Vitamin D3 (cholecalciferol) and vitamin D2 (ergocalciferol) belong to vitamin D. As a fat-soluble vitamin, VD is with anti-rickets effect. It is a general term for structurally similar sterol derivatives. Therefore, what we mean by vitamin D is not one substance but a group of structurally similar substances. Among them, vitamin D3 and vitamin D2, which play a role in human nutrition, have the same physiological role. But they also have many differences, and this article will introduce them to you.
Vitamin D2 vs. Vitamin D3
1. Definition:
Vitamin D2's chemical name is ergocalciferol, and ergocalciferol is an open-ring steroid formed by cleavage of chemical bonds of steroids under photochemical action.
Vitamin D3 is also known as cholecalciferol. The 7-dehydrocholesterol produced by dehydrogenation of cholesterol can be irradiated with ultraviolet light to form cholecalciferol. This means that the provitamin D of cholecalciferol is 7-dehydrocholesterol.
2. Physical and chemical properties:
The appearance and properties of vitamin D2 are odorless crystals. It has a density of 0.97 g/cm3, a melting point of 114-118 °C (lit.), a boiling point of 504.2ºC at 760 mmHg, a flash point of 218.2ºC, a refractive index of 1.53, and storage conditions of 2-8ºC.
The appearance and properties of vitamin D3 are crystalline. It has a density of 0.96 g/cm3, a melting point of 83-86 °C (lit.), a boiling point of 496.4ºC at 760 mmHg, a flash point of 214.2ºC, a refractive index of 1.507 (15ºC), stable at room temperature and pressure, and storage Conditions are 2-8ºC.
3. Source:
Vitamin D2, also known as ergocalciferol, is produced by ultraviolet radiation from ergosterol in plants. Plant-based foods such as grains, vegetables, and fruits contain little vitamin D2, and mushrooms contain relatively high amounts.
Vitamin D3 is converted from 7-dehydrocholesterol in human or animal epidermis and dermis cells through photochemical reaction by ultraviolet irradiation. The epidermis and skin tissue of most higher animals contain 7-dehydrocholesterol.
4. Biological activity
The biological activity of vitamin D3 is stronger than that of vitamin D2. Vitamin D3 increases and maintains serum 25(OH)D concentrations approximately 87% higher than vitamin D2, and vitamin D3 fat stores are 2-3 times higher than vitamin D2.
5. Risk of overdose
Excessive intake of vitamin D2 and vitamin D3 can lead to toxicity due to hypercalcemia.
But vitamin d2 is milder, so in an overdose, vitamin d2 is more tolerated and less risky than vitamin d3.
Vitamin D3 has vigorous activity, and excessive intake can easily lead to calcification of cartilage tissue.
Summary
Vitamin D2 and D3 are essential nutrients for maintaining human health, and play an essential role in regulating body metabolism and maintaining normal physiological functions. At present, it is believed that the biological effect of vitamin D3 is stronger than that of vitamin D2, so vitamin D3 is generally chosen as a supplement.