They're packed with nutrients but high in starchy carbohydrates.
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Root vegetables — like turnips, rutabagas, and parsnips — may not be the sexiest foods on the table. But they're big celebrities in a number of cuisine trends like the "vegetable forward" movement (which elevates vegetables into creative entrees and side dishes) and root-to-stem cooking (which uses every part of a vegetable, including the tops, stems, and skins).
While it's fun to use old standbys in more interesting ways (like roasted parsnips with pistachio and lemon), it's important to eat root vegetables judiciously. "They are so high in carbohydrates that they are more like grains than greens. It makes more sense to put them in the same category as breads, rice, or pasta," says dietitian Teresa Fung, adjunct professor in the nutrition department at the Harvard T.H. Chan School of Public Health.
What are root vegetables?
Root vegetables grow underground at the base of a plant. Technically they're not all roots; some are bulbous growths that store nutrients to feed the plant in colder months.
Examples include bulbs (fennel, onions), corms (celery root, water chestnut), rhizomes (ginger, turmeric), tap roots (beets, carrots, parsnips), tuberous roots (sweet potatoes, yucca), and tubers (potatoes, yams).
The bulbs, roots, and tubers absorb water and nutrients to feed the rest of the plant. Those nutrients make them dietary powerhouses for us.
The pros of root vegetables
Root vegetables are low in calories and high in antioxidants. Each one contains a wide variety of vitamins and minerals. Some have nutrients in surprisingly high amounts. For example:
The flesh of a medium baked sweet potato has only 103 calories and enough vitamin A — 1,096 micrograms (mcg) — to meet your entire Recommended Dietary Allowance for the day (for adults 51 or older, that's 700 mcg for women, 900 mcg for men). Carrots are also a good source of vitamin A, with 1,069 mcg in a cup of chopped raw carrots.
A cup of mashed turnips has 51 calories and 76 milligrams (mg) of calcium — as much calcium as half of a slice of cheddar cheese.
A medium baked russet potato (including its skin) has 164 calories and 935 mg of potassium (more than twice the potassium of a medium-sized banana).
The cons of root vegetables
Most root vegetables are also starches — a kind of carbohydrate that the body breaks down into glucose for energy. For example, there are 37 grams of carbs in a baked russet potato, and 24 grams in a medium baked sweet potato.
Fung warns that if you eat more carbs than your body needs, it will store them as fat, leading to weight gain. Eating too many carbs in one sitting can spike your blood sugar. Frequent spikes of blood sugar can increase the chance of developing diabetes and make it more difficult to manage diabetes if you already have it.
Still, some root vegetables have fewer carbs than others. For example, a cup of chopped raw carrots has only 12 grams of carbs; a large cooked onion has 13 grams of carbs.
Another potential problem: how you prepare root vegetables. "When you eat mashed potatoes you're probably adding butter and other unhealthy ingredients. Or maybe you top a baked potato with sour cream and bacon bits. And it's quite easy to overeat, and you end up eating a lot of calories that aren't so satiating," Fung says.
What you should do
Root vegetables are still fresh whole foods that contain many vitamins and minerals. Eating a variety of them is good for your health.
Fung says that, if you're healthy, you can probably eat one serving of root vegetables every day. "Just make sure it's a side dish or part of another dish, and that it's the only starch on your plate," she advises. In other words, don't have a serving of rice and a serving of sweet potatoes.
And don't eat the same root vegetables all the time; eat a variety of them to get a wider selection of nutrients. Try turnips, yucca (cassava), Jerusalem artichoke, yams, beets, or radishes.
If you're looking for easy ways to eat root vegetables, try them boiled, mashed, baked, roasted with a little olive oil, or tossed into soups and casseroles. Alternatively, you can follow a food trend and get creative with root vegetables. The secret is using atypical cooking methods (such as braising, barbecuing, or searing) and then pairing the vegetables with interesting flavors. Consider barbecued carrots with yogurt and pecans, miso-glazed turnips, or Jerusalem artichoke with shallots and toasted hazelnuts.
With a little imagination, you may soon find root vegetables a lot more interesting.