As I understand it, vitamins A, C, and E are all problematic, as is magnesium, if you are D type. If you are C type you will probably find calcium a problem. I have found supplementation particularly beneficial in my case; however, I do use a brand with particularly highly absorbent minerals (96% absorption) which means that virtually nothing gets to the colon. (I stopped nodding off behind the wheel in about 10 days. This, after a couple of years of fighting this off every afternoon.