As far as I know, there are some enzymes, synthesis of which could be triggered by presence of lactic sugars, so a cell could convert them into ATPs, and those

As far as I know, there are some enzymes, synthesis of which could be triggered by presence of lactic sugars, so a cell could convert them into ATPs, and those enzymes are encoded in the DNA. My bet is that they are "switched off" after the period of breastfeeding is passed, but could be "re-activated", and this ability to reactivate them is the survival factor.