I listened the the candida diet people for nearly 2 years about coffee being a bad thing. Previously, I wouldn't touch it with a 10 ft. pole.
I have determined that it causes me no upset whatsoever, and I am very, very sensitive to eating the wrong things such as too much sugar, grain, starch. I now enjoy a cup of coffee nearly every morning, I just make sure to buy low acid or acid reduced coffee. I don't sense that the coffee causes me any flare-up at all.
Trader Joes has a low-acid (steam processed) dark roast. There are a couple of others such as Hevla or Ecuatorial Coffee who make this specially processed coffee where they steam off the contaminents from the outer shell of the bean which is where they say the gastro-irritating properties lie.