THE vitamin D is very important and has, among its functions, a role in the metabolism of the calcium. However, its benefits go beyond, being important, for example, in maintenance of the functioning of the Imune system.THE Vitamin D can be obtained through the ingestion of foods of animal and vegetable origin, in addition to being produced in our body, at the level of skin, by the action of ultraviolet radiation. His disability is related to bone problems.
Read too: Importance of vitamins - fat-soluble, hypo-soluble, and in food
What is Vitamin D?
vitamin from one term adopted to refer to a molecule that has four cholesterol rings. Despite being known as a vitamin, this nutrient Organic is quite different from other substances of this type, since it is produced in our body and not only obtained in our food. The substance, therefore, can be considered a hormone.
Vitamin D is found under two ways distinct, which are biologically equivalent:
Ergocalciferol or Vitamin D2: it is a form found in plants and fungi. It can be achieved in the diet, being absorbed in the small intestine.
Cholecalciferol or Vitamin D3: is a form found in animal sources. Furthermore, it is synthesized in our skin by the action of ultraviolet B (UVB) rays. These rays, in contact with keratinocytes and fibroblasts, convert 7-dehydrocholesterol into pre-vitamin D3 and, later, into vitamin D3. A curious fact is that black-skinned people have a certain limitation to the penetration of ultraviolet rays, thus, a lower production of vitamin D may occur in them.
Both forms of vitamin D, after ingestion or formation in the skin, are in inactive form, and, to become active, need to go through two hydroxylation processes. The first takes place in the liver, and the second occurs in the kidneys. It is in this last organ that the active form will take place.
Read too: B complex vitamins - definition, function and list
Functions of Vitamin D in the Body
Vitamin D plays an important role in the proper functioning of our bodies. Undoubtedly, one of the main functions assigned to her is her role in the calcium metabolism and bone formation. However, vitamin D is also involved in other physiological processes, and its deficiency is related, for example, to the development of diabetes mellitus type 1, food allergy, neoplasms, between others. Vitamin D is also an important modulator of our immune system.
Vitamin D Deficiency
Vitamin D deficiency is a relatively common situation in the population and can present as causes: inadequate sun exposure, malabsorption syndromes, obesity, increased skin pigmentation, and use of some medications.
It is noteworthy that there is a lot of discussion about what would be the optimal level of vitamin D in the body. According to the publication “Official Positioning of the Brazilian Society of Clinical Pathology/Laboratory Medicine and of the Brazilian Society of Endocrinology and Metabolism”, the desirable value for a healthy population up to 60 years of age is above in 20 ng/ml
Vitamin D deficiency is related to a decreased calcium absorption, triggering a reduction in bone mineralization. It can cause rickets in children and osteomalacia in adolescents and adults. O rickets can cause short stature, reduced growth and skeletal deformities. THE osteomalacia, in turn, can be asymptomatic, but can also cause bone pain and muscle weakness.
According to the Brazilian Society of Endocrinology and Metabolism, generalized vitamin D supplementation is not indicated. Also according to society, the benefits of treatment with this vitamin are more evident in populations at risk of developing its disability, such as the elderly and people with malabsorption syndromes intestinal.
It is noteworthy that, in excess, vitamin D can cause intoxication. Thus, when taking the supplement, it is essential to follow the medical recommendations, in addition, it is important that self-medication never occurs. One of the consequences of overuse of this vitamin is the hypercalcemia, which is an increase in calcium levels in the blood responsible for triggering, for example, loss of kidney function.
Read more:Importance of calcium in the body, especially in the development of bones and teeth
Vitamin D sources
Vitamin D can be obtained through food and skin synthesis. Food represents only a small portion of the total amount of vitamin D in our body, a large part of which is synthesized by the skin. It is estimated that, practically, 90% of the body's vitamin D is acquired by cutaneous synthesis.
Therefore, we must expose ourselves to the sun to ensure a greater production of vitamin D. However, it is necessary to be careful, avoiding, for example, exposure between 10 am and 4 pm. The recommendation is exposure to the sun for at least 20 minutes a day, in the early morning or late afternoon.
With regard to food sources, we can cite as vitamin D-rich foods: o cod liver oil, sardines, salmon, beef liver and egg yolks. It is important to point out that, although diet is not the best way to get vitamin D, it has a great importance for those people who live in temperate climates and for the elderly, for example.
By Vanessa Sardinha dos Santos
Biology teacher