The discovery of vitamins had been made in 1922 by an American scientist Elmer Mc Cullum.

Initially, it was supposed that Rickets [a disease caused by a deficiency of vitamin d] was caused by

Deficiency of vitamin A, later on, the fact was visualized by mc Cullum that Rickets in dogs was treatable by modified cod liver oil without containing vitamin A. then he named that newly discovered substance vitamin D The name ‘vitamin D’ was given because it was the vitamin which was named in 4th place in naming pattern


Vitamin D is a fat-soluble sec steroid.

The mode of functioning of vitamin D is to increase the absorption of calcium, phosphate and magnesium in human intestines.

Vitamin D is synthesized in the lower layer of the epidermis of human skin by a chemical reaction with the help of UVB radiations after exposure to sunlight and the final result of the compound synthesized is called cholecalciferol.

Vitamin D can also be obtained through diet such as fatty fish flesh, cow’s milk   

breakfast cereals and mushrooms.

But the vitamin D obtained either from sunlight exposure or dietary supplements is in the biologically inactive form.

It is activated by protein enzymes in two steps:

The first step takes place inside the liver and the other inside the kidney.

The process of synthesis of active vitamin D is called “hydroxylation”

The biologically active form of vitamin D is popularly known as “Calciferol”. Calciferol is significantly considered to play a vital role in the absorption of calcium and phosphate resulting in the remodelling and proper growth of bones.


Vitamin D exists in five forms of VI tamers.

VITAMIN D1: it is a combination of ergo calciferol and lumisterol.

VITAMIN D2: ergo calciferol.

VITAMIN D3: cholecalciferol:

VITAMIN D4: dihydro ergo calciferole.

VITAMIN D5: sito calceferole 

Despite the several VI tamers, its two major VI tamers are D2 and D3.

Vitamin D plays a vital role in maintaining the skeletal calcium balance by absorbing the calcium inside the intestines and maintaining the calcium and phosphorus levels which are further used in the formation and remodelling of bone structures.

It further helps in the proper functioning of the parathyroid gland which is responsible for the maintenance of serum calcium levels.


Around the globe around one billion people are found to be deficient in vitamin D.

Vitamin D deficiency is mainly caused by taking a diet which is insufficient in vitamin

and with very less exposure to sunlight.

Vitamin D deficiency affects children as well as adults.

Its deficiency results in crippled mineralization in bones and damages the bones which further results in bone-softening diseases.

Bone softening in children is called ‘RICKETS’ and in adults, it is termed ‘OSTEOMALACIA and OSTEOPOROSIS’.


Rickets is an infancy disease characterized by hampered growth of bones further adding to this weakness, softening and deformation of major bones.

The long bones start to bend and bow as soon as children are starting to walk.

Rickets mainly appears between 3 and 18 months of age.

Rickets may be transferred from mother to child before birth.


Osteomalacia is a disease in adults which resulted due to a deficiency of vitamin d.

osteomalacia is characterized by

  • Bone fragility
  • Bowing of legs
  • Softening of bones
  • Bending of spine
  • Weakness of proximal muscle.
  • Fracture of bones.

Osteoporosis is a chronic form of calcium and vitamin d deficiency.

It is characterized by a significant reduction of bone mineral density and an increase in bone fragility which leads to bone fractures.


As we know vitamin d is synthesized under the skin with the help of sunlight. The dark skin people contain excess melanin in the skin which is supposed to reduce the process of vitamin d synthesis from UVB rays under the skin.


  1. Bone well-being:

In children, vitamin d along with supplementary calcium is a very decent combination to enhance the children’s bone health as their bones are always in process of continuous growth.

Whereas in older people osteoporosis can be prevented by providing vitamin d along with calcium in older people but the risk of kidney and stomach issues can increase.


  Some studies found that a low level of vitamin d may associate with several types of cancers especially colorectal cancer.


Vitamin d supplementations do not lower blood pressure and they can’t prevent the risk of myocardial infarction, stroke, ischemic heart disease or cerebrovascular diseases.


Vitamin d deficiency has been found to be a cause of increased risk or increasing severity of some viral infections like covid19 and HIV.

The risk factors for tuberculosis, are supposed to be increased in patients suffering from vitamin d deficiency.

The low-dose supplementation of vitamin d may decrease the risk of having respiratory tract infections, especially in young children.


In people suffering from asthma, though vitamin d supplementation does not directly decrease the symptoms of asthmatic attack use of vitamin d in asthmatic people might be helpful in reducing the excessive use of steroids. [ steroids are used to reduce the frequency of mild to moderate asthmatic  attacks.]


A study shows that people having low levels of vitamin d might develop two major inflammatory bowel diseases.

  • Ulcerative colitis.
  • Crohn’s disease.

 Supplementations of vitamin d can significantly reduce the risk of type 2 diabetes mellitus.

  • ADHA:

An observational study shows that children suffering from ADHD are found to be having low levels of vitamin d.

Some trials of vitamin d supplementations resulted in improving ADHD-related symptoms like hyperactivity and impulsivity.


Low levels of vitamin d have a slight impact on cognitive impairment hence resulting in Alzheimer’s disease.


Peoples suffering from acute schizophrenic attack represents the descent results of consuming vitamin d.


Pre-eclampsia, SFGA, and gestational diabetes are mainly associated with a deficiency of vitamin d.


Daily dietary supplementation of vitamin D in the U.S is as follows:

  • Infants aged between 0 to 12 months: 400 I.U per day.
  • One year to 70 years: 600 I.U per day.
  • Above 70 years: 800 I.U per day.
  • Pregnant or lactating mothers: 600 I.U per day.


  • Beef liver, braised, cooked.
  • Fish liver oil/ cod liver oil.
  • Cooked egg yolk.
  • Thalli [lichen]
  • Caledonia arbuscular.
  • Raw mushroom species such as Portobello and crimini.
  • Salmon [pink].
  • Mackerel.
  • Sardines.


Although vitamin d toxicity is very rare, however according to some studies the tolerable intake level of vitamin d is 4000I.U per day for adults.

  • Overdose of vitamin d causes hyperkalemia.

Hyperkalemia can’t be getting treated.

Symptoms of hyperkalemia may include an increase in micturition and thirst.

In people suffering from hyperkalemia, the excess present in the body gets deposited in soft tissues and organs like the liver, kidney and heart. And result in damage to the organ.

  • Anorexia.
  • Polyuria.
  • Insomnia.
  • Polydipsia.
  • Weakness.
  • Nausea and vomiting.
  • Pruritus.
  • Nervousness.
  • Proteinuria.
  • Metastatic calcification.
  • Toxicity of vitamin d can be treated simply by discontinuing the supplementation of vitamin d and by restricting the calcium intake.

But renal damage can be irreversible.

Leave a Reply

Your email address will not be published. Required fields are marked *