It's a fairly common reference, the whole "Vitamin C to help calm somebody down from their trip" thing. I don't know that it's literally been proven effective or not, but even the Woodstock movie makes mention of Orange slices being available at the first-aid tents so at the very least the reference has been around since the 60s, and I'm quite sure even longer than that.

What surprises me more is that so many people couldn't figure out "fetal spooning" at first. One of the few things in the early parts of the song that I heard clear as day on my first listen. That and "Holy fucking shit!" but mainly because I'm such a huge mark for vulgarity.