They might not do well with a digestive track problem. Cabbage is also known to cause gas.
I like cabbage. I do not like turnip (nor parsnips). I've tried. I've tried about every turnip variation you can think because almost every time I mention that I don't like turnip they try to feed it to me in a way that they're sure I'll like it.
No... No, that [beep.wav] is disgusting. They can take their turnip and [beep.wav] right off with the [beeeeeeep.wav]. I do not like turnip. My mother liked the stuff and used to sneak it into all sorts of stuff, like beef stew. Horrible, horrible stuff. It's food unfit for human consumption, as far as I'm concerned.
I've eaten a goat's eye, sheep brains, and hot dogs made from cow tongue (and so much more), but turnip is right out of the question.