The physiological functions and nutritional applications of phospholipids

I. Physiological Functions of Phospholipids: The Fundamental "Architect" of Life Activities

Phospholipids are a class of lipid compounds containing phosphate groups, widely present in animal and plant cells. Their physiological functions can be summarized into the following core aspects:

Structural Cornerstone of Cell Membranes

Phospholipids form the basic skeleton of cell membranes in the form of a bilayer, with hydrophilic phosphate heads outward and hydrophobic fatty acid tails inward, creating a barrier with fluidity and selective permeability. This structure not only maintains cell morphology but also participates in material transport (such as transmembrane transport of ions and nutrients) and signal transduction (such as anchoring and activation of receptor proteins). For example, lecithin (phosphatidylcholine) is the most abundant phospholipid in cell membranes, and its content directly affects membrane elasticity and cell viability. Especially in nerve cells, myelin sheaths composed of phospholipids accelerate nerve impulse conduction.

"Regulatory Hub" of Lipid Metabolism

As components of lipoproteins, phospholipids participate in the transport and metabolism of lipids in the blood. For instance, phospholipids in high-density lipoprotein (HDL) can bind cholesterol and transport it to the liver for metabolism, reducing the deposition of low-density lipoprotein (LDL) in the blood, thus regulating blood lipid levels. Additionally, phospholipids emulsify fats in the intestine, promoting the action of lipases and enhancing the absorption efficiency of fats and fat-soluble vitamins (such as A, D, E, K).

Nutritional "Guardian" of the Nervous System

Phospholipids account for approximately 25% of the dry weight of the brain, among which cephalin (phosphatidylethanolamine) and lecithin are important components of nerve cell synapse structures. Phosphatidylserine (PS), a special phospholipid, directly participates in the synthesis and release of neurotransmitters (such as acetylcholine), improves neural signal transmission, and protects memory and cognitive functions. Studies have shown that PS supplementation can delay cognitive decline in the elderly and alleviate stress-induced neural fatigue.

Antioxidant and Cellular Protection

Some phospholipids (such as phosphatidylcholine) have antioxidant properties, which can reduce oxidative stress damage to cells by scavenging free radicals or stabilizing cell membrane structures. For example, in the liver, phospholipids protect hepatocytes from toxins such as alcohol and drugs, and promote liver cell membrane repair, which is the basis for the action of phospholipid-based liver-protecting drugs.

Immune and Inflammatory Regulation

Phospholipids are involved in the activation and signal transduction of immune cells. For instance, phospholipid molecules on the surface of T cells can recognize antigens and initiate immune responses. Furthermore, phospholipid metabolites (such as arachidonic acid), as precursors of inflammatory mediators, have a metabolic balance that affects the intensity of inflammatory responses. Supplementing specific phospholipids (such as DHA phospholipids) can reduce chronic inflammation (such as arthritis and enteritis) by regulating the cyclooxygenase and lipoxygenase pathways.

II. Applications of Phospholipids in Nutritional Health Products: From Functional Targeting to Product Innovation

Based on the physiological activities of phospholipids, their applications in the health product sector show a diversified trend, mainly including the following directions:

Cardiovascular Health Intervention

Lecithin products: Using soybean lecithin or egg yolk lecithin as raw materials, 制成 (made into) soft capsules or powders, which promote lipoprotein synthesis and accelerate the metabolism of triglycerides and cholesterol in the blood by supplementing phosphatidylcholine. Clinical studies have shown that daily supplementation of 1-3g of lecithin can reduce serum triglyceride levels by 10%-15%, suitable for people with hyperlipidemia.

Compound formulations: Some products combine lecithin with fish oil (rich in Omega-3 fatty acids), using the emulsifying properties of phospholipids to enhance the absorption of fish oil and synergistically regulate blood lipids and vascular elasticity. For example, "phospholipid + EPA/DHA" preparations have become common health products for preventing arteriosclerosis.

Brain Health and Cognitive Improvement

Phosphatidylserine (PS) preparations: PS extracted from natural soybeans or fish is currently recognized as a "brain nutrient", often used to improve memory and alleviate brain fatigue. For example, PS health products for middle-aged and elderly people, with a daily supplement of 100-300mg, can significantly improve cognitive test scores, especially for mild cognitive impairment (MCI).

Lecithin + Choline combination: Choline is a precursor of acetylcholine, and combined supplementation with lecithin can enhance neurotransmitter synthesis, suitable for students and brain workers to prevent "brain fatigue". Related products often feature "brain health and intelligence enhancement", such as compound tablets of "phosphatidylcholine + B vitamins".

Liver Protection and Repair

Polyene phosphatidylcholine (PPC) products: High-purity PPC extracted from soybeans is a commonly used ingredient in clinical liver-protecting drugs, which can directly participate in liver cell membrane repair and promote hepatocyte regeneration. Capsules or tablets with PPC as the main component in health products are suitable for daily conditioning of patients with alcoholic liver injury and non-alcoholic fatty liver, with a recommended daily dose of 500-1000mg.

Plant phospholipid compound preparations: Some products combine phospholipids with milk thistle extract (containing silymarin), using the membrane repair function of phospholipids and the antioxidant effect of silymarin to enhance liver protection, suitable for daily protection of people who stay up late or attend social events.

Sports Nutrition and Muscle Health

Phosphatidylinositol (PI) supplements: PI is involved in signal transduction in muscle cells (such as insulin receptor signals), which can promote glucose uptake and muscle glycogen synthesis, suitable for athletes or fitness enthusiasts to accelerate post-exercise recovery. Some sports nutrition brands have launched "PI + branched-chain amino acids" compound powders, claiming to improve muscle synthesis efficiency.

Application of phospholipid emulsification technology: Using the emulsifying property of phospholipids, insoluble nutrients (such as coenzyme Q10 and curcumin) are encapsulated into nanoscale particles to make oral liquids or soft capsules, improving their bioavailability. For example, "phospholipid-encapsulated coenzyme Q10" products can increase the absorption rate by 3-5 times.

Nutritional Support for Special Populations

Addition to infant formula milk powder: Breast milk is rich in phospholipids (such as lecithin and sphingomyelin), which are crucial for infant brain and vision development. Currently, high-end infant formula milk powders commonly add plant-derived phospholipids (such as soybean lecithin) to simulate the lipid structure of breast milk and promote nutrient absorption.

Middle-aged and elderly joint health: Phospholipids are compounded with glucosamine and chondroitin to reduce joint inflammatory responses by regulating lipid metabolism in joint synovial fluid. Some health products use the formula of "phospholipid + chondroitin sulfate" to relieve osteoarthritis symptoms.

III. Application Challenges and Future Trends

Although phospholipids are widely used in health products, their stability (prone to oxidation) and source safety (such as the genetically modified controversy of soybean phospholipids) still need attention. Future research and development directions may focus on:

High-purity phospholipid extraction technologies: Such as supercritical CO₂ extraction and membrane separation technology, to improve the purity and biological activity of specific phospholipids (such as PS and PPC).

Targeted delivery systems: Using phospholipids to prepare liposomes to precisely deliver active ingredients to specific tissues (such as the brain and liver), enhancing efficacy and reducing dosage.

Innovation in natural sources: Developing non-soybean sources of phospholipids (such as algae and egg yolk phospholipids) to meet the needs of vegetarians and allergic populations.

With their diverse physiological functions, phospholipids are upgrading from traditional nutritional supplements to precise functional products, becoming an important bridge connecting basic nutrition and health management.