Dairy is just one of the most common foods that upsets people's digestion. So many people have trouble digesting it that it is always the first thing doctors tell you to avoid. I think besides the proteins and lactose that the mucus causing properties add to its irritation to the digestive tract.
-------------------- IBS-A for 20 years with terrible bloating and gas. On the diet since April 2004. Remember this from Heather's information pages:
"You absolutely must eat insoluble fiber foods, and as much as safely possible, but within the IBS dietary guidelines. Treat insoluble fiber foods with suitable caution, and you'll be able to enjoy a wide variety of them, in very healthy quantities, without problem." Please eat IF foods!