Yeah. This is a big problem for people with serious and complicated health issues. They are all too often told "It must be in your head" the subtext being "If it were real, I, a super smart doctor type, would be able to figure it out already." It's ugly stuff and it ruins lives.
Also, the lady was prescribed vitamin D and then took it without adjusting the dosage or having a follow-up about it for 5 years. This is a big problem as well. Doctors all too often don't follow up with patients and this is probably in part because of our issues in the US with how we pay for stuff and so on. But it was also a problem for some things when I was a military wife and could see a doctor for free.
I am a writer by trade and I have a serious medical condition. I'm glad to see this piece and I'm glad to see Deva Boone posting on HN, but I will suggest that statements like "Vitamin D is a medication" don't constitute good communication.
The latter part of the piece makes it clear what is intended by that, but it's not currently classified as a medication and I think it is generally more helpful to try to educate people that "life is chemistry" and there is no clear cut demarcation between "drugs" and "not drugs." Sometimes the difference boils down to dosage.
There are lots of things available in small quantities in food items that are "drugs" if you take a large enough amount in one shot and are "drugs" if prescribed in pill form that are "food" when part of your diet. And we need to get a lot savvier about things like that.
Hopefully, this is taken as helpful feedback and not an ugly attack. It is intended as the former and not the latter.