Recruiting

Protein Smoothies

Sponsor:

University of Pittsburgh

Code:

NCT07121010

Conditions

Cardiometabolic Health

Eligibility Criteria

Sex: All

Age: 18 - 65

Healthy Volunteers: Accepted

Interventions

Animal-Based Protein Smoothie

Plant-Based Protein Smoothie

Plant-Based Protein Smoothie with Leucine

Study Details

Brief summary:

The goal of this clinical trial is to learn how different protein types affect the body's metabolism and immune system in healthy adults. The main questions it aims to answer are:

Does drinking smoothies with animal-based or plant-based protein change the level of amino acids like leucine in the blood?

Does adding leucine to a plant-based smoothie make the body respond like it does to an animal-based smoothie?

Participants will:

Come to the research clinic for 3 study visits

Drink a high-protein smoothie at each visit (one with animal protein, one with plant protein, and one with plant protein + leucine)

Give blood samples before and 1 and 3 hours after each smoothie

Researchers will look at how the body's metabolism and immune system respond. They are especially interested in a pathway called mTOR, which helps control how cells use nutrients and may be involved in heart disease like atherosclerosis.

All smoothies are prepared to meet Halal and Kosher dietary guidelines.

Conditions

Cardiometabolic Health

Study ID

NCT07121010

Start date

Mar 24, 2026

Status verified date

Mar, 2026

Completion date

Oct, 2026

Anticipated

Primary completion date

Sep, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18 - 65

Healthy Volunteers: Accepted

Inclusion Criteria:

1. Age 18-65 years
2. BMI 18.5-29.9 kg/m²
3. Generally healthy, without known chronic illness and/or treatment with chronic medications
4. Willing to comply with dietary restrictions and study procedures
5. Not currently following a prescribed or restrictive diet (for example, vegan, ketogenic or high-protein regimen) or regularly taking high-protein supplements

Exclusion Criteria:

1. History of cardiovascular disease, diabetes, or autoimmune disorders
2. Active use of anti-inflammatory, immunomodulatory, or lipid-lowering medications
3. Renal or hepatic dysfunction
4. Pregnancy or breastfeeding
5. Allergies or intolerances to components of study meals. A list of the smoothie ingredients will be sent to the potential participant with the mailing of the consent form
6. Participation in another interventional study within the last 30 days

Study Design

Enrollment

20 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Basic Science

Interventions and Outcome Measures

Arms

experimental: Animal → Plant → Plant+Leucine

Participants in this arm will receive the animal-based protein smoothie during their first visit, the plant-based protein smoothie during their second visit, and the plant-based protein smoothie with added leucine during their third visit. All study visits follow the same protocol, including fasting, blood draws, and postprandial assessments.

experimental: Plant-Based → Plant-Based with Leucine → Animal-Based

Participants in this arm will receive the plant-based protein smoothie first, the plant-based protein smoothie with leucine second, and the animal-based protein smoothie third. All clinical procedures are the same across visits.

experimental: Plant-Based with Leucine → Animal-Based → Plant-Based

Participants in this arm will receive the plant-based protein smoothie with leucine at their first visit, the animal-based smoothie second, and the plant-based protein smoothie third. The same procedures will be followed at each visit.

Interventions

Animal-Based Protein Smoothie

This smoothie is formulated to deliver 50% of its total caloric content from high-quality animal-based protein, such as whey protein isolate or pasteurized egg whites. It is designed to evaluate the postprandial metabolic and immune response to animal-derived protein sources. The smoothie does not contain any added free amino acids and is prepared in a food-safe certified kitchen under standardized conditions. All participants consume the smoothie after an overnight fast to ensure consistency in metabolic assessment.

Plant-Based Protein Smoothie

This smoothie is formulated to deliver 50% of its total caloric content from plant-based protein, such as pea or rice protein isolate. It is designed to evaluate the postprandial metabolic and immune response to plant-derived protein sources. The smoothie does not contain any added free amino acids and is prepared in a food-safe certified kitchen under standardized conditions. All participants consume the smoothie after an overnight fast to ensure consistency in metabolic assessment.

Plant-Based Protein Smoothie with Leucine

This smoothie is formulated to deliver 50% of its total caloric content from plant-based protein, using sources such as pea or rice protein isolate. In addition, it is supplemented with pharmaceutical-grade leucine to match the leucine content typically found in animal-based protein sources. The smoothie is designed to assess whether leucine supplementation can modulate the postprandial metabolic and immune response to plant-derived protein. It is prepared in a food-safe certified kitchen and consumed after an overnight fast to maintain consistency across study conditions.

Primary outcome measure

  • Change in Circulating Serum Leucine Concentration [ Time Frame: From enrollment to final blood draw at 4 weeks ]

Central Contacts and Locations

Central contacts

Ali Ajam, MD

412-512-1044ala449@pitt.edu

Babak Razani, MD-PhD

412-648-7496brazani@pitt.edu

Locations

UPMC Montefiore - Clinical and Translational Research Center (CTRC)

Recruiting

Pittsburgh, Pennsylvania, United States, 15213

More Information

Sponsor

University of Pittsburgh

Last update posted

Mar 25, 2026

Last verified

Mar, 2026

Keywords

  • mTOR Signaling
  • Dietary Protein
  • Cardiometabolic Disease
  • Atherosclerosis
  • Nutrient Signaling

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-10. This information was provided to ClinicalTrials.gov by University of Pittsburgh on 2026-03-25.