Fermented sauerkraut is made from Brassica plants containing defense chemicals that are only partially degraded by fermentation.

“what about fermented sauerkraut okay it's probably better than nothing but remember that you are fermenting a cabbage which is a Brassica type of plant which has defense chemicals I thought isothiocyanate those are mostly degraded when you ferment it but you are taking a plant that is I believe toxic to humans has plant defense chemicals they are degraded somewhat by the hermination process but I still don't think it's the best use of that plant or the best source of fermented foods”