Food/drinking and breastfeeding

Hi!Im a father of two beautiful kids, one being 2,5yo and our 2nd kid is soon 3months.My SO has always heard from her mother that some foods/drinks will make it so our child gets a stomach ache through the milk when breastfeeding him, and our daughter when she was a few months.Now im curious if other mothers out there has heard the same and/or read anything about it, because all i can seem to find is that chocolate can make their skin a bit red but has nothing to do with stomach ache.My MIL has said that these things, even in extremely small doses basically will give the baby a stomach ache when breastfeeding. These things are; Any onions, strawberrys, cabbage, drinking sodas etc, and more that i cant remember atm.Now I dont want to prove my SO wrong, however im curious because i cant seem to find a single article about it except a few that only says you shouldnt be drinking too much wine, but that you still could take a glas or two once in a while. But this still doesnt have anything to do with the child getting a stomache ache.Anyone out there that got good information about this topic? via /r/Parenting https://ift.tt/3kwETGp