The nutritional support value of L-leucine in wound healing

Through its core functions of "promoting protein synthesis + regulating repair signals + enhancing immune function," L-leucine provides critical nutritional support for wound healing. It accelerates wound closure and improves healing quality, making it an important nutritional supplement during trauma repair.

I. Core Nutritional Support Mechanisms

1. Driving Protein Synthesis at the Wound Site

L-leucine is a key activator of the mammalian target of rapamycin (mTOR) signaling pathway, directly binding to the mTOR complex to initiate the expression of ribosomal protein synthesis-related genes. After trauma, it promotes protein synthesis in fibroblasts and keratinocytes around the wound, accelerating the production of repair matrices such as collagen and elastin. This increases the growth rate of wound granulation tissue by 30%–40% and shortens the healing cycle.Additionally, L-leucine improves muscle protein synthesis efficiency, reduces trauma-induced muscle breakdown, and maintains body nitrogen balance. It provides sufficient amino acid raw materials for wound repair, avoiding delayed healing caused by malnutrition.

2. Regulating Wound Repair Signaling Pathways

Promoting Growth Factor Secretion: L-leucine induces the expression of platelet-derived growth factor (PDGF), transforming growth factor-β (TGF-β), and vascular endothelial growth factor (VEGF). These factors accelerate fibroblast proliferation and angiogenesis, improve wound blood circulation and nutrient supply, and enhance tissue repair capacity.

Inhibiting Excessive Inflammatory Activation: In the early post-traumatic stage, L-leucine regulates the nuclear factor-κB (NF-κB) signaling pathway to inhibit the excessive release of pro-inflammatory factors (IL-6, TNF-α), reducing wound inflammation and edema. In the later stage, it promotes the secretion of anti-inflammatory factors (IL-10), creating a suitable microenvironment for tissue repair.

3. Enhancing Immune Function and Stress Resistance

Trauma impairs immune function. L-leucine promotes the proliferation and activation of T lymphocytes and B lymphocytes, enhances macrophage phagocytic capacity and cytokine secretion efficiency, and strengthens the body’s resistance to wound infections, reducing the risk of post-traumatic infection.Furthermore, it increases the activity of antioxidant enzymes (SOD, CAT), reduces damage to repair cells caused by reactive oxygen species (ROS) produced during trauma stress, and regulates glucocorticoid levels to alleviate the inhibitory effect of stress responses on wound healing.

II. Application Value for Different Trauma Types

1. Surgical Trauma

Postoperative supplementation of L-leucine (10–20 g/day) significantly accelerates surgical wound healing and reduces the incidence of complications such as incision infection and dehiscence. It is particularly suitable for high-trauma scenarios such as abdominal surgery and orthopedic surgery. Additionally, it mitigates postoperative muscle loss, accelerates physical recovery, and shortens hospital stays.

2. Burn and Scald Wounds

Burn patients experience a hypermetabolic, high-consumption state. L-leucine enhances protein synthesis and immune regulation to accelerate the epithelialization of burn wounds and reduce excessive scar tissue proliferation. Synergistic supplementation with glutamine and arginine further improves wound healing quality and reduces the risk of infection and metabolic disorders.

3. Chronic Wounds (Pressure Ulcers, Diabetic Foot)

Patients with chronic wounds often suffer from malnutrition and metabolic disorders. L-leucine improves the local microenvironment of wounds, restores fibroblast activity, enhances angiogenesis, and helps initiate the repair process of long-term unhealed wounds. It also regulates glucose metabolism (especially suitable for diabetic foot patients), reducing the inhibitory effect of hyperglycemia on wound healing.

III. Application Optimization and Precautions

1. Supplementation Dosage and Methods

Recommended Dosage: 15–20 g/day during the acute trauma phase (1–7 days), and 10–15 g/day during the recovery phase (8–30 days). Administer in 2–3 divided doses to avoid metabolic burden from single excessive intake.

Supplementation Methods: Can be taken orally as a pure L-leucine preparation or as a complex amino acid nutritional supplement containing L-leucine. Taking with food improves absorption efficiency.

2. Synergistic Supplementation Effects

Combined supplementation with glutamine (promotes intestinal barrier function), vitamin C (promotes collagen synthesis), and zinc (enhances enzyme activity and immune function) improves nutritional support effects by 40%–50%, more comprehensively meeting the nutritional needs of wound healing.

3. Adaptation for Special Populations

Patients with Hepatic or Renal Insufficiency: Appropriately reduce the dosage (≤10 g/day) to avoid accumulation of amino acid metabolites.

Diabetic Patients: Prioritize sugar-free preparations and monitor blood glucose changes during supplementation to avoid affecting blood glucose control.

Children and the Elderly: Adjust dosage based on body weight (children: 0.2–0.3 g/kg/day; elderly: 10–15 g/day) to ensure safety and tolerance.

IV. Common Problems and Solutions

Poor Healing Effect: Check if the supplementation dosage is sufficient; appropriately increase the dosage or combine with complex nutritional supplements. Simultaneously investigate other influencing factors such as wound infection and abnormal blood glucose.

Gastrointestinal Discomfort (Bloating, Diarrhea): Reduce the single dosage, switch to small, frequent supplementation, or take with meals to minimize gastrointestinal irritation.

Concerns About Metabolic Burden: Short-term supplementation (≤30 days) at the recommended dosage poses no significant metabolic risks for healthy individuals; long-term supplementation requires regular monitoring of liver and kidney function.