Plant-Based Protein for Healthy Nutrition

(PBP Trial)

Not currently recruiting at 1 trial location

Overseen By Changhyun Lim, PhD

Age: 18 - 65

Sex: Any

Trial Phase: Academic

Sponsor: McMaster University

Must not be taking: Analgesics, Anti-inflammatories, Corticosteroids, others

Disqualifiers: Neuromuscular problems, Metabolic disorders, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Compensation: Varies

Number of Visits: 2

Duration: 1 day

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial examines how a new plant-based protein blend affects muscle growth compared to whey protein, known for its muscle-building benefits. The study will test three protein options: whey protein, a plant-based protein, and a plant-based protein enriched with leucine, an amino acid important for muscle building. Individuals who maintain a healthy weight, do not smoke, and avoid certain medications may be suitable for this study. Participants should be in good health and free from ongoing illnesses. As an unphased trial, this study offers a unique opportunity to contribute to groundbreaking research on plant-based nutrition and muscle growth.

Will I have to stop taking my current medications?

The trial requires that you are not currently using analgesic or anti-inflammatory drugs, corticosteroids, hormonal contraceptives, or anabolic steroids. If you are taking any of these, you would need to stop before participating.

Is there any evidence suggesting that this trial's treatments are likely to be safe?

Research has shown that whey protein isolate is generally safe, though it can cause side effects. Users have reported more frequent bowel movements, acne, nausea, thirst, and bloating. Concerns exist about potential liver and kidney issues, but these typically occur with very high doses.

For plant-based protein isolate, studies indicate a higher risk of heavy metals like lead, which can be concerning if consumed in large amounts over time. Some individuals might also experience digestive problems.

The blend of plant-based protein with added leucine appears as safe as regular plant-based protein. However, adding leucine might cause stomach issues like gas or nausea.

Overall, these proteins are usually well-tolerated, but awareness of potential side effects, especially with long-term use, is important. ^{1 2 3 4 5}

Why are researchers excited about this trial's treatments?

Researchers are excited about these treatments because they explore how plant-based proteins stack up against the well-known whey protein in supporting muscle growth. Typically, whey protein, rich in essential amino acids like leucine, is considered the gold standard for muscle protein synthesis. However, this trial investigates if enriching plant-based protein with leucine can mimic or match the muscle-building effects of whey. This approach could offer a viable alternative for those seeking a plant-based diet without compromising on muscle development. By potentially improving the quality of plant-based proteins, this research could broaden options for athletes and fitness enthusiasts looking for effective, sustainable nutrition.

What evidence suggests that this trial's treatments could be effective for muscle building?

Studies have shown that whey protein isolate, a treatment in this trial, effectively builds muscle. It increases muscle size and strength while reducing body fat. Another treatment arm in this trial will evaluate plant-based protein isolates, which research indicates are less effective than whey protein for muscle growth. However, a separate treatment arm will test plant-based proteins enriched with leucine, an amino acid that aids muscle building. Adding leucine can enhance the effectiveness of plant-based proteins, potentially supporting muscle growth similar to whey. ^{6 7 8 9 10}

Who Is on the Research Team?

Stuart Phillips, PhD

Principal Investigator

McMaster University

Are You a Good Fit for This Trial?

This trial is for healthy non-smokers aged 18-30 with a BMI of 18-30 kg/m2. Participants must have regular menstrual cycles without hormonal contraceptives if female, and be in good health as confirmed by a questionnaire. Those using steroids, analgesics, anti-inflammatories or corticosteroids, or with chronic illness or muscle diseases cannot join.

Inclusion Criteria

Be in general good health as assessed by a general health questionnaire

Have a body mass index (BMI) between 18-30 kg·m2 (inclusive)

Regular menstrual cycle and not using hormonal contraceptives

Exclusion Criteria

I am currently taking painkillers or anti-inflammatory medication.

I have a long-term health condition or a recent illness.

I have a history of muscle or bone diseases.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

1-2 weeks

Treatment

Participants consume test drinks containing either whey protein isolate, plant-based protein isolate, or plant-based protein isolate with leucine to assess muscle protein synthesis and other responses.

1 day

1 visit (in-person)

Follow-up

Participants are monitored for safety and effectiveness after treatment, including assessments of muscle protein synthesis, aminoacidemia, and tolerability.

5 hours

1 visit (in-person)

What Are the Treatments Tested in This Trial?

Interventions

• Protein Quality

Trial Overview The study is testing how well a new plant-based protein blend helps build muscle compared to whey protein isolate. It's designed to see if the plant protein can match the muscle-building response that whey protein typically produces.

How Is the Trial Designed?

Group I: Whey protein isolate Experimental Treatment 1 Intervention

Whey protein isolate is the 'gold standard' of protein supplements due to being rich in essential amino acids and leucine. Leucine is a key amino acid the is required to stimulate muscle protein synthesis. Muscle protein synthesis is the major mechanism the underpins muscle growth. The whey protein would ostensibly serve as a positive control.

Group II: Plant based protein isolate + leucine Experimental Treatment 1 Intervention

Enriching plant-based protein with leucine will increase the 'quality' of said protein source and theoretically should have similar muscle protein synthetic responses to whey protein.

Group III: Plant based protein isolate Experimental Treatment 1 Intervention

Current plant-based protein isolates available contain insufficient amounts of leucine, and are less digestible, resulting in a reduced muscle protein synthesis responses. The plant based protein would ostensibly serve as a negative control.

Who Is Running the Clinical Trial?

McMaster University

Lead Sponsor

Trials

936

Recruited

2,630,000+

Citations

1. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/38846451/

Muscle Protein Synthesis in Response to Plant-Based ... Results: All protein supplements increased mixed MPS above postabsorptive levels (P < 0.001). However, MPS increase following ingestion of PBP ...

2. sciencedirect.com sciencedirect.com/science/article/pii/S2475299124017037

Muscle Protein Synthesis in Response to Plant-Based ... For example, ingestion of plant-based protein results in a lower anabolic response compared with ingestion of isonitrogenous animal-source proteins in young and ...

3. clinicaltrials.gov clinicaltrials.gov/study/NCT05020808

The Effect of a Plant Protein Isolate on Muscle ... Plant-based proteins contain several amino acids that are essential to signal growth, reconditioning, maintenance and preservation of skeletal muscle mass. This ...

4. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC10687132/

Effect of Soy Protein Supplementation on Muscle ... This systematic review evaluates the evidence from randomised controlled clinical trials of the effects of SP supplementation in active individuals and athletes

5. mdpi.com mdpi.com/2072-6643/17/15/2571

Effect of Plant-Based Proteins on Recovery from ... While plant protein blends demonstrate promising outcomes, studies using isolated sources often show limited improvements in fatigue resistance, muscle soreness ...

6. health.harvard.edu health.harvard.edu/staying-healthy/the-hidden-dangers-of-protein-powders

The hidden dangers of protein powders - Harvard Health "There are limited data on the possible side effects of high protein intake from supplements," McManus says. It may cause digestive distress. " ...

7. consumerreports.org consumerreports.org/lead/protein-powders-and-shakes-contain-high-levels-of-lead-a4206364640/

Protein Powders and Shakes Contain High Levels of Lead Nearly all the plant-based products CR tested had elevated lead levels, but some were particularly concerning. Two had so much lead that CR's ...

8. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC7509468/

A human health risk assessment of heavy metal ingestion ... Plant based protein powder supplements tend to have a higher heavy metal burden than animal-based protein powder supplements. •. Exposure to As, Cd, Hg, and Pb ...

9. cleanlabelproject.org cleanlabelproject.org/wp-content/uploads/CleanLabelProject_ProteinStudyWhitepaper_010625.pdf

2024-25 Protein Powder Category Report Plant-based protein powders were the most contaminated, containing five times more cadmium than their whey-based counterparts. Even the flavor of protein ...

10. npr.org npr.org/2025/10/16/nx-s1-5576294/protein-powder-lead-consumer-reports

Consumer Reports finds lead in popular protein powders Consumer Reports expressed concern about high levels of lead in some two dozen protein powders, but only with repeated high exposure.