Health TrialsbyHealthPanel

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

ConditionCardiometabolic Health
Trial statusRecruiting
Trial phaseNot applicable
Trial typeInterventional
Biological sexAll
Age18-65
SponsorUniversity of Pittsburgh

About this trial

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.

Eligibility criteria

This trial accepts healthy volunteers

Qualifiers

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

Disqualifiers

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

Trial design

Design model

Crossover

Treatments tested in this trial

  • 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.

  • 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.

  • 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.

Treatment groups

20 Participants
are divided into 3 treatment groups
Group A: Animal → Plant → Plant+LeucineExperimental treatment 3 interventions
Group B: Plant-Based → Plant-Based with Leucine → Animal-BasedExperimental treatment 3 interventions
Group C: Plant-Based with Leucine → Animal-Based → Plant-BasedExperimental treatment 3 interventions

Trial outcomes

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)

Time frame
From enrollment to final blood draw at 4 weeks

Secondary outcomes

1

Change in Monocyte mTORC1 Signaling Activity

This outcome measures the change in mTORC1 signaling activity in peripheral blood mononuclear cells (PBMCs) from fasting to 1 and 3 hours after meal ingestion. mTORC1 activation will be quantified by assessing phosphorylation of S6 kinase (pS6K) using flow cytometry and/or Western blotting. Results will be compared within participants across the three dietary interventions-animal-based protein, plant-based protein, and plant-based protein supplemented with leucine-to determine the effect of protein source and leucine content on monocyte nutrient sensing. Unit of Measure: Relative band intensity (Western blot) or % pS6+ cells (flow cytometry)

Time frame
From enrollment to final blood draw at 4 weeks
2

Change in Serum IL-6 Concentration

Serum IL-6 concentration will be measured using ELISA to evaluate the inflammatory response to different protein sources and leucine supplementation. Unit of Measure: pg/mL

Time frame
From enrollment to final blood draw at 4 weeks
3

Change in Serum TNF-α Concentration

Serum TNF-α concentration will be measured using ELISA to evaluate the inflammatory response to different protein sources and leucine supplementation. Unit of Measure: pg/ml

Time frame
From enrollment to final blood draw at 4 weeks
4

Change in Serum C-Reactive Protein (CRP) Concentration

Serum CRP concentration will be measured using ELISA to evaluate the inflammatory response to different protein sources and leucine supplementation. Unit of Measure: mg/L

Time frame
From enrollment to final blood draw at 4 weeks

Other outcomes

1

Exploratory Change in Additional Serum Amino Acid Concentrations

If budget and sample quality allow, additional serum amino acids beyond leucine will be measured using targeted mass spectrometry to evaluate broader metabolic responses to dietary protein source and leucine supplementation. Unit of Measure: μmol/L

Time frame
From enrollment to final blood draw at 4 weeks
2

Exploratory Change in PBMC Gene Expression Profiles

If resources permit, transcriptomic profiling of peripheral blood mononuclear cells (PBMCs) will be performed to assess dietary protein-induced changes in expression of metabolic and inflammatory gene pathways. Unit of Measure: log₂ fold change

Time frame
From enrollment to final blood draw at 4 weeks

Sponsors and contacts

Click on the lead sponsor to view all of their trials.

University of Pittsburgh

Lead sponsor

Source ClinicalTrials.gov
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