Cardiometabolic Effects of Low-Fat and Full-Fat Dairy

May 18, 2026 updated by: Kristina Petersen PhD, APD, FAHA, Penn State University

Cardiometabolic Effects of Low-Fat and Full-Fat Dairy in Healthy and Cardiometabolically At-Risk Adults

The purpose of this study is to find out if full-fat dairy and low-fat dairy have similar effects on risk factors for heart disease and diabetes. During the study, participants will consume two types of dairy products: low-fat dairy (milk, yogurt, and cheese) and full-fat dairy (milk, yogurt, and cheese). Each type of dairy will be consumed for 6 weeks with a ≥4-week break between. Measures will be taken to evaluate blood cholesterol, blood sugar, body weight, inflammation, blood pressure, heart health and dietary intake at the beginning and end of each 6 week period.

Study Overview

Status

Not yet recruiting

Conditions

Intervention / Treatment

Detailed Description

The overarching goal of this clinical trial is to characterize and compare the effect of full-fat dairy to low-fat dairy on low density lipoprotein cholesterol (LDL-C) and other cardiometabolic disease (CMD) risk factors in healthy adults and those at risk for CMD. This goal will be achieved with the following objectives:

  1. Characterize the effect of full-fat dairy compared to low-fat dairy on LDL-C and other CMD risk factors in healthy adults and adults at risk for CMD after 6 weeks.
  2. Compare the effect of full-fat dairy to low-fat dairy in healthy adults vs. adults at risk for CMD after 6 weeks.

This clinical trial will test two hypotheses: 1) intake of 3 cup-equivalents/day of full-fat dairy (milk, yogurt & cheese) has equivalent effects on LDL-C and other CMD risk factors to 3 cup-equivalents/day of low-fat dairy (milk, yogurt & cheese) in adults with normal BMI and optimal/near optimal LDL-C, and in adults with overweight/obesity and elevated LDL-C after 6 weeks; 2) the effect of full-fat dairy on LDL-C and other CMD risk factors, compared to low-fat dairy, is equivalent in adults with normal BMI and optimal/near optimal LDL-C compared to adults with overweight/obesity and elevated LDL-C after 6 weeks. This trial is expected to demonstrate equivalent effects of full-fat and low-fat dairy on LDL-C and other CMD risk factors in both healthy and at-risk adults.

This is a randomized clinical trial with 2 groups of adults. Group 1 will include adults with normal BMI (18.5 -24.9 kg/m2) and optimal/near optimal LDL-C (≤ 129 mg/dL). Group 2 will include adults with overweight/obesity (25-39.9 kg/m2) and elevated LDL-C (130-190 mg/dL). Within each group, subjects will undergo two 6-week dietary conditions in random sequence order, separated by a 4-week washout: 1) 3 cup-equivalents/day of full-fat dairy; 2) 3 cup-equivalents/day of low-fat dairy. Outcomes will be assessed at the start and end of each period.

Study Type

Interventional

Enrollment (Estimated)

178

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

  • Name: Kristina Petersen, PhD
  • Phone Number: 814-865-7206
  • Email: kup63@psu.edu

Study Contact Backup

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

Yes

Description

Inclusion Criteria:

  • BMI 18.5 to 39.9 kg/m2
  • LDL-C ≤190 mg/dL assessed by the Modified Sampson-NIH Equation
  • Currently consume milk, yogurt, and/or cheese daily
  • Willing to eat 3 servings of dairy (milk, yogurt, cheese) for two 6-week periods during 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
  • ≥10% change in body weight within the 6 months prior to enrollment
  • Blood pressure >140/90 mmHg at screening
  • Fasting glucose ≥126 mg/dL
  • Type 1 or type 2 diabetes
  • Takes any (prescription or over-the-counter) anti-hypertensive, lipid-lowering, glucose-lowering or anti-inflammatory drugs, or drugs that alter body weight
  • Intake of supplements that affect the outcomes of interest (i.e., lipids, blood pressure, glucose, body weight, inflammation 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
  • 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
  • Dairy 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
  • Lactose intolerance or sensitivity
  • 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

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

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

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Healthy Adults
Adults with normal BMI (18.5 -24.9 kg/m2) and optimal/near optimal LDL-C (≤ 129 mg/dL).
Other: Full-fat dairy
3 cup-equivalents/day of full-fat dairy (milk, yogurt & cheese)
Other: Low-fat dairy
3 cup-equivalents/day of low-fat dairy (milk, yogurt & cheese)
Experimental: Adults at risk for cardiometabolic diseases
Adults with overweight/obesity (25-39.9 kg/m2) and elevated LDL-C (130-190 mg/dL
Other: Full-fat dairy
3 cup-equivalents/day of full-fat dairy (milk, yogurt & cheese)
Other: Low-fat dairy
3 cup-equivalents/day of low-fat dairy (milk, yogurt & cheese)

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
LDL-cholesterol change
Time Frame: 6 weeks
Assessed from fasting blood draw expressed in mg/dL. LDL-cholesterol will be calculated via the Modified Sampson-NIH Equation. Change in LDL-cholesterol will be calculated as the mean of the end of intervention measures (i.e., mean of day 1 and day 2 values) minus the mean of the pre-intervention measures (i.e., mean of day 1 and day 2 values).
6 weeks

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Apolipoprotein B change
Time Frame: 6 weeks
Assessed from fasting blood draw expressed in mg/dL.
6 weeks
Triglycerides change
Time Frame: 6 weeks
Assessed from fasting blood draw expressed in mg/dL.
6 weeks
Total cholesterol change
Time Frame: 6 weeks
Assessed from fasting blood draw expressed in mg/dL.
6 weeks
HDL-cholesterol change
Time Frame: 6 weeks
Assessed from fasting blood draw expressed in mg/dL.
6 weeks
non-HDL cholesterol change
Time Frame: 6 weeks
Assessed from fasting blood draw expressed in mg/dL.
6 weeks
Glucose change
Time Frame: 6 weeks
Assessed from fasting blood draw expressed in mg/dL.
6 weeks
Insulin change
Time Frame: 6 weeks
Assessed from fasting blood draw expressed in micro IU/ml.
6 weeks
Fructosamine change
Time Frame: 6 weeks
Assessed from fasting blood draw expressed in umol/L.
6 weeks
Homeostatic model of insulin resistance (HOMA-IR) change
Time Frame: 6 weeks
Calculated from insulin and glucose measured from a fasting blood sample. Calculated as (insulin × glucose) / 22.5
6 weeks
C-reactive protein change
Time Frame: 6 weeks
Assessed from fasting blood draw expressed in mg/L.
6 weeks
Body weight change
Time Frame: 6 weeks
Measured in the fasting state using a calibrated electronic scale.
6 weeks
Brachial systolic and diastolic blood pressure change
Time Frame: 6 weeks
Measured in the fasting state using a SphymoCor Xcel (Atcor Medical)
6 weeks
Central systolic and diastolic blood pressure change
Time Frame: 6 weeks
Measured in the fasting state using a SphymoCor Xcel (Atcor Medical)
6 weeks
Carotid-femoral pulse wave velocity change
Time Frame: 6 weeks
Measured in the fasting state using a SphymoCor Xcel (Atcor Medical)
6 weeks
Diet quality change
Time Frame: 6 weeks
Healthy Eating Index-2020 assessed using 24-hour recalls
6 weeks

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Penn State University

Investigators

  • Principal Investigator: Kristina Petersen, PhD, The Pennsylvania State University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

September 8, 2026

Primary Completion (Estimated)

August 31, 2028

Study Completion (Estimated)

August 31, 2028

Study Registration Dates

First Submitted

May 18, 2026

First Submitted That Met QC Criteria

May 18, 2026

First Posted (Actual)

May 26, 2026

Study Record Updates

Last Update Posted (Actual)

May 26, 2026

Last Update Submitted That Met QC Criteria

May 18, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • DAIRY

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Sharing Time Frame

Study protocol and SAP will be uploaded to clinicaltrials.gov prior to enrollment of the first participant

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

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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