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Vitamin D | Feature | Sources in food | deficiency

Basic characteristics of vitamin D

Vitamin D is one of a group of fat-soluble vitamins, along with vitamin A ,E & K. 

It was discovered in the twenties of the last century, when the investigation shows that ultraviolet rays from sunlight affect the production of vitamin D in the skin of humans.

It is known more precursors of vitamin D, but two are most important:

- Ergocalciferol or Vitamin D2
- Vitamin D3 or holecalciferol

Ergocalciferol is produced from provitamin ergosterol, while cholecalciferol is created under the influence of solar radiation in the skin.

Further metabolism going in the direction of converting provitamin to vitamin D, which takes place in the kidneys, where it produces the active form - calcitriol, which belongs to the group of steroids.


Vitamin D doesn't like water, so it doesn't excreted through urine, but like other groups of fat-soluble vitamins, it is exreted through intestines.

It is believed that 85% of the total amount of vitamin D is produced under the influence of sunlight. 

Very little amounts of the vitamin D entering through food, and absorption depends on many factors. 

Therefore, vitamin D in addition to a daily exposure to sunlight, must be upgrading exclusively with supplements.

Vitamin D is resistant to high temperatures, drying, smoking, pasteurisation, sterilization. It is unstable in the presence of oxygen and in the light.

Points of interest related to vitamin D

- Eskimos, people who live at the North Pole living in conditions where there isn't much sunlight. Therefore, it would be considered to have a chronic deficit of vitamin D. However, this is not true, because their diet is exclusively based on fish, which is the best source of vitamin D.

- People with dark complexions (blacks) have several times higher requirement for vitamin D than people of white complexion. The reason for this lies in the synthesis of melanin, which is directly related to the synthesis of vitamin D.

- Vitamin D isn't produced in closed conditions. This means that if you sit at home, in the car or in a room where the windows are, you will not get vitamin D in this manner. The reason is that the sun's rays don't pass through glassess and don't affect the synthesis of vitamin D in the skin. Only external exposure to sun is the right way to produce vitamin D.

- Any sun protective cream blocks vitamin D synthesis in the skin by 95%

- Very small amounts of vitamins D crossing through breast milk into the baby's body. Milk of women is poor in vitamin D, which is why the needs of pregnant women and nursing mothers two times higher than in ordinary people.

- It isn't possible to overdose on vitamin D because the body only regulates the process of creating this vitamin from sunlight, getting as needed.

Sources of vitamin D in food

Plant food is very poor source of vitamin D. If necessary, tolerable amount of this vitamin can be found in cereals, orange juice and mushrooms. 

Food of animal origin which containing vitamin D are fatty fish (salmon, tuna, sardines, mackerel), then veal liver, cheese, egg yolk, milk in very small quantities.

The role of vitamin D in the body

1. Maintenance of calcium metabolism

Vitamin D is closely related to calcium and affects the proper growth and bone development in children. Lack of vitamin D will have a negative impact on the level of calcium and its absorption, and when the body lacks calcium, he pulls it from the bones, which negatively records on bone density. This disbalance can produce osteomalacia and rickets in children and osteoporosis in the elderly.

2. Maintenance of magnesium metabolism

Magnesium hasn't got impact on the absorption of vitamin D, but it is significant in the conversion of the inactive to the active form of vitamin D. Therefore, it is necessary to ingest magnesium in combination with vitamin D.

3. Prevents diabetes in children

4. The anticancer action of vitamin D in melanoma, breast, prostate, colon cancer

5. Prevents the formation of psoriasis and multiple sclerosis

The symptoms of vitamin D deficiency

- Rickets
- Osteomalacia
- Osteoporosis
- Fracture of bones
- Stroke and infarct
- Pain in the muscles and bones in the chronic form
- Weak immunity
- Chronic fatigue and exhaustion
- Depression
- Multiple sclerosis
- Diabetes
- Psoriasis
- Dementia
- Breast cancer, prostate cancer, and melanoma

Tip plus: Capsules with vitamin D is best absorbed when it entered with the food having a fat content in itself because vitamin D is one of the fat-soluble vitamins.


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