What is the process of vitamin D synthesis?

In the presence of sunlight, a form of vitamin D3 called cholecalciferol is synthesized from a derivative of the steroid cholesterol in the skin. The liver converts cholecalciferol to calcidiol, which is then converted to calcitriol (the active chemical form of the vitamin) in the kidneys.

How is vitamin D synthesized and utilized by the body?

A unique aspect of vitamin D as a nutrient is that it can be synthesized by the human body through the action of sunlight. These dual sources of vitamin D make it challenging to develop dietary reference intake values. Vitamin D, also known as calciferol, comprises a group of fat-soluble seco-sterols.

What activates synthesis of vitamin D?

Vitamin D from the diet, or from skin synthesis, is biologically inactive. It is activated by two protein enzyme hydroxylation steps, the first in the liver and the second in the kidneys.

How is vitamin D processed in the body?

After vitamin D is absorbed through the skin or acquired from food or supplements, it gets stored in the body’s fat cells. Here it remains inactive until it’s needed. Through a process called hydroxylation, the liver and kidneys turn the stored vitamin D into the active form the body needs (called calcitriol).

How is vitamin D 3 synthesized in the body?

Vitamin D Synthesis. In the presence of sunlight, a form of vitamin D 3 called cholecalciferol is synthesized from a derivative of the steroid cholesterol in the skin. The liver converts cholecalciferol to calcidiol, which is then converted to calcitriol (the active chemical form of the vitamin) in the kidneys.

What are the factors that affect vitamin D synthesis?

Season, time of day, length of day, cloud cover, smog, skin melanin content, and sunscreen are among the factors that affect UV radiation exposure and vitamin D synthesis [ 1 ]. Perhaps surprisingly, geographic latitude does not consistently predict average serum 25 (OH)D levels in a population.

How does vitamin D work in the skin?

The skin is unique in being not only the source of vitamin D for the body but also in being capable of responding to the active metabolite of vitamin D, 1,25(OH) 2D. Both 1,25(OH) 2D and its receptor (VDR) play essential roles in the skin.

What are the different forms of vitamin D?

There are two forms of vitamin D: vitamin D 2 (ergocalciferol), which comes from irradiation of the yeast and plant sterol; ergosterol; and vitamin D 3 (cholecalciferol) which is obtained from oily fish and by skin synthesis.