Question: What do you mean by "high doses of C (ascorbic acid)," i.e. how much is "high?" Some people consider a gram or two a day "high."
Did you take a look at Dr. Cathcart's article? If so, you note that to ameliorate the symptoms of some health maladies, i.e. reach their Bowel Tolerance dose of ascorbic acid, some people needed in excess of 200 grams daily. So my question for you, IO, is were you reaching your Bowel Tolerance [daily] with ascorbic acid over those "years?"
I am just asking as an assitance to you in your search for a solution to your health situation.