[spurgu]

I know very little about nutrition but have wondered whether taking supplements actually help, or if it's the process that _creates_ those vitamins that's actually important/healthy.

Like in your example, being exposed to sunlight starts a process in our body that's healthy for our bodies, and vitamin D is just a by-product... and taking it as supplements wouldn't really do anything as we're missing the process.

As I said I have no idea what I'm talking about.

[heavyset_go]

> if it's the process that _creates_ those vitamins that's actually important/healthy.

By definition, vitamins are substances needed by an organism that it can't create itself, and must be obtained in its diet.

[jwilk]

Vitamin D is technically not a vitamin:

https://academic.oup.com/ajcn/article/88/2/491S/4649916#1112...

[dehrmann]

Vitamin D is arguably not a vitamin because we produce it when exposed to sunlight and it's actually a hormone. I guess that makes sunlight the vitamin.

[0_____0]

vit D is an exception here, iirc it's the only 'vitamin' that doesn't fit those criteria

[rossdavidh]

It could easily be some of both, in which case a supplement is not necessarily worthless, but not as good as sunlight (and the exercise and stress reduction that often goes with it).