Earlier quoted context omitted.
Oh yes. After Linus Pauling advocated high vitamin C doses, lots of people started taking synthetic vitamin C, which turns out to be carcinogenic. A product called Geritol was marketed to the elderly for many years on the premise that they were iron deficient. Geritol was behind lots of cases of iron poisoning. We laugh at the quaintness of the snake oil salesman or yore -- but he never left, not really. ==== Edit ==…
Synthetic vitamin C is exactly the same as real vitamin C. [1] When I Googled "synthetic vitamin C carcinogenic" I found a bunch of quackery and the Scientific American article. Mostly the sites were screaming "IT'S A CHEMICAL!! CHEMICALS ARE BAD!!!!" as if water and foods aren't also made up of chemicals... :| [1] http://blogs.scientificamerican.com/guest-blog/natural-vs-sy...
Not to do with synthetic vitamins, of course, but certainly to do with the selling of vitamins as something you need to supplement.