I've read that it's the casein protein in milk that may be the problem. If so, then whey products may be okay or non-cow milks that have different casein protein. There is still debate over whether it's the casein or the lactose.

There are non-dairy milks like rice, oat, soya, almond. I personally have rice milk, but there is hardly no protein in it. All rice milks, I think, have oil in them, so I make sure that there is no rapeseed oil. I don't know if rice-milk is good or bad, but I don't think anyone else does either, lol. There is debate over soya because of the toxins and aluminium in it.

I hope this helps a little.