Examples of root vegetables commonly consumed by humans include carrots, parsnips, radishes and turnips. A root vegetable is defined as a vegetable that grows underground and is capable of absorbing water and nutrients from the ground for use by the plant. Many other foods that grow underground, such as potatoes and yams, are commonly called root vegetables, but are technically tubers because they don't absorb water and nutrients.
Bulb vegetables are also commonly referred to as root vegetables. This category includes many different varieties of onions and garlic. Corms, which are underground stems that grow vertically, are also considered root vegetables in some circles, according to Cooksinfo.com. Water chestnuts, taro and eddo are well-known corms. Rhizomes such as ginger and turmeric are also sometimes categorized as root vegetables.
Many root vegetables are noted for their high nutrient content. Carrots, for example, are known for being very high in vitamin A, a nutrient that's important for proper vision and tooth development. Beets contain high levels of folic acid, a nutrient that's essential for healthy pregnancy, and parsnips are a noted source of vitamin C, fiber and folate. Onions and garlic, although not true root vegetables, are thought by some to reduce cholesterol levels and protect against cancer thanks to their high antioxidant contents, according to Good Housekeeping magazine.