Killery , Rockleo posted everything we know about Vit D,
Let me just add couple things about our GI system..,
With healthy gut with good bacteria , it is easier to get higher blood level of Vit D , some feel it is good to take Vit D with probiotic,
All together our GI system is very interesting , has so many brain like neurons and neurotransmitters that it is call our second brain..
Gut may influence our mood , decisions making etc..
And when people saying ... " my gut feeling "...they really accurate :))
And gut is healthier having 'Good " germs ..
It is important not only for Vit D , but for general well being..
This is why for many years now many physicians feel that it is important to take probiotics.
IMO only...