We have a 9-month-old who has been sensitive to cow's milk in mom's diet for much of her life. Mom stopped consuming dairy around 2 months, and we've tried reintroducing it a couple times with poor results (say, 1 biscuit with maybe 1 tsp of milk caused problems).
We're now about 3 weeks into another reintroduction, which is going much better (YAY!). Mom's had primarily baked goods and cheese (not much, a slice or two on a sandwich every couple days). So it's obviously not causing issues like before.
I'm of the opinion that it's a fairly binary problem - either the milk proteins cause problems or they don't. Mom thinks it's more quantity-related, like mild lactose intolerance, where if our daughter gets too many milk proteins it will bother her.
Is there any research to back either one of us up?