The multi-dimensional role of L-Arginine in elderly health

L-Arginine is a semi-essential amino acid. In the elderly, endogenous synthesis can meet basic requirements, but with advancing age, synthetic capacity declines, necessitating moderate supplementation through diet or supplements. Its role in elderly health revolves around four core dimensions: cardiovascular protection, immune regulation, muscle maintenance, and cognitive function support. Meanwhile, attention should be paid to appropriate dosage and safety in light of the physiological characteristics of the elderly, as detailed below:

I. Cardiovascular System Protection: Improving Blood Flow and Vascular Function

Aging is associated with decreased vascular elasticity and slowed blood flow, which can easily lead to hypertension, atherosclerosis, and other diseases. L-Arginine exerts protective effects through the following mechanisms:

Core Substrate for Nitric Oxide (NO) Synthesis: Under the action of nitric oxide synthase (NOS), L-Arginine is converted into NO, a key signaling molecule for vascular endothelial relaxation. NO dilates blood vessels, reduces peripheral resistance, and helps regulate blood pressure—particularly exerting a positive effect on diastolic blood pressure in elderly hypertensive patients. Additionally, NO inhibits platelet aggregation and vascular smooth muscle cell proliferation, slowing the formation and progression of atherosclerotic plaques.

Enhancing Microcirculation and Tissue Oxygen Supply: Elderly individuals often experience peripheral circulatory disorders (e.g., cold hands and feet). By promoting NO production, L-Arginine dilates microvessels, improves blood perfusion in the limbs, heart, and brain, and alleviates symptoms such as fatigue and chest tightness caused by hypoxia.

Regulating Lipid Metabolism: Moderate L-Arginine supplementation can lower total cholesterol and triglyceride levels in the elderly, increase high-density lipoprotein cholesterol (HDL-C) content, reduce lipid deposition on vascular walls, and decrease the risk of cardiovascular events.

II. Immune Function Regulation: Strengthening Resistance in the Elderly

Age-related decline in immune organ function and immune cell activity increases susceptibility to bacterial and viral infections in the elderly. The immunomodulatory effects of L-Arginine are reflected in:

Promoting Immune Cell Proliferation and Activation: L-Arginine serves as an important nutritional substrate for lymphocytes and macrophages. It enhances the proliferative capacity of T lymphocytes and the secretion of cytokines (e.g., IL-2, IFN-γ), boosts the phagocytic and cytotoxic functions of macrophages, and strengthens the body's defense against pathogens.

Improving Intestinal Immune Barrier: Intestinal mucosal atrophy and impaired barrier function in the elderly are prone to intestinal flora imbalance and endotoxin leakage. L-Arginine promotes the proliferation and repair of intestinal mucosal cells, enhances the expression of intestinal tight junction proteins, reduces systemic inflammation caused by endotoxin entry into the bloodstream, and indirectly improves overall immune function.

III. Muscle Mass Maintenance and Anti-Sarcopenia: Alleviating Sarcopenia in the Elderly

Sarcopenia is a common condition in the elderly, characterized by decreased muscle mass and strength. L-Arginine delays the progression of sarcopenia through multiple pathways:

Activating the mTOR Signaling Pathway: L-Arginine activates the mammalian target of rapamycin (mTOR) pathway, promoting muscle protein synthesis while inhibiting muscle protein breakdown, thus reducing muscle loss caused by aging or insufficient physical activity.

Synergizing with Growth Hormone Secretion: L-Arginine stimulates the pituitary gland to secrete growth hormone, which further promotes muscle cell proliferation and skeletal muscle development. When combined with exercise, the effect of increasing muscle mass is more pronounced.

Enhancing Exercise Endurance: L-Arginine supplementation improves energy metabolism in the elderly, reduces lactic acid accumulation during exercise, alleviates post-exercise muscle soreness, helps the elderly maintain moderate physical activity, and forms a positive cycle of "exercise-muscle protection".

IV. Cognitive Function Support: Improving Cerebral Blood Flow and Neuroprotection

Reduced cerebral blood flow and declining neuronal function in the elderly often lead to memory loss and cognitive impairment. The roles of L-Arginine include:

Dilating Cerebral Blood Vessels and Enhancing Cerebral Perfusion: By generating NO to dilate cerebral blood vessels, L-Arginine increases oxygen and nutrient supply to brain tissue, improves cognitive sluggishness caused by cerebral ischemia, and exerts an auxiliary improvement effect in elderly individuals with mild cognitive impairment.

Inhibiting Neuroinflammation: Chronic inflammatory responses are common in the aging brain. L-Arginine reduces neuronal damage caused by inflammatory factors by regulating immune cytokine secretion, while promoting the expression of neurotrophic factors to protect the structure and function of neurons.

V. Other Auxiliary Effects

Promoting Wound Healing: The elderly have impaired skin healing ability. L-Arginine accelerates collagen synthesis and fibroblast proliferation, helping elderly patients with postoperative or skin injuries speed up wound repair.

Regulating Glucose Metabolism: Some studies indicate that L-Arginine can improve insulin sensitivity and promote glucose uptake, exerting a certain auxiliary effect on blood glucose control in elderly patients with type 2 diabetes. However, it should be used cautiously in combination with hypoglycemic drugs.

VI. Safety and Precautions

Appropriate Dosage: The recommended daily supplementation dosage for the elderly is 1–3 g. Excessive supplementation (>5 g/d) may cause gastrointestinal discomfort (e.g., nausea, diarrhea) or headaches and hypotension due to excessive NO production.

Contraindicated Populations

Patients with Severe Hepatic or Renal Insufficiency: Metabolites of L-Arginine are excreted through the liver and kidneys. Impaired liver or kidney function can lead to metabolite accumulation and hyperammonemia.

Elderly Individuals Taking Anticoagulants (e.g., warfarin) or Antihypertensive Drugs: L-Arginine may synergize with these medications to enhance anticoagulant and hypotensive effects, increasing the risk of bleeding or hypotension. Consult a physician before use.

Patients with Herpes Virus Infections: L-Arginine may promote viral replication and exacerbate infection symptoms.

Supplementation Methods: Priority should be given to dietary intake (e.g., lean meat, fish, nuts, legumes). Supplements should be considered only when dietary intake is insufficient, and should be balanced with other amino acids (e.g., L-Lysine) to avoid excessive intake of a single amino acid.

L-Arginine exerts multi-dimensional positive effects on elderly health, but it is essential to follow the principle of "moderate supplementation and individual adaptation", and use it rationally in combination with the underlying diseases and physical conditions of the elderly to maximize its health benefits.