What is the Difference Between Cholecalciferol and Ergocalciferol?

Cholecalciferol and ergocalciferol are two forms of vitamin D that differ in their sources, structure, and efficacy in raising vitamin D levels in the body. Here are the main differences between them:

1. Sources: Cholecalciferol (vitamin D3) is found in animal sources such as oily fish, liver, egg yolk, and butter, as well as dietary supplements. Ergocalciferol (vitamin D2) is obtained from plant sources or dietary supplements derived from irradiated fungi.
2. Structure: Cholecalciferol is produced by synthesis in the skin with ultraviolet B light exposure, while ergocalciferol is produced from ergosterol found in plants and fungi when they are exposed to UV radiation.
3. Efficacy: Although both cholecalciferol and ergocalciferol are absorbed equally well, research shows that cholecalciferol is more effective in raising and maintaining vitamin D levels in the body. For example, a study found that a single dose of vitamin D3 was nearly twice as effective as an equal amount of vitamin D2.
4. Metabolism: The liver metabolizes vitamin D2 into 25-hydroxyvitamin D2 and vitamin D3 into 25-hydroxyvitamin D3. These two compounds are collectively known as calcifediol, which is the main circulating form of vitamin D in the body. Vitamin D2 seems to yield less calcifediol than an equal amount of vitamin D3.

In conclusion, while both cholecalciferol and ergocalciferol are forms of vitamin D, they differ in their sources, structure, and efficacy. Cholecalciferol is more effective in raising and maintaining vitamin D levels in the body, making it a better choice for supplementation.

Comparative Table: Cholecalciferol vs Ergocalciferol

Cholecalciferol and ergocalciferol are two important secosteroid compounds, also known as vitamin D3 and vitamin D2, respectively. Here is a table highlighting the differences between cholecalciferol and ergocalciferol:

Both cholecalciferol and ergocalciferol are transported by vitamin D-binding protein in the blood to the liver, where they are converted by liver 25-hydroxylase. They are then converted into their active forms, 1,25-dihydroxyvitamin D3 for cholecalciferol and 1,25-dihydroxyergocalciferol for ergocalciferol.