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

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

Interventions

DIETARY_SUPPLEMENT

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.

DIETARY_SUPPLEMENT

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.

DIETARY_SUPPLEMENT

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.

Sponsors & Collaborators

• University of Pittsburgh

  lead OTHER

Principal Investigators

• Babak Razani, MD-PhD · University of Pittsburgh

Study Design

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

NONE

Model

CROSSOVER

Eligibility

Min Age

18 Years

Max Age

65 Years

Sex

ALL

Healthy Volunteers

Yes

Timeline & Regulatory

Start

2026-03-24

Primary Completion

2026-09-30

Completion

2026-10-31

Countries

• United States

Study Locations