It’s the electrolytes I believe. I had a Lucozade sport the other day (which have electrolytes) and that night when I collected colostrum, I collected double what I was usually getting. After looking into body armour and lucozade sport it seems it’s electrolytes!
I’m pretty sure it’s a US thing but I’ve been drinking the Asda own isotonic sports drinks, your looking for anything that aids hydration which most things do, even prime!x