Bred in late 19th-century America, this pale and crispy salad vegetable brings fabulous texture to dishes, but it lacks the essential nutrients packed into greener leaves. "Iceberg lettuce provides a nice crunch but is low in nutrients, mostly consisting of water with a bit of fibre," says Jordan. "It's good for adding texture to salads, but it's not a nutritional star." Upgrade to a darker romaine or cos lettuce to get a little more nutritional value.

Now discover 34 so-called food 'facts' that simply aren't true

Last updated by Laura Ellis.

Ranked: the best and worst vegetables according to nutritionists