Just don't overdo on the broccoli. It can cause problems if they eat too much.
http://www.vetinfo4dogs.com/dtoxin.h...oli%20toxicity
Broccoli toxicity
Q and nudge: Dear Mike, This is follow-up on yesterday's conversation just to remind you. If the stuff is a no-no for dogs as well as ex-Pres. Bush, maybe it's worth noting in your web site. Thanks, NvB
A: It is always good to remind me of things -- I had forgotten.
Broccoli toxicity has been noted in livestock. Apparently in California it is widely available at certain times and the dairy cattle there are fed broccoli due to this. If the percentage of broccoli in the diet exceeds 10% it can cause gastrointestinal upsets and if it exceeds 25% it is fatal.
I could not find any references to problems with broccoli in small animals, probably because no one feeds them more than 10% of their diet as broccoli or possibly because they don't have rumens and therefore don't digest the broccoli as thoroughly.
The toxic ingredient in broccoli is isothiocyanate and it is reported to be a pretty potent gastrointestinal irritant.
So G. might be right. But I did find several references suggesting that broccoli should be fed to pets because of the bioflavinoids in it and their cancer fighting capabilities. So he might be wrong.
Personally, I wouldn't worry about it unless you are planning on feeding a lot of broccoli at one time to Kate. But your daughter might want to follow her vet's advice or find out if there is more evidence of toxicity than I can find.
Mike Richards, DVM
Also for broccoli and potatos (and others) see this link
http://www.heathershomemadedogtreats.com/toxic.html