Yes, it is safe to eat cruciferous vegetables every day. This includes broccoli, cauliflower, cabbage, kale, brussel sprouts, and bok choy. You should continue eating these foods even if you are taking supplements or herbal remedies.
There are two types of cruciferous vegetables: Brassicas (cabbages, broccoli, kale, cauliflower) and Cruciferae (mustard greens, arugula, chives, radishes).
You can also find them at the store as part of a salad mix or in a Chinese stir fry. They are also very common in cooking, especially in Asian dishes. The major phytonutrients in cruciferous vegetables are glucosinolates and indole-3-carbinol (I3C). The main glucosinolate found in broccoli is sulforaphane. Sulforaphane is an antioxidant that protects cells from damage caused by free radicals. It also has anticancer properties. Sulforaphane is converted into I3C by the enzyme myrosinase which is present in both the Brassicas and Cruciferae vegetables.