What is the immune system, where is it located, and how does it work?
The immune system is a complex network of cells, organs, and biological mechanisms that works every day—often without us realizing it—to protect us from viruses, bacteria, and other external threats. Each of these parameters has the task of protecting the body from external pathogens (viruses, bacteria, fungi, parasites) and internal alterations (such as tumor or damaged cells). It is our "biological shield," active 24 hours a day to keep us healthy.
Our immune system is divided into two main lines of defense: innate immunity, which comes into action quickly and widely, and acquired immunity, slower but highly specific and able to “remember” pathogens already encountered.
Key cells include:
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- T and B lymphocytes (adaptive immunity)
- Macrophages, neutrophils and NK cells (innate immunity)
- Dendritic cells, which act as a bridge between the two systems
In addition to immune cells and antibodies, other main components are:
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- Primary lymphoid organs: bone marrow and thymus, where immune cells originate and mature
- Secondary lymphoid organs: lymph nodes, spleen, tonsils and Peyer's patches, which house immune cells and coordinate the response
- Mucosal-associated immune system (MALT): located in the intestine, lungs and urogenital tract, it is one of the first lines of defense
The immune system is flexible and dynamic, but also vulnerable: external factors such as stress, an unbalanced diet, pollution, and a sedentary lifestyle can compromise its effectiveness.
Lifestyle: the first real daily immunotherapy
Sleeping well isn't just a pleasure: it's a valuable ally for a healthy immune system. During the night, the body produces cytokines, key proteins that coordinate immune and inflammatory responses. When sleep is poor or irregular, antibody production is reduced and the activity of T lymphocytes, the cells that defend us from viruses and bacteria, is weakened. This is why it's essential to sleep at least 7–8 hours a night, adapting your sleep to your age and trying to respect your natural circadian rhythm as much as possible.
Even good hygiene habits, often underestimated, play a decisive role in prevention: washing your hands regularly, airing the rooms, storing food correctly are simple but extremely effective actions in limiting contact with pathogens.
However, be careful not to indulge in these habits too much: an overly sterile environment can reduce the immune system's ability to function, especially in younger children. Controlled exposure to environmental microbes can contribute to better immune regulation and a lower incidence of allergies.
Finally, one of the most insidious enemies of our immunity: the chronic stress.
Cortisol, the stress hormone, when persistently present, suppresses the immune response, inhibiting the production of lymphocytes and the physiological inflammatory response. Breathing techniques, meditation, yoga, nature walks, or creative activities help restore inner balance and strengthen the mind-body connection, promoting a healthy psycho-neuro-immunological balance.
Physical activity and the immune system: they're allies, but be careful not to overdo it!
Regular, moderate physical activity is one of the most effective ways to strengthen your immune system. Exercise stimulates circulation, promotes cell turnover, and improves your immune system's response to pathogens.
However, be careful with excessive or unrecoverable exercise (overtraining): it can have the opposite effect, inducing a state of temporary weakness (a phenomenon known as the "open window"), with a reduction in salivary IgA (immunoglobulins essential for the immune response) and greater susceptibility to upper respiratory tract infections.
The key? Listen to your body.
Your needs change with age, but in general, it's recommended to alternate light, sustained aerobic activity (such as walking, moderate running, or cycling) with shorter, more intense sessions. Do this three or four times a week, and plan to have some unwinding weeks to allow all your systems to recover optimally.
Diet: the first medicine of the immune system
A balanced and varied diet is the biological basis for maintaining a strong and efficient immune system. Nutritional deficiencies (macro and micronutrients) can compromise the production of immune cells and antibodies. To truly support our defenses, It is essential to choose foods that are as little manipulated as possible.Rich in vital nutrients and free from excessive additives and preservatives, simplicity in cooking is often synonymous with health.
Here's what should never be missing from the table:
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- Proteins: essential for the synthesis of antibodies and cytokines. A low-protein diet weakens the immune system.
- Omega-3 fatty acids (DHA, EPA): with powerful anti-inflammatory and immunomodulatory effects
- Vitamins (A, C, D, E, B6, B12, folates): essential for the maturation and activation of immune cells
- Minerals (zinc, iron, selenium, copper): enzyme cofactors in the immune response.
- Prebiotic fibers: they promote a healthy microbiota, which is essential for 70–80% of intestinal immunity. A balanced microbiota (“eubiotic”) promotes the production of short-chain fatty acids, (SCFA) such as butyrate, which positively modulate inflammation and immune tolerance.
Therefore, the green light is given to meat and fish from organic farms, unrefined cereals from multiple sources, seasonal fruit and vegetables, and eggs (always from free-range farms).
Taking care of your immune system is a long-term wellness choice
The immune system is not an isolated entity, but a sophisticated ecosystem that responds dynamically to external and internal stimuli. correct lifestyle, one constant physical activity, one varied and nutrient-rich diet and a targeted integration can make the difference between an efficient response and prolonged vulnerability.
Taking care of your immune system means investing in your long-term well-being: not only avoiding seasonal flu, but also improving your body's overall balance, recovery ability, and quality of life.
