A 'good source of folic acid' apparently - at least according to a recipe using beetroot in this month's Good Food magazine that I happened to see earlier.
I always grow my own beetroot and then bottle it.I suppose the bought stuff is ok but like everything else goodness knows what stuff they put in it.I prefer to know what I am eating. You could buy fresh beetroot if you can't grow it and buy the pickling vinegar to do it yourself. Taste is much better too. Same goes for pickled onions. I hate the bought ones,they are so often soft and I like my onions crunchy!
raw beetroot does contain a lot of folic acid but once pickled and drained it only has 2micrograms of folic acid per 100g of beetroot. however, raw beetroot contains almost as much potassium as bananas, although the potassium content is approximately halved once pickled and drained.
oh and someone told me today that it might have something to do with the pigments in the beetroot, its probably something that was found a while ago but the media have only just caught on to the idea. i'd say it's good for you in the same way any other fruit or vegetable is good for you.