It is an undeniable fact that in the times of the COVID-19 pandemic we went out much less, trying to avoid contact with other humans. Now that summer is over, we may be going out even less. However, staying at home longer than usual can contribute to the decrease in the levels of vitamin D that we have in the body.

What levels of Vitamin D in the blood are considered normal?

In Spain, the references are as follows:
Deficiency: <10.
Insufficiency: 10-30.
Sufficiency: 30.01-100.
Toxicity: >100.

Vitamin D, vitamin D2, or vitamin D3?

Vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol) are simply two different forms of vitamin D. The former is formed in the skin under the influence of ultraviolet rays in sunlight and also comes from animal sources. The latter comes from plant sources. They are measured in international units.

How is vitamin D synthesised?

Vitamin D is formed in the skin when it is exposed to sunlight, through ultraviolet B rays, which help synthesise vitamin D. These rays cannot pass through glass, clothing or sunscreen.
On the other hand, it can enter the body along with certain foods. First of all, these are fatty sea fish, fatty dairy products and egg yolks.
However, if you are deficient or insufficient in this vitamin, you cannot get enough of it from food or sunlight alone (on top of that, ultraviolet rays can also be dangerous). For example: the daily intake of vitamin D is contained in 20 egg yolks. Therefore, taking vitamin D supplements is the best option in case of deficiency or insufficiency.
Furthermore, in practice, milk and dairy products do not always contain vitamin D or contain only its insignificant traces, so their consumption, unfortunately, cannot guarantee the coverage of our needs for this vitamin.

Why is it a good idea to try and avoid vitamin D deficiency and insufficiency?


The main function of vitamin D is to regulate the metabolism of calcium and phosphorus. It helps the absorption of these elements from the intestines, thus participating in the growth and maintenance of bones and skeleton. If this vitamin is lacking in the body, a person can develop rickets and osteoporosis.
On the other hand, in almost all organs and tissues, there are receptors for vitamin D. Therefore, it has a large number of functions not only related to the development and growth of bones.
It also plays a role in the development of the nervous system. With its deficiency, sleep disturbances and cognitive disorders such as memory impairment can occur. In adults, it can contribute to the development of Alzheimer’s and Parkinson’s diseases, or senile dementia.
In many cases, people with vitamin D deficiency are at increased risk of developing cancer, cardiovascular diseases, infectious diseases, and many others.
Its deficiency is also one of the factors that increase tissue resistance to insulin, contributing to the development of diabetes. This prohormone is also a powerful agent for reducing chronic inflammation.

Some peculiarities to take into consideration.

Elevated vitamin D levels can lead to functional vitamin K2 deficiency. In this case, since vitamin K2 regulates calcium transport, calcium does not reach the bones and is deposited in the arteries and soft tissues, which can lead to hardening of the arteries.
So, if you take vitamin D, you create a higher demand for vitamin K2 in your body. Both vitamin D and K2 work together to strengthen your bones and improve the health of your heart. Therefore, if you are taking vitamin D via supplements, you also need to intake extra vitamin K2.

Who needs vitamin D the most?

An increased need for vitamin D arises from a lack of ultraviolet radiation, naturally dark skin, old age, vegetarianism and adherence to low-fat diets, indigestion, pregnancy and lactation, a period of intensive growth and development. These people need additional vitamin D. Therefore:
– Pregnant or breastfeeding women: vitamin D deficiency during pregnancy leads to inadequate formation of the fetal immune system.
– Children: in children, vitamin D deficiency leads to a sharp deterioration in anti-infective protection. Frequent illnesses can be a consequence of this vitamin’s deficiency or insufficiency.
– Older people: ageing skin loses its ability to synthesise vitamin D, and older people are most at risk of developing all kinds of previously mentioned diseases.

And so now what?

Taking a walk in the sun for just half an hour a day would be enough in our area in Spain to activate vitamin D, provided that its intake from the diet or through supplements is adequate.
At Clínica La Siesta, we carry out the 25-hydroxy vitamin D (25-OH Vitamin D) test, which is considered the most effective way to measure the amount of this vitamin in the blood. If in doubt, you can consult our GP to determine if you need to check your blood vitamin D level.
By knowing exactly what levels of vitamin D you have in your blood, you can take appropriate action. Only the doctor can assign the doses of supplements necessary for each particular case, since it will depend on the level of vitamin D already present in the blood, the person’s lifestyle, their nutrition and the climate of the country of residence. In addition, an overdose of vitamin D can also have serious adverse health consequences, so it is best to consult your doctor. To make an appointment at CLS, please contact us by email info@clinicalasiesta.com, by calling us at +34 966 784 195, or by writing us a WhatsApp to +34 692 134 136.