We can’t lock ourselves in a glass bubble to avoid getting sick — we absolutely can’t avoid all dangers, what kind of life would that be. What we can do is strengthen our immune system.

The immune system is a complex network of cells, tissues, organs, and the substances they produce. Its main role is to protect the body. So, the immune system has to deal with pathogens like bacteria, viruses, parasites or fungi, harmful substances from the environment, and disease-causing changes within the body, such as cancerous cells.

Close your eyes and imagine your immune system as a super-machine with millions of levers, switches, wires, lights, and all of them interacting. So, you can understand how difficult it is to refer precisely and in detail to all that can interact and strengthen or weaken its function.

What strengthens the immune system:

• Good, balanced diet

• Sufficient, quality sleep

• Exercise

• Good hydration

What weakens the function of the immune system:

• Stress

• Alcohol

• Smoking

• Poor diet and inadequate sleep

We’ll focus on nutrition. Some nutrients affect the creation of immune cells, some help with inflammation, some strengthen the gut microbiota and thus relate to immunity, and others act as anti-cancer agents. So it’s impossible to mention all the beneficial foods and nutrients in detail, but we will cover quite a few.

Omega-3
Long-chain polyunsaturated fatty acids, especially omega-3 fatty acids, have strong anti-inflammatory ability, while trans fats—especially from processed foods like fried foods, chips, etc.—have pro-inflammatory properties.

Where to find omega-3 (mainly in fatty fish):

• Herring

• Salmon

• Sardines

• Trout

• Mackerel

We try to consume fatty fish at least once a week.

Carbohydrates and Fiber
A meal with a high glycemic index has been associated with an immediate increase in inflammation.

Examples of high-GI foods: sweets, cakes, cookies.

Less processed foods with low GI, such as vegetables, fruits, nuts, seeds, and whole grains, do not cause such adverse inflammatory effects after a meal.

Significant reduction in inflammation has been observed with increased fiber consumption (about 30 g/day).
It is recommended to intake 25 g – 38 g of fiber for women and men, respectively.
Another benefit of consuming whole grains is also a more favorable composition of gut microbiota, which reduces both gut and systemic inflammation. Even small increases—only 5 g more fiber per day—can be beneficial.

Protein
Low protein status due to insufficient protein intake—below the recommended 0.8 g/kg of body weight, as suggested by the RDA—is well known to increase the risk of infection.
Usually, this phenomenon appears in developing countries or in people who, for any reason, are not eating adequately.

Of course, protein is a sensitive matter since it usually comes from animal products with high levels of saturated fat and the result may be pro-inflammatory.
So, intake of high biological value protein from healthy dietary choices—like eggs, fish, lean meat (e.g., poultry), and low-fat dairy protein—when consumed with meals, can reduce postprandial lipogenesis and inflammation.

In addition, consumption of a certain amount of high biological value proteins is known to be necessary for antibody production.

Glutamine
Glutamine plays a key role in the immune system (it is the most abundant amino acid in the body).

Important sources of glutamine: beef, egg, and tofu.

Micronutrients

• Vitamin A deficiency has been linked to increased risk of infection.
  Sources: liver, salmon, eggs, milk, sweet potato, carrots.
• Vitamin D can be obtained from the diet through fish, eggs, fortified milk, and mushrooms, but can also be synthesized under the skin in the presence of UV radiation from cholesterol.
• It has been shown to regulate the immune system.
• Vitamin E is found in nuts and vegetable oils, in some seeds and cereals.
• Vitamin C: citrus fruits, peppers, broccoli, and several others.
• Low zinc status has been associated with increased risk of viral infections. Sources: meat, poultry, fish, and more.
• Iron deficiency is linked to infectious diseases.
• Copper has been shown to play a role in innate immune response to bacterial infections.
• Selenium also plays an important role in the immune system. Some sources: poultry, eggs, seafood, beans, shellfish, Brazil nuts, etc.

Probiotics
Probiotics are defined as “live microorganisms which, when administered in adequate amounts, confer a health benefit on the host.”

Probiotics can regulate immune system responses, while dysbiosis—that is, the replacement of normal gut flora with a dysfunctional lineup of organisms—can promote disease states.

Foods that contain probiotics: kefir, certain yogurts, pickled cucumbers, some cheeses, kombucha, and others.

Conclusion: a balanced diet to support your immune system. Omega-3 fats, complex carbohydrates and fiber, good low-fat protein sources, micronutrients through a variety of foods, probiotics if possible, and limiting alcohol, saturated fats, and especially trans fats which are mainly found in ultra-processed foods.
Adequate quality sleep, exercise, and as much stress reduction as possible.