Randomized Crossover Trial of Protein Source and Leucine Supplementation on Metabolic and Immune Signaling Pathways
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 入组人数
- 20
- 试验地点
- 1
- 主要终点
- Change in Circulating Serum Leucine Concentration
研究概览
简要总结
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.
详细描述
This is a randomized, controlled, crossover clinical trial designed to investigate the acute effects of dietary protein source and leucine supplementation on circulating amino acids and downstream metabolic and immune signaling pathways in healthy adults. The study is being conducted by researchers at the University of Pittsburgh and is based on emerging evidence that dietary protein composition-particularly the type and amount of amino acids such as leucine-may influence key biological processes associated with cardiometabolic health.
Proteins are an essential part of the human diet, and different protein sources (plant vs. animal) contain varying amounts and types of amino acids. One amino acid of particular interest is leucine, a branched-chain amino acid (BCAA) known to activate the mTOR (mechanistic target of rapamycin) signaling pathway. The mTOR pathway plays a critical role in regulating cell growth, metabolism, immune responses, and energy use. Excessive or chronic activation of this pathway has been implicated in cardiometabolic diseases, including atherosclerosis, obesity, insulin resistance, and inflammation.
Animal-derived proteins such as milk or meat tend to be richer in leucine than plant-derived proteins like soy or pea protein. This difference may explain some of the metabolic disparities observed between diets high in animal protein versus plant protein. While plant-based diets are often recommended for their anti-inflammatory and cardiovascular benefits, they may lack sufficient leucine to activate anabolic signaling pathways in certain tissues. It remains unclear whether supplementing plant-based protein with free leucine can achieve the same biological responses as animal protein ingestion.
The trial includes three study arms: (1) a smoothie containing only plant-based protein, (2) a smoothie containing animal-based protein, and (3) a plant-based smoothie with added free leucine. Each smoothie is isocaloric and matched in macronutrient content, differing only in protein source and leucine content. All meals will be prepared and administered under controlled conditions at the Clinical and Translational Research Center (CTRC) at UPMC Montefiore.
Participants will be healthy adults without chronic illnesses or recent infections, aged 18 years and older. Each participant will complete all three study visits in a randomized order, with a minimum 3-day washout period between visits. At each visit, participants will be asked to fast for 10 hours overnight before arriving at the CTRC in the morning. Upon arrival, fasting blood will be collected, followed by consumption of the assigned test smoothie. Additional blood samples will be collected at 1 and 3 hours post-consumption to evaluate postprandial responses.
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Crossover
- 主要目的
- Basic Science
- 盲法
- None
入排标准
- 年龄范围
- 18 Years 至 65 Years（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 是
入选标准
- •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
排除标准
- •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
研究组 & 干预措施
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.
干预措施: Animal-Based Protein Smoothie (Dietary Supplement)
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.
干预措施: Plant-Based Protein Smoothie (Dietary Supplement)
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.
干预措施: Plant-Based Protein Smoothie with Leucine (Dietary Supplement)
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.
干预措施: Animal-Based Protein Smoothie (Dietary Supplement)
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.
干预措施: Plant-Based Protein Smoothie (Dietary Supplement)
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.
干预措施: Plant-Based Protein Smoothie with Leucine (Dietary Supplement)
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.
干预措施: Animal-Based Protein Smoothie (Dietary Supplement)
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.
干预措施: Plant-Based Protein Smoothie (Dietary Supplement)
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.
干预措施: Plant-Based Protein Smoothie with Leucine (Dietary Supplement)
结局指标
主要结局
Change in Circulating Serum Leucine Concentration
时间窗: From enrollment to final blood draw at 4 weeks
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)
次要结局
- 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)
研究者
Ali Ajam
Postdoctoral Associate
University of Pittsburgh