I really don't think digestive issues cause the intolerance of vitamin c. Poor digestion is one of the main problems with AF because fluctuating cortisol causes this. I think depending on what stage a person is has alot to do with their tolerance. Ascorbic acid is just plain horrible for the body. There is so much research to back this up. It just is not something our bodies can use. Treating our adrenals with natural occurring substances is so much easier on our bodies. When I started taking Rose Hips for my vc and bee pollen for the B5, my body was grateful.
I have used digestive enzymes some but it isn't recomended to use alot. I have been taking bitters to assist my liver in cleansing and producing more bile to digest. Taking so many unnatural substances is the same as taking drugs. They are meant for our bodies and don't promote healing.
I do think Dr. Lam knows alot about Af but their use of synthetic crap just isn't working for the majority. At first I started doing really well with his protocol but all of a sudden I spiraled down. It was a direct link to the ascorbic acid. Again, it is unnatural for our bodies. Rose Hips are good and even better is Amla. I eat Kiwi's too because they have more vc than oranges. Just my 2 cents anyway.