I got into an argument with some likely-malnourished guy today about how vitamin supplements are borderline-necessary to keep yourself healthy these days. He told me the title quote.
He then sent me this study--don't worry, it's archived--and I naturally started looking for who FUNDED the study.
Well, blow me down, it was the Canadian government. Nope, can't say anything that endangers the gravy train of government grants, no sir!
Obviously, that was all I needed to dismiss it. Truck Fudeau. He took that as surrender. Truck him too.
But whatever, I thought I'd vent some steam a little, because remember: 97% of all scientists agree with who writes the checks.
There's an OCEAN of scientific and other data on the benefits of over-the-counter supplements, and there HAS BEEN for many decades. I just pulled my copy of Life Extension: A Practical Scientific Approach Adding Years to Your Life and Life to Your Years (original Warner printing 1983, copyright dates 1982 and portions earlier), by research scientists Durk Pearson and Sandy Shaw off the shelf; it runs 858 pages.
Almost twenty years before that was published, my grandmother told me that one glass of orange juice (which has at most perhaps 100mg of C and perhaps less than 35mg) has "all the vitamin C you can use in a day" for the same reason your friend used -- you'll just piss it out.
It's odd that no-one says that about water -- why drink a second glass today, you'll just piss it out? -- but propaganda takes hold and supporting reasons get created and the propaganda gets embedded even more tightly.
We DO piss out the C we take in, and THAT'S WHY WE NEED TO TAKE IT MORE OFTEN. Most mammals make vitamin C constantly and they make a LOT of it; humans have a defective gene for C manufacture and that's why dogs never get scurvy but we DO. The RDA for C is 75mg for adult females and 90mg for adult males, which is probably, yes, enough to keep you from dying from scurvy but nowhere near enough for optimal health.