Fat-soluble vitamin D, in addition to being ingested with some types of foods, is synthesized by the human body from exposure of the skin to sunlight. Something that we can take advantage of during day walks.
Its fundamental physiological role is to ensure the plasma levels of calcium and phosphate necessary to achieve favorable conditions for bone mineralization.
Types of vitamin D
Probably, many of you have heard that it can exist in various forms and you are indeed correct:
- Ergocalciferol or D2
Obtained through diet and absorbed, thanks to the presence of fats in the duodenum and jejunum.
- Colecalciferol or D3
Synthesized in the skin of mammals by the action of ultraviolet B radiation, although there may also be an external contribution through some foods and supplements.
- Calcidiol or 250HD
The mode in which vitamin D is stored originates in the liver after D3 binds to its binding protein.
- Calcitriol or 1,250HD
The active version, arises as a result of the hydroxylation of Calcidiol, a chemical reaction that occurs mainly in the kidneys.
What kind of foods is vitamin D?
In reality, there are not many edible products that in their natural state contain this beneficial substance. Some fish such as salmon, tuna, herring, conger eel or prawns are the best supplies of vitamin D, present to a lesser extent in beef, liver, cheese and egg yolk.
We can also find foods that after a manufacturing process, acquire it or increase its concentration. Sun drying fish liver oils, the best known natural source, is a good example of this.
How much vitamin D do you need at each age?
Depending on the stage of life we are in, the recommended daily doses vary. International medical authorities agree on the following relationship, expressed in micrograms (mcg) and in international units (IU), which in the case of vitamin D are equivalent to 40 mcg.
- Babies up to 12 months 10 mcg (400UI)
- Children 1-13 years 15 mcg (600UI)
- Teenagers from 14 to 18 years old 15mcg (600UI)
- Between 19 and 70 years old 15mcg (600UI)
- Over 71 years of age 20mcg (800 IU)
Recommendations to avoid vitamin D deficiency
Specialists advise that children and adolescents follow a diet rich in vitamin D. In addition, they consider it necessary to carry out physical activity and a sensible sun exposure for at least 15 minutes during the day, that allows them to adequately expose face, arms and hands.
Regarding its intake from artificially synthetized sources, we must be very clear avoiding an overdose, which can forces us to have to seek medical attention. In fact, unless a person is among the population at risk of suffering from this substance`s deficiency, its intake in its synthetized form (pills) is usually not essential.
The amount of vitamin D the body produces depends on many factors including the time of day, season, latitude and pigmentation of the skin. Depending on where you live and your lifestyle. That is why it is important to know the recommended amounts that we should consume.