Broccoli: healthy for humans and animals
And that's true: Dogs also need nutrients from fruit and vegetables, which they get in the wild from roots, grass or the stomach contents of their prey.
Some sources advise against feeding dogs broccoli, which can cause gas. Since it is one of the cabbage vegetables, that's also true. However, it only has this unpleasant effect in its raw state. If the broccoli is cooked, it is easily digestible and even healthy for the dog!
Broccoli contains calcium, vitamins C and B, potassium, sodium, iron, flavones and sulforaphane as well as selenium - all nutrients that not only humans but also their dogs need for a balanced diet.
So you are doing your dog good by giving him a serving of broccoli every now and then.
Like humans, dogs also have different tastes. If your dog doesn't like broccoli, try carrots or potatoes (caution: only cooked!).