• Vitamin D
• Why do I need Vitamin D?
• Vitamin D Deficiency
• Can I Have Too Much Vitamin D?

What is Vitamin D?

Vitamins are nutrients that the body needs to function properly. Vitamin D, which strengthens bones, muscles and teeth, is a fat-soluble vitamin that can be stored in the body until needed.

In other words, vitamin D can be obtained naturally in the human body through exposure to sunlight or through the ingestion of specific food sources.

Vitamin D2 and Vitamin D3

The most common forms are D2 and D3. D2 occurs naturally in yeast, whereas D3 is produced by lanolin and is synthesized in the skin upon exposure to UV light.

In regards to the effectiveness, Michael F. Holick et al. recently observed that vitamin D2 and vitamin D3 were equally effective in maintaining blood levels of 25 (OH)D., although there have been some studies suggesting that vitamin D2 is less effective in maintaining serum 25 (OH)D levels. Thus, with this new information, it appears that vitamin D2 is equally effective as vitamin D3 in maintaining 25 (OH)D levels.

Reference: Holick et al. 2007: Vitamin D2 is as effective as Vitamin D3 in maintaining circulating concentrations of 25-hydroxyvitamin D. Journal Clinical Endocrinology Metabolism.