Difference between vitamin d and vitamin d3
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Differences Between Vitamin D and Vitamin D3
Introduction to Vitamin D and Vitamin D3
Vitamin D is a crucial nutrient for maintaining bone health and calcium homeostasis. It exists in two primary forms: Vitamin D2 (ergocalciferol) and Vitamin D3 (cholecalciferol). Both forms are used in dietary supplements and fortified foods, but they have different origins and potencies.
Sources and Production
Vitamin D2 (Ergocalciferol)
Vitamin D2 is derived from plant sources and fungi. It is produced by the ultraviolet irradiation of ergosterol, a compound found in fungi and yeast .
Vitamin D3 (Cholecalciferol)
Vitamin D3 is synthesized in the skin of humans and animals when exposed to ultraviolet B (UVB) rays from sunlight. It can also be obtained from animal-based foods and supplements .
Potency and Efficacy
Comparative Potency
Research consistently shows that Vitamin D3 is more potent than Vitamin D2 in raising and maintaining serum 25-hydroxyvitamin D [25(OH)D] levels. A study demonstrated that Vitamin D3 is approximately 87% more effective than Vitamin D2 in increasing serum 25(OH)D concentrations . Another meta-analysis confirmed that Vitamin D3 significantly raises serum 25(OH)D levels more than Vitamin D2, especially when administered as a bolus dose .
Bioavailability and Storage
Vitamin D3 not only raises serum 25(OH)D levels more effectively but also results in greater storage of the vitamin in body fat compared to Vitamin D2. This suggests that Vitamin D3 has a longer-lasting effect in the body 14.
Physiological Effects
Bone Health and Calcium Absorption
Both forms of Vitamin D are crucial for calcium absorption and bone health. However, due to its higher potency, Vitamin D3 is generally preferred for treating and preventing Vitamin D deficiency 14.
Immune System
Vitamin D3 and D2 also have different effects on the immune system. Vitamin D3 has been shown to down-regulate genes associated with the innate and adaptive immune systems, potentially making the immune system more tolerogenic. In contrast, Vitamin D2 does not have the same effect on gene expression related to immune responses .
Metabolic Pathways
Conversion to Active Forms
Both Vitamin D2 and D3 are converted in the liver to 25-hydroxyvitamin D, the major circulating form used to assess Vitamin D status. They are further hydroxylated in the kidneys to form the active hormone 1α,25-dihydroxyvitamin D. However, Vitamin D3 is more efficiently converted to its active form, contributing to its higher efficacy 68.
Inactivation
The inactivation of both forms involves similar metabolic pathways, but Vitamin D3 metabolites are more stable and have a longer half-life, which further supports its superior efficacy .
Conclusion
In summary, while both Vitamin D2 and D3 are important for health, Vitamin D3 is more potent and effective in raising and maintaining serum 25(OH)D levels. It also has a more significant impact on the immune system and is more efficiently metabolized and stored in the body. Therefore, Vitamin D3 is generally the preferred form for supplementation and treatment of Vitamin D deficiency.
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