Manganese is a magical element too. I've been supplementing with it as a powerful antioxidant. Beets do have a lot of manganese. The problem with beets, for me, is that they have a LOT of iron. Iron constipates me; as it does most men.
BTW: baked beets are wonderful. Just bake them as you would a potato. Cut them in half, put a little butter in between the halves, wrap in foil and bake.