DISCLAIMER: i'm not an expert, and i do not intend to act as one. someone with far more knowledge than myself please confirm what i'm about to say:
i've heard that when you boil veggies, (specially broccoli) they lose their nutrients in the boiled water and it is far better to grill or steam them to preserve their vitamins
my mother has always taught me this, and according to Dr. Google, it says some vegs may lose up to 50% of their vitamin C!
which is very worrying taking into consideration that holly boils all her vegs!