Myelin sheaths

Myelin sheaths — are specialized structures that surround the axons of nerve cells and ensure the rapid and accurate transmission of nerve impulses. They are composed predominantly of lipids (about 70–80%) and proteins, which makes them dense and gives them a characteristic white color.

Thanks to myelin, signal transmission in the nervous system becomes significantly more efficient, and energy costs are reduced.

Structure of Myelin Sheaths

Myelin is formed by different types of cells depending on the part of the nervous system:

• oligodendrocytes — in the central nervous system (CNS);
• Schwann cells — in the peripheral nervous system (PNS).

Each of these cells wraps around the axon multiple times, creating a multilayer lipid membrane divided by narrow sections — nodes of Ranvier. It is through these sections that the “saltatory” transmission of impulses occurs, ensuring high speed and accuracy of neural signals.

Functions of Myelin Sheaths:

• accelerate the transmission of nerve impulses through so-called saltatory (jumping) conduction;
• isolate axons, protecting them from mechanical and chemical damage;
• reduce the energy costs of neurons for maintaining action potential;
• participate in the regeneration of nerve fibers and the transmission of trophic (nutritional) signals between cells.

Composition of Myelin and Nutritional Factors

Myelin is rich in fats, especially phospholipids, cholesterol, and sphingomyelin. Important for its synthesis and restoration are:

• omega-3 fatty acids (DHA and EPA) — structural components of membranes;
• B vitamins, especially B1, B6, B9, and B12 — involved in the metabolism of neurons and the synthesis of myelin;
• vitamin D — regulates the growth and repair of myelin fibers;
• phosphatidylserine, choline, and lecithin — building blocks of the phospholipid layer;
• magnesium, zinc, and copper — necessary for enzymatic reactions and antioxidant protection of nerve cells.

Diseases Associated with Myelination Disorders

Damage or degradation of myelin sheaths leads to slowed or complete blockage of nerve conduction. This manifests as motor disorders, decreased sensitivity, and impaired memory and coordination.

Main diseases:

• multiple sclerosis — autoimmune damage to myelin in the CNS;
• leukodystrophies — hereditary defects in the enzymes responsible for myelin synthesis;
• diabetic neuropathy — chronic damage to myelin due to hyperglycemia;
• vitamin B12 deficiency — causes demyelination of the spinal cord and peripheral nerves;
• toxic damage — due to alcohol, heavy metals, medications, or viral infections.

Maintaining Myelin Health:

• ensure adequate intake of healthy fats (omega-3, choline, lecithin);
• maintain normal levels of vitamin D and B vitamins;
• avoid chronic inflammation, protein deficiency, and lack of antioxidants;
• engage in regular physical activity — it improves neuroplasticity and myelin regeneration;
• monitor blood sugar and thyroid hormone levels, as their imbalance affects nerve conduction.

Conclusion

Myelin sheaths — are a key element of a healthy nervous system. They ensure rapid and accurate signal transmission, protect axons, and support the energy balance of neurons.

To maintain their integrity, a balanced diet rich in fats and B vitamins, sufficient sunlight exposure for vitamin D synthesis, and control of factors that damage nerve tissue are necessary.

Maintaining myelin — is the foundation of cognitive longevity and normal brain function.