Vitamin D or vitamin from the sun requires sunlight and a good diet to be produced, but there are other factors to take into account to improve its production.

A woman sunbathes with a mask.

Vitamin D or “vitamin from the Sun” has become very popular in recent years in Spain, especially as a result of the Covid-19 pandemic: confinement prevented the necessary sun exposure, origin of between 80-90% of the vitamin D that the human organism generates, being the other 10% through the diet.

Likewise, some studies have linked the Vitamin D deficiency with a poor prognosis after contracting Covid-19, and including a increased risk of infection of the coronavirus that causes it, although it is something that continues to be investigated even today.

The process to obtain vitamin D is complex and requires a multitude of factors, being the sun exposure and diet the most important and well-known, in addition to dietary supplements. But today, thanks to Harvard University, we will review other six things to keep in mind regarding vitamin D.

The place where we live

The country where you live is an important piece of information when looking to obtain vitamin D: the farther a country is from the terrestrial Ecuador, the less UVB light, which produces vitamin D, reaches the surface of the Earth, and therefore less sun exposure will have the inhabitants of these countries.

Thus, the Nordic countries have zero sun exposure for much of the year, which is why they suffer from a certain tendency towards vitamin D deficiency. Even in Spain, during the winter months, where the day is shorter and more clothes are worn, the vitamin D deficiency tends to increase in the population.

But to all this we must add some more information: In Spain there is a huge deficit of vitamin D despite being a country exposed to the Sun much of the year. The lifestyle inside homes and office jobs may be the culprits, but not the only points to take into account, as we already explained in ‘EL ESPAÑOL’.

Air quality

Another point to take into account, as Harvard experts well recall, is air quality. And it is that floating carbon particles in the environment, from the burning of fossil fuels, wood and other materials, scatter and absorb UVB rays, blocking its action on human skin and therefore the production of vitamin D.

In contrast, the ozone layer absorbs UVB radiation, so the holes caused by such pollution could even improve vitamin D levels, although such holes are a clear environmental problem.

So that, the more industrialized a country and the greater the base in fossil fuels, the worse for health: Environmental pollution not only increases the risk of cardiovascular and lung disease, but also reduces sun exposure and the production of vitamin D.

Using sunscreen

While the use of sunscreen is necessary to avoid sunburn caused by the same UVB radiation, using it excessively can be a problem: in theory, the sunscreen would also prevent exposure to light, which would reduce vitamin D levels.

However, as the experts of Harvard, on the practice very few people put on enough sunscreen to block exposure to UVB light, or they use it very irregularly, so effects of sunscreen would be unimportant as far as vitamin D production is concerned.

Skin color

Melanin is the substance in the skin that causes its dark color: the more melanin, the less vitamin D productionSince this substance “competes” with the substance that causes the production of this vitamin in terms of absorption of UVB light.

So those people with darker skin tones often require more exposure to UVB rays than lighter-skinned people: better sunburn protection, yes, but lower vitamin D production as well.

Body weight

Body weight also participates in the production of vitamin D: body fat absorbs vitamin D, so it has been suggested that this fat could function as “Warehouse” for this vitamin when it is not conveniently obtained from sun exposure or diet.

However, some studies have shown that obesity is correlated with lower levels of vitamin D, and that mere overweight can affect its bioavailability, so it is not clear that having more fat is really beneficial in this regard.


Finally, age would also be a factor to take into account, since the younger people tend to have better vitamin D levels than older people.

This is due, according to studies, to the fact that older people have lower levels of the skin substance that would become a vitamin D precursor after sun exposure. Likewise, there is evidence that older people are less efficient at producing vitamin D than the youngest.

Therefore, as can be seen, not everything is sun exposure and diet. There are many other factors to consider within the general lifestyle.