Wednesday, April 15, 2020

Vitamin D : Sources, Functions In Our Body, Daily Requirement, Deficiency Symptoms And Hypervitaminosis Of Vitamin D

Vitamin D : Sources, Functions In Our Body, Daily Requirement, Deficiency Symptoms And Hypervitaminosis Of Vitamin D

Vitamin D deficiency Rickets
Vitamin D


Vitamin D is a fat soluble vitamin that plays a very important role in human body. Vitamin D is essential for bone health. Research suggests that it may have other benefits too, such as protecting against colds and fighting depression. Vitamin D is called as Antirachitic factor as it prevents 'Rickets'. It is found that there are six types of Vitamin D. The nutritionally important forms of Vitamin D in human are Calciferol (Vitamin D2) and Cholecalciferol (Vitamin D3).

Calciferol may be derived by irradiation of the plant sterol, ergosterol.

Cholecalciferol is the naturally occurring (performed) Vitamin D which is found in animal fats and fish liver oils. It is also derived from exposure to Ultra violet (UV) rays of the sunlight which convert the cholesterol in the skin to Vitamin D. Vitamin D stored largely in the fat depots.


Sources Of Vitamin D

Vitamin D is unique as it is derived both from Sunlight and Foods.


  • Vitamin D from Sunlight :


Our body has the amazing mechanism to creat Vitamin D from direct sunlight on our skin when we are outdoors. Vitamin D is synthesized by the body by the action of UV rays of Sunlight on 7-dehydrocholesterol, Which is stored in large aboundance in the skin. But excessive exposure to UV rays is critical, this can be filtered off by air polution. Dark-skinned races such as Negros, also suffer from this disadvantage because black skin (due to presence of Melanin) can filtered off upto 95% of UV rays. These people of African, African-Caribbean or South-Asian origin will need to spend longer in the sun to produce the same amount of vitamin D as someone with lighter skin. But it is not known exactly how much time is needed to be in the sun to meet the daily requirement of Vitamin D.
  • Vitamin D from Foods :


  1. Mushroom : Just like human, some species of mushrooms have the capacity to produce Vitamin D when exposed to Ultra violet light. In 100 grams of Mushrooms of serving, the quantity of Vitamin D is 470 - 700 IU.
  2. Orange : Orange is a good source of Vitamin D. One cup of Orange juice have approximately 140 IU of Vitamin D
  3. Cereals : Cereals like Wheat, Cornflakes, Dalia, Ragi, Maize also has a good quantity of Vitamin D.
  4. Soya Milk : It is easily available in the every local market in canned form or otherwise, you can easily make it at home. For preparing it, soak milk overnight then grind it well and then filter the mixture. One cup of Soya Milk has 110 - 125 IU of Vitamin D.
  5. Curd : Card is also a good source of vitamin D. But make sure milk used at the time of curd preparation should be fortified with Vitamin D. One cup of 100 grams Curd has 90 - 100 IU of Vitamin D.
  6. Egg Yolk : One yellow portion of egg i.e. Egg Yolk contains Vitamin D. In one egg yolk has 40 - 50 IU of Vitamin D.
  7. Cod Liver Oil : This is oil extracted from the liver of the cod fish and rich in Vitamin D. It is available in market in the form of capsule. It also contains omega 3 fatty acids.
  8. Salmon Fish : It is a party fish and great source of Vitamin D. Quantity of Vitamin D is on an average 450 IU per 100 grams of serving.
  9. Sardine Fish : In case of Sardine Fish, quantity of Vitamin D per 100 grams of serving is 45 IU.
  10. Canned Tuna : Canned tuna contents 268 IU of Vitamin D per serving. But it contains significant quantity of poisonous methylmercury. So it is recommended to intake it in minimum limit.
  11. Cow's Milk : Cow's milk is a good source of many nutrients, including Calcium, Phosphorus and Vitamin D. It usually contains about 45 - 55 IU of Vitamin D per 100 ml of milk.

Functions of Vitamin D :


Vitamin D is an important vitamin required to maintain healthy life. Vitamin D plays several critical roles in our body, such as–


  1. Vitamin D promotes intestinal absorption of Calcium and Phosphorus to maintain bone health.
  2. Vitamin D stimulates the mineralization of bones to prevent osteoporosis.
  3. Vitamin D helps in the growth of teeth.
  4. Vitamin D has also some importance to control the functions of Parathyroid gland.
  5. Vitamin D has a major role to boost immune health as it activates white blood cells to fight against foreign bodies.
  6. Vitamin D is necessary for the proper functioning of Kidneys.
  7. Vitamin D is also required to reduce the risk of cardiovascular disorders.
  8. Vitamin D helps to boost cognitive health. Vitamin D3 regulates the enzyme that converts amino acid trypsin to serotonin. Serotonin is a neuro-transmitter which affects our mood and brain development.
  9. Vitamin D is also needed for proper muscle strength.
  10. Vitamin D (mainly Cholecalciferol) also helps in maintaining healthy sleep and prevent mood disorders.


Daily Requirement of Vitamin D :

According to the Institute of Medicine (IOM) of the National Academy of Science, the recommended dietary allowance (RDA) for Vitamin D is 600 IU per individuals aged from 1 year to 70 years. For people aged 71+ year the value of RDA is 800 IU.

However, Indian Council of Medical Research (ICMR) said that is a tropical country like India, Bangladesh, Pakistan, under minimum exposure to sunlight, a specific recommendation of a daily supplements of 400 IU is suggested.


Deficiency Symptoms of Vitamin D :

Due to insufficiency of vitamin D, a large amount of calcium and phosphorus is released from the body. Therefore, the amount of calcium and phosphorus in the blood has been decreased and it causes Rickets in children and Osteomalacia in adults.


Rickets : Deficiency of vitamin D leads to Rickets, which is usually observed in young children between the age of six months and two years. There is reduced calcification of growing bones. Rickets is characterized by growth failure, bone deformity, muscular hypotonia, tetany and convulsions due to hypocalcaemia. The bony deformities include checked legs, deformed pelvis, pigeon chest, Harrison's sulcus, ticket risau, kyphoscoliosis, etc.



Osteomalacia : Due to deficiency of vitamin D, a large amount of calcium and phosphorus is released from the body and causes low density of calcium in the plasma. Due to this, bone begins to decay.
In adults, Vitamin D deficiency during long period may result in osteomalacia which occurs mainly in women, especially during pregnancy and lactation when requirements of Vitamin D are increased.
Vitamin D insufficiency also leads to secondary hyperparathyroidism that causes increased bone loss, osteopenia, osteoporosis, and increased fracture risk.

In case of severe Vitamin D deficiency, it can cause myopathy, which can cause muscle weakness and pain.

Due to deficiency of Vitamin D, you may feel fatigue and Tiredness.

A depressed mood may also be a sign of Vitamin D deficiency, particularly in older adults.

Deficiency of Vitamin D may cause in slow healing of wounds after surgery or injury.


Ill Effects Due To Hypervitaminosis Of Vitamin D :

Vitamin D is necessary for our good health but more than what is necessary is not necessarily good. Hypervitaminosis of Vitamin D is a rare case but potentially serious condition. It occurs when you take in take in too much Vitamin D. It usually the results of taking high-dose Vitamin D supplements.

The abnormalities due to excessive amount of Vitamin D in the body are as follows –
  1. Hypervitaminosis of Vitamin D can cause excessive intestinal absorption of calcium and phosphorus; and calcium levels in the blood will rise. This can lead to a condition called hypercalcemia or hypercalcaemia. Due to this, calcium will be stored in kidney, heart and other parts of our body.
  2. Weight loss
  3. Nausea
  4. Dizziness


*Read about : Vitamin A : Sources, Functions in Our Body, Daily Requirement, Deficiency Symptoms, Hypervitaminosis of Vitamin A

*Read about : Definition of Vitamin, Types of Vitamins, Characteristics of Vitamin, Provitamin and Antivitamin

No comments:

Post a Comment