Cold cure?

I chopped up my last home-grown red cabbage for pickling this week. Cabbage layered with onions, a sprinkling of demerara sugar and covered with spiced vinegar.
It's a bit of a shame to hide the cabbage as I love the fractal-like patterns inside - ok, the same patterns are presumably there in green cabbage but not so visible.
I also love pickled cabbage on winter salads else I wouldn't be making it but while away at University my daughter and friends decided the vinegar from it made an excellent cold cure. Why it should, I have no idea - particularly as the same vinegar goes onto pickled onions and that apparently didn't have the same beneficial effects. Can cabbage really be that good for you?