Longlife Soy milk
Our son happily drinks So Good Regular Soy milk fresh from the refrigerated section- apparently this is the most fatty of soy milks. However, when I tried him on Longlife Soy milk, by the same brand, he ended up with diarrhea for 3 days! I had checked the ingredients list as well as the nutritional panel on both products. They were exactly the same. However, after a little internet research, I found a reference to the UHT process making the milk harder to digest. This is the only answer I can figure out. But no more long life milk for us. Oh, here's a tip... we couldn't get our son to drink soy milk initially but once we warmed it up slightly he loved it. Makes perfect sense when you compare it to breastmilk, but hindsight is always your friend ;-)
Our son loved the taste of Vegemite, but it gave him diarrhea for a week. For some reason, when you tell people this, they all let out a sigh and say yes, it's probably the yeast... but nobody every says anything about any problems when you tell them you're thinking about giving it to your child! Oh well, we'll give this another go in about a year when hopefully his digestive system improves.