Vitamin D: why it is so important for the immune system and how to ingest it

Much has been said during the pandemic and the periods of confinement of vitamin D. The lack of exposure to the sun and the concern of a lack of balanced diet worry the medical profession. In parallel, patients hospitalized due to covid were supplemented with this vitamin as part of their treatment. This is how to this day we continue to talk about this important micronutrient.

Among its main functions is the strengthening of the immune system, in addition to regulating the excretion of calcium and phosphorus at the renal level, contributing to brain development, participating in bone formation and its important anti-inflammatory role. However, it is not a question of arriving and ingesting it in the form of pills or supplements: this requires a medical follow-up beforehand.

“It is an essential vitamin that participates in the functions of the whole organism, and if it is not provided by conversion in the skin —by the sun— or in the diet —by certain foods—, the organism does not cannot replace it with another vitamin or synthesize on its own,” says Eliana Reyes, nutritionist at Clínica Universidad de los Andes.

“Vitamin D mainly helps macrophages, those cells of the immune system that help eliminate infections, to do their job well,” explains Carla Bastías, immunologist at Clínica Dávila. It is precisely for this reason that the levels of this vitamin must be adequate for its proper functioning.

“Vitamin D is fat-soluble (it dissolves in fat), and it has an important action on muscle contraction and nerve impulses,” Daniela Marabolí, nutritionist and brand advisor, explained to us in another article. Biological flow . It also contributes to immunity because it induces the formation of proteins and, on the other hand, its adequate intake is associated with a preventive role in certain types of cancer. Lately, its presence is associated with the prevention of various chronic diseases, such as high blood pressure, cardiovascular disease, diabetes, osteoporosis and even obesity.

For vitamin D to be activated in our body, it needs the sun, more than anything else, its ultraviolet B rays. Spanish Association Against Cancer suggest that daily exposure to the sun for 8-15 minutes, always with a sun protection factor, is enough to generate the vitamin D your body needs.

“It is recommended to take a little sun, obviously not at the strongest hours – when it can end up damaging the skin -, so that this conversion of vitamin D is correct”, adds Bastías.

Before the pandemic, Arturo Borzutzky, of the Faculty of Medicine of the Pontifical Catholic University, according to cited at the Institute of Public Health (ISP), pointed out that the annual average of UVB solar radiation in Chile varies considerably depending on the area: while in Parinacota it is high (5.03), in the metropolitan area it is intermediate (3.15) and in Magallanes very low 1.11. This means that people in very southern latitudes are at high risk of having a severe deficiency.

All this, in turn, is related to each person’s skin phototype. In other words, a person with phototype 1 (very white skin) would optimize the production of vitamin D more than a person with phototype 6 (darker skin).

But in addition to sunlight, vitamin D can also be found in various food sources. “To have a healthy immune system, it is necessary to have a balanced diet, which includes all food groups, we hope every day”, explains the nutritionist. This is why he insists on the importance of fruits and vegetables, because of their content of vitamins, minerals and antioxidants.

“Vitamin D intake in the diet is not normally sufficient to cover needs, it is advisable to consume supplemented foods such as dairy products, which also provide calcium and protein,” he says. . Other sources of vitamin D are high biological value proteins such as eggs, other dairy products such as cheese and butter, white meats such as fish and shellfish, and legumes, which provide proteins and minerals.

As we mentioned before, in very southern regions, where the sun is less permanent during the year, there may be more problems obtaining this vitamin. “In the field of the poles there is a greater deficit, so it is necessary to generate more active research and to look for alternatives to supply it”, shares Bastías, who is also part of the board of directors of the Chilean society. of Allergies and Immunology.

A disturbing survey conducted before the pandemic and carried out by INTA, U. Católica and U. Finis Terrae, revealed that vitamin D levels were deficient in the population of different cities, such as Antofagasta, Santiago and Concepción, where 70% of the population showed low amounts. How normal is it? According to the study, a person with a sufficient level of vitamin D has 30 nanograms per milliliter (ng/mL) in the blood. Between 30 and 20 ng/mL we already speak of an insufficient level, and below 20 ng/mL it is a deficit.

This is why since July 2024, according to an official decree published last year, all milk sold in Chile – liquid or powder -, as well as flour, must be enriched with vitamin D3. Because these are products that are widely consumed in the country —especially the second, through bread—, the serious vitamin D deficiency could begin to reverse.

But that’s still a year away. How to reinforce, in the meantime, this lack of vitamin D? The immunology specialist warns that it is not a question of arriving and completing oneself. It is very important to carry out an analysis that reveals the state of these organic molecules in our organism. This is a test that can be ordered and monitored by most doctors, so it can be done by a pediatrician, in case you want to see your children’s levels.

During the longest periods of confinement, vitamin D was in the spotlight for obvious reasons: being at home, exposing yourself to little sunlight, aroused concern both in the medical community and among individuals.

“Its deficit can promote bone fractures,” says Reyes, a nutritionist at the Clínica Universidad de los Andes. “It also controls many additional biological activities related to the immune and cardiovascular systems, skin and muscle function, cell growth control, and many other biological processes.”

Serious cases of deficiency, according to Bastías, are few in our country, since rickets, a disease associated with this deficiency, reached its peak in the 1930s. At that time, according to an article published by the Chilean Journal of Pediatrics , an exhaustive investigation has been launched to treat and prevent it. On the other hand, the immunologist describes that what a person with severe vitamin D deficiency might experience is muscle weakness, joint pain or cramps in general.

One of the lines of action after the worrying study that detected this deficit in different regions of the country is through milk. The goal is to fortify it, regardless of its fat or protein content. “Dairy products are an easy way to reach the general population, and since they contain some fat, they should ideally be at least semi-skimmed, so that their absorption is easier and more efficient,” says Rodrigo Valenzuela. , co-author. in March of the study and the doctorate in nutrition and food and director of the dairy scientific committee.

Bastías deepens that, more than vitamin D, we must be aware that all vitamins are necessary for the immune system to work in the best possible way. This is the importance of a balanced diet: without this variety, trace elements — such as vitamins A, different B, C or D — can be deficient in our organism and thus generate problems.

In addition to a balanced diet and moderate sun exposure, sport or physical exercise also plays an important role in this engine, since “it allows certain protective substances to be broken down”, specifies the immunologist. “A healthy diet and a healthy life” is a true expression, since “it is what most helps a person without underlying pathologies to have a healthy immune system”.

Unfortunately, ingesting vitamin D in supplements for fun will not by itself build armor against winter and respiratory infections. For this, it is important to take refuge at home, especially in this period when various viruses – syncytial, flu, rotavirus and still covid-19 – are on the prowl.

In the usual exodus of circulation of viruses, there is also room for air quality -which has deteriorated- and that on cold days we stay in more closed spaces, less ventilated and with a density of higher people. All this cocktail exponentially increases the risk of contagion. Here are the immunologist’s final recommendations, primarily for boys and girls.

• Avoid closed or crowded places, where there is little ventilation or where there are many people, as this promotes respiratory infections.
• Avoid sudden temperature changes, as this also influences. The cold can cause paralysis of the respiratory cilia of the airways, the small villi that help us clean out viruses.
• Prefer a rather clean heating – electric, if possible – in order to avoid any intra-domiciliary contamination. Prefer electric stoves or heaters over gas or oil, as they emit less pollution. If you can, don’t use firewood.
• Ventilate houses well, at least twice a day.
• Maintain a healthy and balanced diet, favoring fish, eggs, fruits and vegetables.