Plant Peptides
Also known as: Plant-derived peptides, Plant protein hydrolysates, Bioactive plant peptides, Plant Peptides
Overview
Plant peptides are short chains of amino acids derived from plant proteins through enzymatic hydrolysis. They are concentrated and isolated from various plant sources such as soy, rice, pea, oat, and potato proteins for use as supplements. These bioactive compounds are primarily utilized to support muscle mass and strength, enhance cardiovascular health, and regulate metabolic processes. They are increasingly incorporated into sports nutrition products and functional foods due to their beneficial properties. Key characteristics include antioxidant, antihypertensive, and lipid-lowering effects, alongside their ability to stimulate muscle protein synthesis. While research is emerging, several systematic reviews and randomized controlled trials (RCTs) support their efficacy, particularly when compared to animal proteins. The evidence quality is moderate, with ongoing research to further delineate their specific benefits and mechanisms.
Benefits
Plant peptides offer several evidence-based benefits. For muscle mass and strength, they support gains during resistance training, though studies indicate slightly lower efficacy compared to animal proteins (Standardized Mean Difference ~ -0.20 for muscle mass, p=0.02), with no significant difference in muscle strength or physical performance. This suggests they are a viable option for muscle support, especially for those preferring plant-based sources. In terms of cardiovascular health, substituting animal protein with plant peptides/proteins has been shown to reduce LDL cholesterol and other cardiovascular risk markers in adults, including those with hyperlipidemia. Beyond these primary effects, plant peptides also exhibit potential antioxidant and anti-inflammatory properties, and can contribute to improved metabolic profiles. Older adults may experience smaller differences in muscle mass gains compared to younger adults when using plant peptides, making them a relevant option for this demographic. The effects on muscle mass are statistically significant but small, while cardiovascular lipid reductions are clinically relevant, though varying by peptide source and study. Muscle mass studies typically range from 3 to 15 weeks, while cardiovascular effects are observed over several weeks to months.
How it works
Plant peptides exert their effects primarily by supplying essential amino acids necessary for muscle protein synthesis, thereby supporting muscle growth and repair. Beyond this, they modulate enzymes involved in lipid metabolism and blood pressure regulation. Specifically, some plant peptides may inhibit angiotensin-converting enzyme (ACE), contributing to antihypertensive effects, and can influence LDL receptor pathways to help lower cholesterol levels. These peptides interact with the musculoskeletal system by promoting anabolic signaling and with the cardiovascular system by modulating lipid profiles and blood pressure. Due to enzymatic hydrolysis, plant peptides generally have improved absorption and bioavailability compared to intact proteins, with their efficacy depending on their specific size and amino acid sequence.
Side effects
Plant peptides are generally considered safe, with no major adverse effects consistently reported in randomized controlled trials. The most common side effect, though rare, is mild gastrointestinal discomfort, which may occur in some individuals. Uncommon side effects (1-5% frequency) have not been consistently reported. Very rare side effects (<1% frequency) include the possibility of allergic reactions in individuals sensitive to the source plants (e.g., soy, pea). Limited evidence suggests that soy peptides might interfere with levothyroxine absorption in hypothyroid patients, necessitating caution in this population. Contraindications are primarily limited to individuals with known allergies to the specific plant sources from which the peptides are derived. Apart from the caution for hypothyroid patients on thyroid medication, plant peptides are generally safe for consumption by healthy adults.
Dosage
While there is no universally established minimum effective dose for all plant peptides, studies on similar compounds like collagen peptides have used 5-15 g/day. For plant peptides, dosing often aligns with general protein intake recommendations, typically around 20-30 g of protein per serving. For muscle support, an optimal dosage range is generally considered to be 15-30 g of plant protein hydrolysate per day, especially when combined with resistance training. There is no established maximum safe dose, with doses up to 30 g/day being well tolerated in studies. Timing considerations suggest that post-exercise ingestion may optimize muscle protein synthesis. Hydrolyzed forms of plant peptides are preferred due to their enhanced absorption and bioavailability. Enzymatic hydrolysis is crucial for improving their absorption. While vitamin C is known to enhance the effects of collagen peptides, its role as a required cofactor for plant peptides is less clear.
FAQs
Are plant peptides as effective as animal peptides for muscle growth?
Plant peptides are slightly less effective for muscle mass gains compared to animal proteins but show comparable efficacy for muscle strength and overall physical performance.
Can plant peptides improve cardiovascular health?
Yes, evidence supports that plant peptides can reduce LDL cholesterol and other cardiovascular risk markers, contributing to improved heart health.
Are plant peptides safe?
Generally, plant peptides are safe with minimal side effects. However, individuals with allergies to specific plant sources or those on thyroid medication should exercise caution.
When should I take plant peptides?
For optimal muscle benefits, taking plant peptides post-exercise is generally recommended to support muscle protein synthesis.
Do all plant peptides have the same effects?
No, the effects of plant peptides can vary significantly depending on their source (e.g., soy, rice, pea) and their specific amino acid profile.
Research Sources
- https://www.germanjournalsportsmedicine.com/archive/archive-2024/issue-5/collagen-peptide-supplementation-and-musculoskeletal-performance-a-systematic-review-and-meta-analysis/ – This systematic review and meta-analysis of 13 RCTs found that hydrolyzed collagen peptides, mostly at 15g daily doses, improved musculoskeletal performance parameters in healthy adults. While focused on collagen, it provides insights into peptide supplementation's impact on musculoskeletal health, highlighting the potential for similar benefits from other hydrolyzed peptides.
- https://academic.oup.com/nutritionreviews/article/83/7/e1581/7954494 – This systematic review and meta-analysis of 30 RCTs concluded that plant proteins yield slightly lower muscle mass gains (SMD -0.20) than animal proteins in adults, but showed no significant difference in muscle strength. The study highlights the heterogeneity in plant protein types and the need for more research on sarcopenia outcomes.
- https://pmc.ncbi.nlm.nih.gov/articles/PMC7760812/ – This comprehensive systematic review and meta-analysis of 112 RCTs demonstrated that substituting animal protein with plant protein reduces LDL cholesterol and other cardiovascular risk markers. The review noted that soy protein was dominant in the studies, suggesting a need for more diverse plant protein research and acknowledging potential confounding from other bioactive compounds in soy.
Supplements Containing Plant Peptides
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