Growing up, when my mom made any kind of vegetable, she always saved the cooking water, and used it later as an addition to soups or other dishes. The reason for this is that as vegetables cook, some of their nutrients leach out into the cooking water, which means if you toss the cooking water, you are tossing valuable nutrients down the drain.
I now use this trick not only for myself, but for recipes I make for my dog. Some of my recipes have the vegetable cooking water embedded in them — like when I make a big batch of stew, soup or other dishes where the liquid remains in the pot. Other times, when I steam vegetables by themselves, I am left with valuable cooking water which I save. Sometimes I will use it, and other times I add it to my dog’s recipes.
Do this favor for yourself and your dog, and you will be helping to maximize your nutrient intake.