diet.
Active Comparator: Usual Diet-Peanut Butter; In the first period, participants will be instructed to continue their usual intake. In the second period, participants will be provided with 43 g/day of peanut butter with instructions to consume it at breakfast (or the first meal of the day).	Other: Peanut butter; Intake of 43 g/day of peanut butter as part of breakfast (or the first meal of the day); Other: Usual diet; Continue intake of usual diet.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in HbA1c	HbA1c will be assessed at the beginning and end of each 12-week period and expressed as percentage. The change in HbA1c will be calculated as the post-condition value minus the pre-condition value and expressed as percentage point change.	12 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in fasting glucose	Change in fasting plasma glucose expressed as mg/dL. Change in glucose will be calculated as the mean of the post-condition day 1 and day 2 testing values minus the mean of the pre-condition day 1 and day 2 testing values.	12 weeks
Change in fasting insulin	Change in fasting serum insulin expressed as micro IU/mL. Change in insulin will be calculated as the mean of the post-condition day 1 and day 2 testing values minus the mean of the pre-condition day 1 and day 2 testing values.	12 weeks
Mean glucose	Mean glucose assessed by a continuous glucose monitor (CGM) expressed as mg/dL. The between-condition difference in mean glucose will be evaluated by comparing the mean glucose calculated from 7 days of CGM wear at the end of each study period.	12 weeks
Mean glucose time in range	Mean glucose time in range (70-140 mg/dL) assessed by a continuous glucose monitor (CGM) expressed as minutes per day. The between-condition difference in mean glucose time in range will be evaluated by comparing the mean glucose time in range from 7 days of CGM wear at the end of each study period.	12 weeks
Glycemic variability	Glycemic variability assessed by a continuous glucose monitor (CGM) expressed as the coefficient of variability. The between-condition difference in glycemic variability will be evaluated by comparing the glycemic variability calculated from 7 days of CGM wear at the end of each study period.	12 weeks
Change in homeostatic model of insulin resistance (HOMA-IR)	HOMA-IR will be calculated as (fasting insulin μIU/mL × fasting glucose mg/dL) / 405. Change in HOMA-IR will be calculated as the mean of the post-condition day 1 and day 2 testing values minus the mean of the pre-condition day 1 and day 2 testing values.	12 weeks
Difference in ambulatory processing speed	Ambulatory processing speed assessed by ecological momentary assessment (EMA) administered Symbol Search, expressed as median response time correct. The between-condition difference in ambulatory processing speed will be evaluated by comparing mean values from 7 days of EMA at the end of each study period.	12 weeks
Difference in ambulatory working memory	Ambulatory working memory assessed by ecological momentary assessment (EMA) administered Grid Memory, expressed as number of correct dots. The between-condition difference in ambulatory working memory will be evaluated by comparing mean values from 7 days of EMA at the end of each study period.	12 weeks
Difference in ambulatory attention	Ambulatory attention assessed by ecological momentary assessment (EMA) administered Multiple Object Tracking expressed as number of correct dots. The between-condition difference in ambulatory attention will be evaluated by comparing mean values from 7 days of EMA at the end of each study period.	12 weeks
Change in body weight	Change in body weight expressed as kg. Change in body weight will be calculated as the mean of the post-condition day 1 and day 2 testing values minus the mean of the pre-condition day 1 and day 2 testing values.	12 weeks
Difference in hunger	Hunger assessed by ecological momentary assessment (EMA) administered visual analog scale (scored 0-100). The between-condition difference in hunger will be evaluated by comparing mean values from 7 days of EMA at the end of each study period.	12 weeks
Difference in satiety	Satiety assessed by ecological momentary assessment (EMA) administered visual analog scale (scored 0-100). The between-condition difference in satiety will be evaluated by comparing mean values from 7 days of EMA at the end of each study period.	12 weeks
Change in total cholesterol	Change in fasting serum total cholesterol expressed as mg/dL. Change in total cholesterol will be calculated as the mean of the post-condition day 1 and day 2 testing values minus the mean of the pre-condition day 1 and day 2 testing values.	12 weeks
Change in LDL-cholesterol	Change in fasting serum LDL-cholesterol calculated with the Martin-Hopkins equation expressed as mg/dL. Change in LDL-cholesterol will be calculated as the mean of the post-condition day 1 and day 2 testing values minus the mean of the pre-condition day 1 and day 2 testing values.	12 weeks
Change in triglycerides	Change in fasting serum triglycerides expressed as mg/dL. Change in triglycerides will be calculated as the mean of the post-condition day 1 and day 2 testing values minus the mean of the pre-condition day 1 and day 2 testing values.	12 weeks
Change in HDL-cholesterol	Change in fasting serum HDL-cholesterol expressed as mg/dL. Change in HDL-cholesterol will be calculated as the mean of the post-condition day 1 and day 2 testing values minus the mean of the pre-condition day 1 and day 2 testing values.	12 weeks
Change in non-HDL cholesterol	Change in fasting serum non-HDL cholesterol expressed as mg/dL. Change in non-HDL cholesterol will be calculated as the mean of the post-condition day 1 and day 2 testing values minus the mean of the pre-condition day 1 and day 2 testing values.	12 weeks
Change in central systolic and diastolic blood pressure	Change in central blood pressure measured using a SphymoCor Xcel (Atcor Medical) expressed as mmHg. Change in systolic and diastolic blood pressure will be calculated as the post-condition value minus the pre-condition value and expressed as mmHg.	12 weeks
Change in peripheral systolic and diastolic blood pressure	Change in peripheral blood pressure measured using a SphymoCor Xcel (Atcor Medical) expressed as mmHg. Change in systolic and diastolic blood pressure will be calculated as the post-condition value minus the pre-condition value and expressed as mmHg.	12 weeks
Change in carotid-femoral pulse wave velocity	Change in carotid-femoral pulse wave velocity (PWV) measured using a SphymoCor Xcel (Atcor Medical) expressed as m/s. Change in PWV will be calculated as the post-condition value minus the pre-condition value and expressed as m/s.	12 weeks
Change in diet quality	Assessed from a 24-hour recall completed prior to the beginning of each study period and at the end of each study period. Diet quality will be calculated according to the Healthy Eating Index-2020 (HEI). Change in HEI will be calculated at the post-condition value minus the pre-condition value	12 weeks

Other Outcome Measures

Outcome Measure	Measure Description	Time Frame
Difference in microbiota composition	Microbiota composition assessed by 16S rRNA sequencing. The between-condition difference in microbiota composition will be evaluated by alpha and beta diversity and taxa profile at the end of each study period.	12 weeks

Collaborators and Investigators

• Sponsor: Penn State University

Study record dates

Study Major Dates

• Study Start (Estimated): January 18, 2027
• Primary Completion (Estimated): October 31, 2028
• Study Completion (Estimated): October 31, 2028

Study Registration Dates

• First Submitted: July 14, 2026
• First Submitted That Met QC Criteria: July 15, 2026
• First Posted (Actual): July 20, 2026

Study Record Updates

• Last Update Posted (Actual): July 20, 2026
• Last Update Submitted That Met QC Criteria: July 15, 2026
• Last Verified: July 1, 2026

More Information

Terms related to this study

• Keywords: diabetes; cognition; nutrition; cardiovascular disease; diet; peanut butter; heart disease; glycemic control
• Additional Relevant MeSH Terms: Endocrine System Diseases; Metabolic Diseases; Glucose Metabolism Disorders; Nutritional and Metabolic Diseases; Cardiovascular Diseases; Heart Diseases; Diabetes Mellitus; Prediabetic State
• Other Study ID Numbers: PB

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: De-identified individual participant data will be deposited into an open access repository once results from all pre-specified primary and secondary outcomes are published.
• IPD Sharing Time Frame: The SAP and protocol will be posted on clinicaltrials.gov prior to enrollment commencing.
• IPD Sharing Supporting Information Type: STUDY_PROTOCOL; SAP

Drug and device information, study documents

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