Supplements are not a public service. They are a gazillion dollar a year Industry. They make money when you buy supplements regardless of the price of one bottle.
But we are all deficient in vitamin D.
How do you know that?
Because this study said so.
And who paid for that study?
Um, the people who are selling Vitamin D.
Why does this not bother people?
And as for the argument that people in northern latitudes will always need supplementation. I seem to remember a bunch of folks a while back called the Vikings. They lived way up north and kicked some serious tail, all with no Vitamin D capsules.
I'm not now nor was I ever saying that vitamin D deficiency does not exist in some people some times. I'm just saying that is has been made a catch all self diagnosis for every conceivable malady. Most Vitamin D deficiency could easily be cured by people getting out from behind their computers and getting outside more often.