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Vitamin D – sunshine vitamin: definition, importance and synthesis

Have you ever heard of the sun’s vitamin?

Vitamin D, or sun vitamin, as it is commonly called, is one of the most important vitamins for our body because it is also more common to have deficiency of this vitamin.

As such, it is essential to ensure that our body has good levels of vitamin D.

Do you know what the recommended doses are, how important it is and how you can keep good levels of this vitamin on your body?

See everything in this article!

Vitamin D: What is and what are its main functions?

vitamin D

Vitamins, together with minerals, are part of the micronutrient group. They are essential to maintain a good overall functioning of our body.

All vitamins are important and have their own characteristics, but vitamin D is special because it works like a hormone.

Vitamin D can be found in two main forms:

  1. Vitamin D2 (or Ergocalciferol)
  2. Vitamin D3 (or Cholecalciferol) (can be formed by solar irradiation)

To be transformed into active compounds–in vitamin D–they undergo chemical processes in our body.

Vitamin D performs several functions in our body at various levels: cellular, muscular, bony, among others.

Vitamin D functions

  • Contribute to the normal absorption/use of minerals calcium and phosphorus, something that plays an important role in the promotion of bone health
  • Contribute to normal muscular function
  • Contribute to the normal function of the immune system
  • Can contribute to the reduction of inflammation

The recommended daily values of vitamin D for adults between 19-50 years is at 600 IU/day.

The overdose (which can cause intoxication) is not common, but this can be translated into excess calcium in our body, which can cause nausea, vomiting, lack of appetite, fatigue and an abnormal heart rhythm. For example, values between 200-250 ng (ML (500-750 nmol/L) may reveal an excess vitamin D.)

Values below 30 NMO/L (12 ng/ml) are too low and indicate vitamin D deficiency. Values between 20-50 ng/ml are considered suitable for healthy people.

The lack of vitamin D can bring several problems.

See some of the main examples!

Major problems that may arise from the lack of vitamin D

Studies show that low levels of vitamin D are correlated with a higher risk of developing other pathologies other than vitamin D deficiency, such as:

  • Loss of bone mass
  • Osteoporosis
  • Loss of cognitive abilities

Therefore, to stay healthy and to avoid some of these pathologies, it is necessary to maintain good levels of this vitamin.

How can you get vitamin D?

You can get vitamin D in three different ways:

  • Through solar exposure
  • Through feeding
  • Through supplementation

Solar Exposure

solar exposure

According to the article “Vitamina D-importância da avaliação laboratorial

“Can be synthesized on the skin from exposure to sunlight (ultraviolet radiation in the range of 290-315 nanometers)”.

Therefore, knowing that vitamin D can be synthesized/produced through the contact of our skin with sunlight, it is easy to see why this vitamin is also called the Sun’s vitamin.

However, the synthesis of vitamin through solar exposure is not a constant. There are several factors that can influence that.

For example:

  • In the northern countries it is more common to lack vitamin D.

According to the study “vitamin D: An Overview of vitamin D status and intake in Europe”:

“In the northern hemisphere at latitudes greater than around 40°N sunlight is not strong enough to trigger synthesis of vitamin D in the skin from October to March.”

  • People with dark skin – with greater pigmentation – have more difficult to synthesize this vitamin.
  • Season of the year. In the summer month, as a norm, there is a greater solar exposure, the opposite happens in the winter months.
  • Weather conditions.
  • Use of sunscreen. Although its use is very important, to ensure the protection of the skin against ultraviolet (UV), it also limits the synthesis of vitamin D. Opting for the hours when the UV have a lower intensity can help to avoid the harms of the sun.

15/30 minutes of solar exposure may, according to some specialists, result in sufficient vitamin D values.  Do not forget to apply sunscreen at the end of this time and, in the most sensitive and exposed parts, put as soon as you are in contact with the sun!

To avoid being exposed to the sun without sunscreen, there are other things that can help you keep good levels of vitamin D in your body, as you can see further ahead.

  • Skin covered by clothing.
  • Less outdoor activities.

Other factors that vary the levels of vitamin D in the body are hormonal, genetic and nutritional factors.

Even if the sun exposure is long lasting, this will not cause excess vitamin D in the body, because our body stores it so that it is used when there is need.


Vitamin D can be obtained by food.

Vitamin D can be found in some foods, (of which stand out, mainly, food of animal origin), especially in fish: tuna, salmon, mackerel, herring. But it can also be found in eggs, in milk (in the case of vitamin D3) and in mushrooms (in the case of vitamin D2), for example.

For people who follow a vegan diet, it can be more difficult to get vitamin D through food, which is why supplementation can be a good alternative.


vitamin D supplements

In Portugal, and a little everywhere, vitamin D supplements are available to help supply the deficiencies in this micronutrient.

In these supplements, vitamin D is made available in the form of vitamin D2 or vitamin D3.

However, studies show that:

“Supplementation with vitamin D(3) may be preferable to vitamin D(2).”

Other studies have demonstrated that vitamin D3 was three times more potent to improve or maintain vitamin D levels in the body than vitamin D2.

In Zumub you can find several supplements of this vitamin. Check the availability.

The use of vitamin D supplements is so common that vitamin D supplementation is already included in some countries ‘ health policies.

Attention! Supplementation should not be used as a prevention of any disease or improvement in the quality of life without any type of recommendation or advice. The need to be identified and their consumption must be duly monitored by health professionals.

Vitamin D: in conclusion

As you can see, vitamin D is essential for everyone, because it is responsible for various functions of our body.

Our current lifestyle that can prevent us from being exposed to the sun long enough to enhance the synthesis of this vitamin, the lack of care with food or the difficulty in consuming foods rich in this vitamin, can be an obstacle to obtaining good levels of vitamin D.

Therefore, supplementation may be the easiest and purest way to obtain this vitamin and to avoid vitamin D deficiencies.

Try it now!

zumub vitamin D suplements


The information included in this article concerns the authors opinion only.

About Ângela Ferreira

Ângela Ferreira
Ângela Ferreira is a nutritionist. She has a degree in Nutrition Sciences and she is doing a Master's degree in Consumer Sciences and Nutrition. She currently works in Sports Nutrition and Clinic Nutrition. Her goal is to actively participate in changing the population's eating habits and to demonstrate that healthy eating can be simple and practical.

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