Vitamin D cycle and calcium control

Vitamin D cycle and calcium control

Vitamin D

Vitamin D is the vitamin known as the sun’s vitamin. The main source of the sun is the body’s exposure to the body until the body produces this vitamin, by exposing the skin to ultraviolet light from the sun, it converts the cholesterol found in the skin through a series of biological processes to Vitamin D. The exposure of hands and feet to the sun from five to ten minutes, two to three times a week long enough to provide the body need of vitamin D, in addition to the availability of limited quantities in some foods.

Vitamin D and calcium

Vitamin D increases the level of calcium in the blood by:

  • Increase the absorption of calcium from the intestines.
  • Reduce calcium loss through urine by increasing calcium re-absorption in the kidneys.
The lack of calcium in the blood stimulates the secretion of thyroid glands to the thyroid gland, which increases the level of calcium in the blood by analyzing calcium from the bones. When calcium is increased in the blood, calcitonin, which is produced by calcium, Thyroid to reduce the proportion of calcium in the blood by increasing the deposition in the bones.

Vitamin D cycle in the human body

  • Vitamin D is a fat-soluble vitamin, so the intestine absorbs it with other fats when it is obtained from food. The vitamin then travels inside the cells that transport through the blood stream to the liver.
  • Vitamin D is also made in the skin by direct exposure to the sun as follows:
    • The skin has a substance called 7-dehydrocholesterol.
    • When the skin is exposed to ultraviolet light, the substance (7-dihydroculistrol) is transformed into cholecalciferol.
    • Then the substance (kolkalsvirol) through the blood stream until it reaches the liver.
    • The liver contains an enzyme (25-alpha hydroxylase), which stimulates the process of turning the substance (kolksalciferol) to 25-hydroxycholecalciferol (25-hydroxycholecalciferol).
    • The substance (25-hydroxycalciferol) is transferred to the kidneys.
    • The kidneys contain an enzyme (1-alpha hydroxylase), which stimulates the transformation of 25-hydroxycalciferol into 1,25-dihydroxycolicciferol, called vitamin D3 or calcitriol.

The Importance of Vitamin D

Vitamin D, which is metabolized in the body, is called 1,25-dihydroxycolicciferol (English: 1,25 (OH (2D3)), where vitamin D enters many vital processes including:

  • Maintain the growth and development of healthy bones and teeth.
  • Maintain a balance of calcium and phosphorus metal in the body.
  • Inhibition of cancer cell growth.
  • Protect the body from various immune diseases.
  • Minimize the incidence of inflammation in the body.
  • It enters into the growth, division and differentiation of different body cells.

The body needs vitamin D

Recommended Dietary Allowances for vitamin D are sufficient to maintain healthy bone, teeth, and calcium metabolism in healthy people. This amount varies according to the age of the person as follows:

  • Infants aged 0-12 months need 400 IU.
  • Children aged 1 to 60 need 600 IUs

Sources of Vitamin D

There are very few foods that in nature contain vitamin D, fatty fish meat (such as salmon, tuna, mackerel), and fish liver oils are considered among the best sources, and there are low amounts of vitamin D in the liver, cheese , And egg yolk). Vitamin D can be obtained from fortified foods such as milk, butter and orange juice, and it should be written in the nutritional information of these foods that it is supported by vitamin D. Vitamin D can be obtained from supplements, but should not be taken without consulting your doctor. As for exposure to the sun, most people get a small amount of their needs of vitamin D through exposure to sunlight, for several reasons, including:

  • Clothing. Clothing can cover a large part of the body when exposed to direct sunlight.
  • Use sunscreen.

Vitamin D deficiency

Vitamin D deficiency appears in the form of rickets in children and in the form of osteoporosis
(Osteomalacia) in adults, and may lead to osteoporosis and fractures. Vitamin D deficiency is associated with a high incidence of cancer, Autoimmune diseases, Hypertension, and infectious diseases. The lack of adequate vitamin D intake is widespread throughout the world regardless of age, health status, and vitamin D deficiency is associated with a lack of calcium absorption and metabolism.

Vitamin D deficiency and risk of cancer:
Low levels of vitamin D in the body are closely associated with the risk of cancer and mortality, because vitamin D performs many processes that may slow or prevent cancer. These include:

  • Reduce the growth of cancer cells.
  • Stimulate the process of apoptosis, a natural process that occurs to the cells of the body to maintain the integrity of the body and the vital processes that occur within it.
  • To promote the cellular differentiation of cells within the body, a process of differentiation of cells into different types of specialized cells.
  • Reducing the process of angiogenesis of cancer cells, the process by which cancer cells begin to spread, through the production of food and energy for cancer cells through blood vessels.