On an ounce-for-ounce basis, turnip greens contain about 4 times more calcium than a much less bitter-tasting cruciferous vegetable. The glucosinolates in turnip greens are phytonutrients that can be converted into isothiocyanates (ITC's) with cancer-preventing properties. All cruciferous vegetables have long been known to contain glucosinolates, which shows us exactly how valuable turnip greens are in this regard.