The great soy

While at my chiropractor I was warned about the excessive estrogen in soy based formula. I was told that the typical daily amount of formula a baby receives has the estrogen equivalent of 6 birth control pills. My lo is spitting up really bad. I've tried the similac sensitive and the one for spit up and the enfimil AR. I've added rice cereal to her bottle. Nothing has helped. She's gaining weight and at 4 months she is now in the 35th percentile (up from 15th percentile at 2 months). The only thing that she keeps down is soy.  The chiropractor said that he has treated babies for reflux, but I'm leery about that too. Her pediatrician said I shouldn't be concerned since it doesn't seem to bother her and she's gaining weight (laundry problem vs baby problem). She gives good burps with the soy and it all stays down. I'm not sure what to do at this point.