How To Eat To Have A Good Immune System?

The immune system is a set of biological processes and elements that allow homeostasis to be maintained against external agents. To do this, it has two levels of immune response. The first is non-specific or innate, which is made up of physical barriers, antimicrobial peptides, and the complement, among others.

The second is the specific or adaptive one, where T and B lymphocytes, as well as antibodies, intervene.

For a person’s immune function to be adequate, it is necessary to meet their energy needs, especially when the immune system is activated (when infections occur, for example).

However, this system not only requires energy to function but also specific nutrients. Therefore, it is important to know what these nutrients are, as well as the foods that provide them, when planning an adequate diet.

Foods that are friendly to the immune system

As indicated, the first step is to cover the person’s energy needs. This is essential since situations of energy deficit (malnutrition) have been linked to immunodeficiency.

However, excessive energy intake should also be avoided, which can lead to obesity. This is characterized by a state of chronic inflammation, as well as excessive adiposity. Both situations negatively affect a person’s immune function, making them more susceptible to infections.

As for macronutrients, both simple carbohydrates (sugars) and saturated fatty acids are considered to have a pro-inflammatory effect. It will therefore be necessary to limit the consumption of sweets and sugary drinks, as well as red meat, fatty dairy products, and industrial baked goods (rich in saturated fats).

On the other hand, docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), both from the omega-3 series, have been shown to have anti-inflammatory effects, as well as protection against infections. Therefore, including foods such as oily fish and nuts in the diet will help ensure the intake of these nutrients.

Proper immune function requires meeting a person’s energy needs, especially when the immune system is activated during infections. (Photo Prensa Libre: Pexels / Stanislav Kondratiev

Proteins and fiber

In the case of proteins, it has been observed that meeting a person’s intake needs favors immune function. The consumption of high-biological value proteins (from foods of animal origin and soy) is recommended. These play a fundamental role in the production of antibodies. In addition, they provide amino acids with immunomodulatory functions such as arginine and glutamine.

On the other hand, ensuring an adequate fiber intake (between 25 and 30 g/day) will also be essential for the immunocompetence of the immune system due to its prebiotic effect. This will allow for maintaining an adequate microbiota, which will favor a correct intestinal barrier function. It will also provide a direct anti-inflammatory effect (less production of pro-inflammatory cytokines) and an indirect one (through the production of short-chain fatty acids, which in turn have an anti-inflammatory effect).

On the other hand, the therapeutic use of probiotics has been proposed. These have demonstrated their anti-inflammatory effect (such as Lactobacillus rhamnosus and Bifidobacterium lactis) for the restoration of the immune system response.

The role of vitamins

As with macronutrients, minerals and vitamins also play a role in the functioning of the immune system. For example, the importance of vitamins A and D in protecting us from infections, especially respiratory infections, is well known.

To ensure an adequate intake of these vitamins, we must include in our diet meat, fish, and eggs (sources of vitamins A and D), brightly colored vegetables and fruits (sources of β-carotenes, precursors of vitamin A), and milk and fatty dairy products (vitamin D).

Vitamins E and C also play a role in immune function. They reduce oxidative stress and prevent the oxidation of both polyunsaturated fatty acids (such as EPA and DHA) and immune system cells.

In this case, vegetable oils (especially sunflower oil) and nuts provide vitamin E. Fruits (especially citrus fruits) and vegetables are the main sources of vitamin C.

It is also worth noting that fruits and vegetables provide polyphenols. These are compounds that help the immune system due to their antioxidant and anti-inflammatory effects.

Finally, deficiencies in vitamins B6 (present in protein-rich foods), B9 (green leafy vegetables, legumes, and cereals), and B12 (foods of animal origin) have been linked to alterations in the humoral and cellular immune response, inflammation, and less protection against infections.

The role of specific vitamins such as A, D, E, and C are important for strengthening the immune system. (Photo Prensa Libre: Vanessa Loring)

And the minerals?

As for minerals, it is worth highlighting the importance of all of them, but especially zinc (red meat, legumes, crustaceans, and mollusks) in the immune system. The latter participates in the maintenance of membranes, as well as in the growth and differentiation of immune system cells.

Iron (meat, fish, legumes, and green leafy vegetables) is another mineral to consider due to its importance in the growth and differentiation of T lymphocytes, just as copper (whole grains, nuts, legumes, crustaceans, and mollusks) and selenium (red meat, fish, eggs, seafood, and whole grains) are necessary for the proliferation of T cells, antibody production, and cellular immunity.

Finally, it should be noted that maintaining an active lifestyle can be beneficial for the immune system. Numerous studies have shown that physical activity not only has an anti-inflammatory effect but also helps regulate the immune system and delays age-related loss of functionality.