Vitamin D and its deficiency in the human body

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Many types of vitamins and trace elements are needed for the healthy functioning of the body. The role of vitamin D has been addressed more intensively in recent years than before. Its effects have been found to be not limited to bone metabolism. Experts are also increasingly drawing attention to the fact that vitamin D plays an important role in the body’s immune (defense) processes.

What is vitamin D?

 Vitamin  Dis a micronutrient that the human body produces itself, so it is not a vitamin. It’s more of a hormone. This is most often done by the fact that sunlight produces vitamin D in the skin, from where it enters the liver through the blood and then into the kidneys.

Most of the vitamin D that enters the body is made from provitamins found under the skin when activated by sunlight. This substance also affects the level of calcium in the blood and directly promotes the storage of calcium in the bone tissue.


Natural sources of vitamin D

A good, varied and healthy diet can also support the production of vitamin D. Its best sources are fish liver oils, liver, eggs, milk and dairy products, margarines. It is important to mention once again that it is formed mainly in the skin by sunlight. Unfortunately, polluted air also affects this process, because harmful substances in the atmosphere absorb ultraviolet rays. As a result, less vitamin D is produced in the skin.

 The function of vitamin D in the human body

The primary biological function of vitamin D is to maintain normal levels of calcium and phosphorus in the blood, but it also plays a primary role in calcium absorption and the formation and maintenance of strong bones. Recent research suggests that it protects against osteoporosis, high blood pressure, cancer and many autoimmune diseases.

It plays a central role in bone development. If young children have low levels of vitamin D, their bones cannot grow and strengthen properly. This means that the support system will not be stable even in adulthood. Dental health and a tendency to tooth decay are also linked to vitamin D intake. This substance is particularly important in people with gum atrophy.

Vitamin D treats psoriasis. People with this disease usually have low levels of vitamin D, and if they increase their daily intake of this micronutrient, they also reduce the intensity of symptoms.

 What can lead to vitamin D deficiency?

If, for some reason, the metabolism of vitamin D is impaired or does not function sufficiently, there is a strong risk of vitamin D deficiency. The level of active vitamin D is usually determined from the blood. In such examinations, attention is also paid to whether the person has elevated calcium levels.

Since the primary source of vitamin D is the sun, one of the most frequent reasons for vitamin D deficiency is, logically, insufficient contact with natural light. It occurs mainly in the elderly or when wearing clothes covering the entire surface of the body.

Other possible causes of vitamin D deficiency:

  • malnutrition,
  • reduced ability to absorb vitamin D from the gut (eg in people with celiac disease),
  • increased consumption of vitamin D (pregnancy, lactation, growth in children),
  • taking certain medicines (eg antiepileptics).
  • increased kidney function,
  • nephrosis,
  • impaired renal function,
  • parathyroid dysfunction,
  • increased activity of the thyroid gland (hyperthyroidism)
  • some types of rickets,
  • cadmium poisoning.

Vitamin D deficiency in adults can cause health problems such as osteoporosis, muscle cramps and rapid tooth damage.


Types of vitamin D

Vitamin D is the collective name for two types of vitamins: vitamin D2 and  vitaminD3 . Their biological value is the same for the human body, but in terms of biological effect, vitamin D3 is more active than vitamin D2. This means that vitamin D3 can be processed more easily by the body.

Vitamin D2 is found in large amounts in, for example, yeast, some types of fungi and rye sponges. Vitamin D2 of animal origin is found in some types of fish oil.


In nature, D3 is more common, and is formed mainly in contact with sunlight. If you want to learn more about this vitamin directly from experts, be sure to visit In addition to useful information, you will also find quality food supplements and vitamins.


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