I'm autistic and have digestive issues that go along with that anyway.
When I was in my teens and early 20s about 10 years ago, I drank lethal amounts of alcohol for 7 years and worked in retail (the worst profession for an autistic person because of the stress of social situations). This is when I began having severe hypoglycemia between meals and things just went south from there. I believe the alcohol severely damaged my pancreas and liver. I used to get severe pain right over the liver during those days.
I had to switch to a zero carb, high fat diet to alleviate the blood Sugar problems.
When I ate carbohydrates, I could tolerate over 30 grams of vitamin C just fine. On a zero carb diet, it is different because Vitamin C requires insulin to get into cells just like glucose does. I believe the vitamin C is raising my insulin like carbohydrates used to.