Hi Eirene-
You can get a lot of info regarding the effects of different foods on gas and bloating by reading the following:
"Gutbliss" by Robynne Chutkan
I got a copy from the library and think it's a good reference.
The major culprits are lactose, gluten and sugar...especially artificial sweeteners (so stay away from diet soda).
If you search on the title under "Join HealingWell", you'll see my post and others' comments.
My UC symptoms are under control but I still have major gas and bloating when I eat certain foods like broccoli so diet is key.
To ease the burning and itching, you can use vaseline or a water-based lubricant to coat the
opening and soothe the irritation.
Happy Christmas!
IAS