Vitamin D: its importance for the immune system in winter 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 deficit in dietary balance have worried 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 in the kidneys, contributing to brain development, participating in bone formation or 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 by itself,” says Eliana Reyes, nutritionist at the Universidad de los Andes clinic.

“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 a fat-soluble vitamin (which dissolves in fat), and 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. Ultimately, 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 activate in our body, it needs the sun, more than its ultraviolet B rays. Spanish Association Against Cancer They 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 small amount of sun, obviously not during the strongest hours – where it can end up damaging the skin – for this conversion of vitamin D to be correct”, adds Bastías.

Before the pandemic, Arturo Borzutzky, of the Faculty of Medicine of the Pontifical Catholic University, according to Quotation at the Institute of Public Health (ISP), pointed out that the annual average 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 at 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 complexion) would optimize vitamin D production more than a person with phototype 6 (darker complexion).

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 emphasizes the importance of fruits and vegetables, due to their content of vitamins, minerals and antioxidants.

“Since the intake of vitamin D in the diet does not normally cover the needs, it is advisable to consume supplemented foods such as dairy products, which also provide calcium and protein”, he specifies. Other sources of vitamin D are proteins with high biological value, 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 earlier, in very southern regions, where there is less sun during the year, there may be more problems obtaining this vitamin. “In the pole area there is a greater deficit, so we must generate more active research and look for alternatives to supply it,” shares Bastías, who is also part of the repertoire of the Chilean Society of Allergy and of immunology. .

A disturbing investigation carried out before the pandemic, and carried out by INTA, the U. Catolica and the 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 are already talking about an insufficient level, and below 20 ng/mL it is a deficit.

However, having this data does not mean arriving and completing on your own. The immunology specialist warns that it is very important to do an analysis that reveals the status of these organic molecules. This is a test that can be requested 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 at the forefront for obvious reasons: being at home, exposing yourself to little sunlight, aroused concern both in the medical profession and in individuals.

“Its deficit can promote bone fractures,” says Reyes, a nutritionist at the Universidad de los Andes clinic. “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 depression, reached its peak in the 1930s. At that time, according to an article published by the Chilean Journal of Pediatrics , an in-depth 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.

“Currently, patients with low vitamin D levels have been shown to have a higher risk of presenting with a severe picture of covid-19,” adds Reyes. In these times when the pandemic still does not give much respite, it is important to monitor its levels.

One of the lines of action after the worrying study that detected this deficit in different regions of the country is through milk. The objective is to fortify it, regardless of its fat or protein content. “Dairy are an easy way to reach the general population, and since it has a little fat, the ideal is that it be at least semi-skimmed, so that its absorption is easier and more efficient”, Rodrigo Valenzuela, co-author of the study and doctor of nutrition and diet, mentioned in March. 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, the various vitamins B, C or D — can be deficient in our organism and thus generate problems.

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

Unfortunately, simply taking vitamin D in supplements will not, on its own, provide us with armor against winter and respiratory infections. For this, it is important to take precautions at home, especially at this time when many children are already on winter vacation.

One of the repercussions of confinement is respiratory viruses, which cause great suffering for both parents and doctors. “Partly, outbreaks happen because children have been locked up for a long time. It’s been two years since there was almost no virus circulation and now that it’s back to normal, with schools, going out and social gatherings, these viruses are circulating again and that’s why we see more children and adults infected,” says Bastías.

Air quality – which has deteriorated – and visiting crowded and closed places also have a place in the usual exodus of virus circulation. All of this exponentially increases the risk of contagion. Here are the immunologist’s final recommendations regarding children and winter vacations.

• 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 has an influence. The cold can generate paralysis of the respiratory cilia of the respiratory tract, the small villi that help us clean viruses.
• Prefer a rather clean heating, if possible electric, in order to avoid indoor pollution. Prefer electric stoves or heaters to gas or oil, because they emit less pollution. If possible, do not use firewood.
• Air the houses well, at least twice a day.
• Maintain a healthy and balanced diet, give preference to fish, eggs, fruits and vegetables.