Pea Protein vs. Milk Protein: Muscle Growth Showdown

clinical-trial PMID: 36170964

Quick Summary: New research shows that a blend of plant proteins, including pea protein, can build muscle just as well as milk protein in young men. This means you can get the same muscle-building benefits from a plant-based protein source!

Does Pea Protein Build Muscle?

Yes! This study found that a mix of plant proteins, including pea protein, is just as effective as milk protein for building muscle. Both groups of participants in the study saw similar increases in muscle protein synthesis.

What The Research Found

Researchers compared the effects of a plant-based protein blend to milk protein on muscle growth. They found:

Muscle Growth: Both milk protein and the plant-based blend (including pea protein) increased muscle protein synthesis (muscle building).

Amino Acids: Milk protein led to a greater increase in essential amino acids in the blood compared to the plant-based blend.

Overall: Despite the difference in amino acid levels, both protein sources resulted in similar muscle growth.

Study Details

Who was studied: 24 healthy young men.

How long: The study measured muscle growth over a 5-hour period after protein consumption.

What they took:

Group 1: 30 grams of milk protein.
Group 2: A blend of plant proteins: 15g wheat, 7.5g corn, and 7.5g pea protein.

What This Means For You

Plant-Based Option: If you're looking for a plant-based protein source, pea protein (when combined with other plant proteins) can be a great choice for building and maintaining muscle.

Muscle Building: You don't have to rely solely on animal-based protein to see results in the gym.

Variety is Key: This study used a blend of plant proteins. Consider a mix of different plant-based sources to ensure you're getting a complete amino acid profile.

Study Limitations

Specific Group: The study only included young men, so the results might be different for women, older adults, or people with health conditions.

Short Timeframe: The study only looked at muscle growth over a few hours. We don't know the long-term effects.

Blend Matters: The study used a specific blend of plant proteins. The results might be different with just pea protein alone.

No Performance Tests: The study measured muscle synthesis, not strength or muscle size.

Small Sample Size: The study had a relatively small number of participants, which could limit the findings.

Key Findings

This 2023 clinical trial found that a plant-derived protein blend (15g wheat, 7.5g corn, 7.5g pea protein) increased myofibrillar protein synthesis rates in healthy young males to a similar extent as 30g milk protein. Despite lower postprandial essential amino acid (EAA) availability in the plant-blend group, no statistically significant difference in muscle protein synthesis rates was observed between treatments (0.053 ± 0.013%/h for milk vs. 0.064 ± 0.016%/h for plant blend; P=0.08). The study concludes that combining plant proteins can overcome the anabolic limitations of individual sources, offering a viable alternative to animal protein for muscle maintenance.

Study Design

A randomized, double-blind, parallel-group clinical trial involving 24 healthy young males (mean age 24 ± 4 years). Participants received a primed continuous infusion of isotopically labeled phenylalanine to track muscle protein synthesis. Blood and muscle biopsies were collected over 5 hours post-protein ingestion to measure plasma amino acid profiles (secondary outcome) and myofibrillar protein synthesis rates (primary outcome). Data were analyzed using 2-factor repeated measures ANOVA and 2-sample t-tests.

Dosage & Administration

Both groups consumed 30g of protein:
- Milk protein (MILK): 30g of milk-derived protein.
- Plant blend (PLANT-BLEND): 15g wheat, 7.5g corn, and 7.5g pea protein combined.
Proteins were administered as a drink. The study did not specify timing relative to exercise or meal composition.

Results & Efficacy

Muscle protein synthesis: Both groups showed significant increases (P < 0.001), with no difference between treatments (MILK: 0.053 ± 0.013%/h; PLANT-BLEND: 0.064 ± 0.016%/h; P=0.08).
Plasma EAAs: Milk protein induced a greater rise in EAA concentrations over 5 hours (incremental AUC: 151 ± 31 vs. 79 ± 12 mmol·300 min·L⁻¹; P < 0.001), suggesting the plant blend was less bioavailable.
Amino acid deficiencies: The plant blend had lower leucine, lysine, and methionine content, aligning with prior research on plant protein limitations.

Limitations

Sample specificity: Only healthy young males were studied, limiting generalizability to women, older adults, or clinical populations.
Short duration: The 5-hour postprandial window may not capture long-term anabolic effects or differences in protein utilization.
Combined protein blend: Results reflect a specific mix of wheat, corn, and pea proteins; isolated pea protein’s efficacy remains untested.
No functional outcomes: The study measured synthesis rates but not strength, muscle mass, or performance changes.
Small sample size: 24 participants may reduce statistical power to detect subtle differences.

Clinical Relevance

For supplement users, this study demonstrates that a plant-based protein blend can stimulate muscle protein synthesis as effectively as milk protein in the short term. However, the blend’s composition (including wheat and corn) complicates attribution to pea protein alone. Practical applications include:
1. Plant-based alternatives: Combining complementary proteins may offset individual amino acid deficiencies, supporting muscle health.
2. Dosage considerations: 30g of the blend was sufficient to elicit an anabolic response, though higher doses might be needed for optimal EAA availability.
3. Target population: Findings apply to healthy young males; further research is required for other demographics.
4. Digestive factors: The study did not assess gastrointestinal tolerance, which may differ between plant and animal proteins.

This trial provides evidence that plant-derived blends can be anabolic but highlights the importance of amino acid balance and dosing. Users seeking plant-based options should prioritize blends with complementary amino acid profiles or consider fortification with limiting amino acids like leucine.

Source: PubMed | Clinical Trial ID: NTR6548