1 Lambert: I’ll cook a brace of coneys for our breakfast. What we really need is a few good taters.
2 Mordekai: What’s taters?
2 Lambert: Potatoes. You know.
3 Mordekai: This is a pseudo-medieval fantasy world based on Eurasian cultures. Potatoes won’t be introduced for several hundred years.
4 Lambert: Turnips then?
4 Mordekai: Bleah! I’ll wait for the taters.

I shared this comic with my friends and commented that I wasn't even sure if I'd ever eaten a turnip in my life.

One guy said that ohhhh, if I had eaten one, I'd have remembered it, because they're so awful.

Another guy said he grows turnips in his home vegetable garden, and although they are somewhat limited in use, he doesn't mind them at all.

Then the first guy said that he'd Googled and discovered that he wasn't thinking of turnips after all, he was thinking of parsnips, saying they're horrible white faux-carrot things that taste awful, and that now that he'd discovered what a turnip really is, he didn't think he'd ever tried them either.

And then the second guy said that he'd been reminded by his wife that what they were growing that he thought were turnips were actually radishes, and that now that he'd discovered what a turnip really is, he didn't think he'd ever tried them either.

So... from this sample, I can pretty much conclude that nobody has ever eaten a turnip, even people who think they have.