Gassiness in baby related to moms diet?
It could be. Now, don't think things like beans when you think of what could be causing it. Think about things they may be sensitive to without you even realizing it. I had one baby who was sensitive to strawberries, she wont even eat them to this day. My youngest was milk intolerant and would react to tomatoes too. Not sure why, but those were is triggers.
You can start by eliminating food groups while you nurse. A big offender seems to be dairy so I would start with that.