How do you know you took/ingested ENOUGH? I've averaged more than 50 grams per day over the past nineteen years, and that has been in health, not sickness. As the article by Dr. Cathcart pointed out, some maladies [at least initially] typically "produce" Bowel Tolerances of OVER 200 grams per day. If you did not reach Bowel Tolerance REGULARLY, then your body "wanted" more!
As an aside, WHERE did you get the idea that parasites "thrive" on ascorbic acid? Both logic and my reading on the subject leads me to believe just the opposite. If you have an infection(s), Pocket, you need all the ascorbic acid that you can get to deal with it [unless you prefer Antibiotics ]!