Yes, Uny, the kidneys are involved...Re: D3 Deficient This Time of Year?
...in Vitamin D production.
Here's a little chart I found:
How our bodies convert sunlight into Vitaminj D- image by www.healthyfellow.com
So you can see that the liver converts sunlight into usable Vitamin D and stores it there for future use. The kidneys balance calcium. As Uny mentioned, in order for Vitamin D to be assimilated properly, our livers and kidneys must be in good shape. So it all works together.
Oh- you *can* get Vitamin D3 from, in particular, fish oil and salmon. Please do your research. Schulze, Christopher, and so many other great natural healers are/have been adament vegetarians, and as Uny listed, there are effective plant sources for dietary Vitamin D.
Sometimes I just stand amazed at how beautifully designed our bodies are...
Wings