How Animal and Plant Protein Shakes Change the Body's Nutrient and Health Responses

NCT07121010 | Recruiting

• 1 other identifier: STUDY25060010
• Study Type: interventional
• Target: 20
• Locations: 1 country
• Sites: 1

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

Keywords

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

Outcome Measures

Primary Outcomes (1)

• Change in Circulating Serum Leucine Concentration

  This outcome measures the change in circulating serum leucine concentration from fasting baseline to 1 and 3 hours postprandially following ingestion of each of the three test meals: animal-based protein, plant-based protein, and plant-based protein supplemented with free leucine. Values will be compared within participants across the three meal conditions to assess how protein source and leucine content affect postprandial amino acid levels. Serum leucine will be quantified using targeted mass spectrometry. Unit of Measure: Micromoles per liter (μmol/L)

  From enrollment to final blood draw at 4 weeks

Secondary Outcomes (4)

• Change in Monocyte mTORC1 Signaling Activity

  From enrollment to final blood draw at 4 weeks

• Change in Serum IL-6 Concentration

  From enrollment to final blood draw at 4 weeks

• Change in Serum TNF-α Concentration

  From enrollment to final blood draw at 4 weeks

• Change in Serum C-Reactive Protein (CRP) Concentration

  From enrollment to final blood draw at 4 weeks

Other Outcomes (2)

• Exploratory Change in Additional Serum Amino Acid Concentrations

  From enrollment to final blood draw at 4 weeks

• Exploratory Change in PBMC Gene Expression Profiles

  From enrollment to final blood draw at 4 weeks

Study Arms (3)

Animal → Plant → Plant+Leucine

EXPERIMENTAL

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.

Dietary Supplement: Animal-Based Protein Smoothie; Dietary Supplement: Plant-Based Protein Smoothie; Dietary Supplement: Plant-Based Protein Smoothie with Leucine

Plant-Based → Plant-Based with Leucine → Animal-Based

EXPERIMENTAL

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.

Dietary Supplement: Animal-Based Protein Smoothie; Dietary Supplement: Plant-Based Protein Smoothie; Dietary Supplement: Plant-Based Protein Smoothie with Leucine

Plant-Based with Leucine → Animal-Based → Plant-Based

EXPERIMENTAL

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.

Dietary Supplement: Animal-Based Protein Smoothie; Dietary Supplement: Plant-Based Protein Smoothie; Dietary Supplement: Plant-Based Protein Smoothie with Leucine

Interventions

Plant-Based Protein Smoothie DIETARY_SUPPLEMENT

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.

Animal → Plant → Plant+Leucine; Plant-Based with Leucine → Animal-Based → Plant-Based; Plant-Based → Plant-Based with Leucine → Animal-Based

Plant-Based Protein Smoothie with Leucine DIETARY_SUPPLEMENT

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.

Animal → Plant → Plant+Leucine; Plant-Based with Leucine → Animal-Based → Plant-Based; Plant-Based → Plant-Based with Leucine → Animal-Based

Animal-Based Protein Smoothie DIETARY_SUPPLEMENT

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.

Animal → Plant → Plant+Leucine; Plant-Based with Leucine → Animal-Based → Plant-Based; Plant-Based → Plant-Based with Leucine → Animal-Based

Eligibility Criteria

• Age: 18 Years - 65 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

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

You may not qualify if:

• History of cardiovascular disease, diabetes, or autoimmune disorders
• Active use of anti-inflammatory, immunomodulatory, or lipid-lowering medications
• Renal or hepatic dysfunction
• Pregnancy or breastfeeding
• 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
• Participation in another interventional study within the last 30 days

Sponsors & Collaborators

• University of Pittsburgh: lead

Study Sites (1)

UPMC Montefiore - Clinical and Translational Research Center (CTRC)

Pittsburgh, Pennsylvania, 15213, United States

RECRUITING

MeSH Terms

Conditions

Atherosclerosis

Interventions

Leucine

Condition Hierarchy (Ancestors)

Arteriosclerosis; Arterial Occlusive Diseases; Vascular Diseases; Cardiovascular Diseases

Intervention Hierarchy (Ancestors)

Amino Acids, Branched-Chain; Amino Acids; Amino Acids, Peptides, and Proteins; Amino Acids, Essential

Study Officials

• Babak Razani, MD-PhD

  University of Pittsburgh

  STUDY DIRECTOR

Central Study Contacts

Ali Ajam, MD

CONTACT

412-512-1044; ala449@pitt.edu

Babak Razani, MD-PhD

CONTACT

412-648-7496; brazani@pitt.edu

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: BASIC SCIENCE
• Intervention Model: CROSSOVER
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Postdoctoral Associate

Model Details: This is a randomized crossover study in which each participant receives all three interventions (animal protein smoothie, plant protein smoothie, plant protein smoothie with leucine) on separate study visits in a randomized order. This design allows within-subject comparisons of postprandial responses.

Study Record Dates

• First Submitted: July 16, 2025
• First Posted: August 13, 2025
• Study Start: March 24, 2026
• Primary Completion (Estimated): September 1, 2026
• Study Completion (Estimated): October 1, 2026
• Last Updated: March 25, 2026

Record last verified: 2026-03

Data Sharing

• IPD Sharing: Will not share

Locations

US (1)