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Where is vitamin D.
Where is vitamin D.

Vitamin D

vitamins are essential nutrients for the human body , which are organic compounds found naturally in foods and needed by the body in simple quantities to carry out its natural functions, and thus the body cannot manufacture them or manufacture sufficient quantities of them to satisfy their needs, and thus it must obtain them from external sources, and their deficiency causes Specific symptoms.

vitamin D is taken under consideration among the fat-soluble vitamins and differs from other vitamins by the facility to manufacture it within the body through medium exposure to sunlight from a staple that the body makes from cholesterol, and it works as a steroid called dihydroxy.

Collie Calceverol (calcitriol), which plays an important role in bone health and balance of calcium within the body.

Daily needs for vitamin D

The following table shows the daily needs for vitamin D by age group: 

Upper bound micrograms / day
Daily requirement micrograms / day
Age group
Infants 0-6 months
Infants 6-12 months
Children 1-3 years
Children 4-8 years
5-50 years
51-70 years
71 years and over
Pregnant and lactating women

Where to find vitamin D.

  • Dietary supplements containing vitamin D .
  • Food sources aren't sufficient to get the requirements of vitamin D , and exposure to sunlight is important for the body to manufacture, as most studies have found that exposure to sunlight for 10 to fifteen minutes on sunny days two to 3 times every week is sufficient to supply the body with its vitamin D needs However, people with darker skin may have longer than exposure to the sun to urge their needs.
  • vitamin D is found in animal products, especially fish liver oil. it's also found in simple and ranging amounts in butter, cream, egg yolks, and liver. It also can be obtained from juices, breakfast cereals and margarine supported with it.
  • Breast milk, also as cow's milk, may be a weak source of vitamin D . Therefore milk is usually fortified with it. It must even be given to a toddler who is breastfeeding as a doctor's prescription.
  • And people who don't get enough sunlight should drink two cups of milk fortified with vitamin D daily.
  • Vitamin D is taken into account to be very stable because it isn't lost from food when exposed to heat or for long periods of storage. Volume 0%

Vitamin D functions within the body

  • vitamin D works mainly as a steroid and has protein-binding proteins within the blood, and works by its interaction with vitamin D receptors within the walls and intentions of cells, affecting the tactic of transcription of genes in several tissues, because it affects quite 50 genes, including the protein gene for calcium binding, which includes Its functions include the following:
  • The balance of calcium and phosphorus within the body, and these are considered the foremost prominent functions of vitamin D within the body because it stimulates the formation of the protein bound to calcium within the intestinal wall to increase the absorption of calcium, and it also helps within the absorption of calcium by stimulating the calcium channels to take in it.
  • vitamin D has a crucial role within the precipitation of minerals within the bones by maintaining their concentration within the blood. vitamin D also increases phosphorus absorption, because it reabsorbs calcium and phosphorous within the kidneys.
  • It maintains with the parathormone and calcitonin the extent of calcium within the blood. If the extent of calcium within the blood decreases, the parathormone rises, stimulating the withdrawal of calcium from the bones and thus the discharge of phosphorous within the urine, while if the extent of calcium within the blood rises, the calcitonin increases to spice up the speed of elimination Calcium within the urine, so vitamin D and calcium in sufficient quantities maintain normal levels of calcium within the blood and stop elevated parathormone and calcium loss from the bones.
  • The hormone calcitriol plays an important role within the differentiation of cells, their reproduction, and their growth naturally in many tissues that include the skin, muscles, parathyroid, system, brain, nervous system , cartilage, pancreas, reproductive organs, breast, and colon, and it prevents abnormal growth of cells and thus reduces the danger of cancer.
  • vitamin D plays an important role within the prevention of rheumatic diseases, which are autoimmune diseases.
  • It plays an important role within the metabolic processes within the muscles and affects its strength and contraction, and its muscle weakness, especially the center muscle, is weakened.
  • Some studies have found that the extent of calcitriol within the blood is inversely proportional to insulin resistance which it is a task in preventing type 2 diabetes.
  • Several recent studies suggest the role of vitamin D in regulating the work of the system after it found vitamin D receptors in its cells, where the imbalance within the system responses causes type 1 diabetes, sclerosis and inflammatory bowel diseases, and vitamin D regulates these responses. 
  • Recent research studies many new roles of vitamin D in tissues previously unknown to vitamin D.

Vitamin D absorption, transport and storage

50% of the vitamin D is absorbed with the fat by passively spreading to the cells of the intestine, which converts the fats into kilomicrons and introduces vitamin D with it, then it's absorbed into the systema lymphaticum then enters the plasma. As for vitamin D , which is formed within the skin, it enters the blood and moves to different tissues. The liver stores only alittle amount of vitamin D. 

vitamin D deficiency: 

vitamin D deficiency may be a common ill health that an outsized number of individuals are exposed to, and it causes a decrease within the formation of calcium-binding proteins within the intestine cells, which affects the absorption of calcium. Therefore, a vitamin D deficiency causes a calcium deficiency albeit ingested in quantities Enough. vitamin D deficiency causes rickets in children and osteomalacia in adults 2

Causes of a deficiency of vitamin D .

  • Not enough exposure to the sun, as happens in some countries that lack bright sunlight or due to a life-style that forestalls an individual from adequate exposure to sunlight.
  • Dark skin.
  • Breastfeeding breast milk without giving the baby vitamin D . supplements.
  • Some studies have found that obesity reduces the absorption of vitamin D , so if an individual relies on natural and fortified food sources instead of sun exposure, obesity can cause him to possess a deficiency of vitamin D .
  • Gastrointestinal diseases that cause poor digestion and absorption of fat also cause a deficiency in vitamin D . absorption

Symptoms of a vitamin D . deficiency

Rickets, a disease that happens thanks to insufficient amounts of minerals to settle within the bones during the expansion stage, and is caused by a scarcity of vitamin D because it are often caused by a scarcity of calcium and a scarcity of phosphorous, and its symptoms include:

  • Distortions in bone structure and shape, where the bones become weak and can't carry weight or withstand normal pressures, leading to curvature within the bones of the legs at the age when the kid begins to face and walk, and also produces bumps within the sort of rosary within the bones of the chest, and therefore the emergence of bones Chest or so-called pigeon chest, and anterior skull bone protrusion.
  • Carpal and ankle enlargement is caused by the failure of those areas to deposit metals, and thus continues to grow.
  • Bone pain.
  • Muscle suppleness.
  • Muscle spasms (constriction and protracted spasm) thanks to a scarcity of calcium.
  • High level of alkaline phosphatase within the blood thanks to its release from the cells destroying the bone cells.
  • In children with vitamin D deficiency, the looks of teeth is delayed, and abnormalities and weakness of the teeth can also appear.


This disease causes a decrease in bone density and therefore the appearance of quasi-fractures within the bones, especially within the spine, femur, and humerus, with muscle weakness, and this disease raises the danger of fractures, especially within the bones of the pelvis and wrist, and it particularly affects women that suffer from a scarcity of calcium and insufficient exposure to sunlight, it's going to cause curvature within the feet and curvature within the back.

Other symptoms of vitamin D 

  • deficiency were found to possess a relationship between vitamin D and depression, and vitamin D supplements were also found to assist treat people with depression who have a deficiency in it.

  • Some studies have found a relationship between vitamin D deficiency and a rise in body fat accumulation, which contributes to obesity and weight gain.
  • Research has found that a scarcity of vitamin D increases the susceptibility of the body to infections and respiratory viruses and bacteria, because it features a role within the occurrence of asthma and should also play a task in its treatment.

Toxicity of vitamin D .

It causes an excessive intake of vitamin D i.e. intake of amounts exceeding the upper limit daily. Toxicity. This toxicity results from consuming vitamin D supplements and not from exposure to the sun or its intake from its natural sources. the danger increases with a high level of calcium and phosphorus within the blood, which leads to:

  • Soft tissues like the kidneys, heart, lungs, and eardrum within the ear can cause deafness (deafness). Symptoms include headache and nausea.
  • It may cause kidney stones and calcification within the arterial walls. it's going to present a high risk within the arteries of the guts and lungs which will cause death.
  • Vitamin D toxicity in infants causes gastrointestinal upset, weakening of the bones, and developmental delay, so vitamin D supplements should be taken only as a doctor and with care and that they should be kept out of the reach of youngsters .