[ruszki]

Because there are other seasons, climate types, latitudes, skin colours, and there are a ton of people who rarely, if at all go outside, especially those who have panic, stress, or anxiety disorders.

Also, of course, there is a variability between people how much vitamin D they can produce, but we have no real clue about the causal connections there, but so far it seems that it’s way less important than other factors generally speaking, especially in the context of “many people”.

[talldatethrow]

Well I said many people because I'm not an encyclopedia... I just knew it was a lot which refutes your point.

So I looked it up, like you should have. In the US it's 40%. You're telling me 40% of people don't go outside for a few minutes??

If 40% of people have a vitamin D deficiency, I think you should change your recommendation for everyone other than people that get a lot of sun.