"As grist for your [health] mill:" This MYTH [of ascorbic acid causing kidney stones] has been DEBUNKED many times over the years. If you take a look at the article you posted, you will see words like, "suggests," "may be," "suspected," "may," etc. A careful read should convince anyone that this article PROVES nothing and is really just fear-mongering.
And why would someone(s) want to spread this fear? As Schopenhauer wrote, "Really significant steps forward for mankind go through three stages. First, they are ridiculed. Second, they are heavily fought by those who have economic interests in the status quo. And finally, when the dam is breaking, everyone says: Well we knew it all along." Just the moneyed-interests in this world trying to "protect their turf!"
Dr. Cathcart personally dosed over 25,000 patients, over a thirty-five year career, and never once found any of his patients devolping kidney stones. In fact, he stated, if anything, it cured them of the problem [primarily because of the increased acidity in their urine].
I should add that I have averaged over fifty grams of ascorbic acid per day over the past nineteen years, and currently often ingest one-hundred grams per day, with nothing but the best of health to show for it, e.g. I take no drugs whatsoever, do not see doctors at all, never feel ill, and am simply never sick. Kidney stones?