[spfzero]

And a large proportion of people are deficient, probably most people actually. I’d rather he advised all people to get outside, do things outside under the sun and let your skin do its work, making all of the things it does, including D3.

[Loulybob]

For a lot of people who live in the Northern Hemisphere who are about to go into a period of long, dark nights during winter, your advice of "get outside, do things outside under the sun and let your skin do its work" is not really as helpful as taking vitamin D supplements.