G.E.R.D. and cereals?

My 7 and a half week old son has been on single grain rice cereal since he was 2 weeks old because he has GERD and can't keep anything down unless it has significant weight to it. He did really well when we first put him on it but has had colic ever since. Today I was told that not only can the rice cereal cause that but it's a lot less healthier than oatmeal cereal. Does anyone know this to be true? He is out of rice cereal so tonight when I go to pick up more, should I get the oatmeal?? Have you tried both and if so, which do you prefer? Does oatmeal stink less?? Thanks!