PACKED WITH ANTIOXIDANTS
Preserve memory
Control diabetes
Reduce the risk of heart disease and cancer
Have you ever wondered how Scarlett O’Hara maintained her 19-inch waist? One secret may have been sweet potatoes. Before Scarlett went to a barbecue, her nanny dished up sweet potatoes to keep her from filling up on fattening party fare. We can almost hear Scarlett’s gentle protest—“Why, I can’t eat a thing!”—as she pushed away temptation, filled up as she was by those sweetly nutritious, oddly shaped little tubers.
Sweet potatoes are more than just a filling food, of course. A member of the morning glory family (except in name, they’re not related to white potatoes), they contain a trio of powerful antioxidants: beta-carotene and vitamins C and E. This means that they can play a role in preventing cancer and heart disease. And because sweet potatoes are rich in complex carbohydrates and low in calories— there are 117 calories in a 4-ounce serving—experts recommend them for controlling weight and weight-related conditions like diabetes.
Experts often recommend sweet potatoes for their high amounts of beta-carotene. A 4-ounce serving will provide more than 14 milligrams of beta-carotene. They are an easy way to get the heart-health and cancer-fighting benefits into your diet, says Pamela Savage-Marr, RD, a health education specialist at Oakwood Health Care System in Dearborn, Michigan.
As do vitamins C and E and other antioxidants, beta-carotene helps protect the body from harmful oxygen molecules known as free radicals, says Dexter L. Morris, MD, PhD, associate professor in the department of emergency medicine at the University of North Carolina School of Medicine at Chapel Hill. Eating sweet potatoes and other foods that are rich in beta-carotene helps neutralize these molecules before they damage various parts of the body, such as the blood vessels or certain parts of the eye.
In a study of almost 1,900 men, Dr. Morris and his colleagues found that men who had the most carotenoids in their blood—not just beta-carotene but also such phytonutrients as lutein and zeaxanthin—had 72 percent fewer heart attacks than those with the lowest levels. Even smokers, who need all the protection they can get, showed the benefits: Those who got the most of these protective compounds had 25 percent fewer heart attacks than those who got the least.
Is that thing really a sweet potato? Sweet potatoes come in all shapes and sizes, so don’t be surprised if the veggie touted by that name at your supermarket looks a little different from month to month. Sweet potatoes can have skin that’s white, yellow, orange, red, or even purple. Inside, the flesh may be yellow or deep orange. But don’t call it a yam—true yams are grown in South America, the Caribbean, and Africa. They have brown or black outer skin and flesh that’s off-white, purple, or red and tastes sweeter than that of a sweet potato. Most “yams” sold in US supermarkets are really sweet potatoes.
Because they are cured (meaning that they are kept in high humidity and temperatures for about a week and a half ) by growers before they are shipped to market, sweet potatoes are excellent keepers and will stay fresh for about a month after you bring them home from the store. It’s important, however, to store them carefully to prevent them from going bad.
Keep them cool. Sweet potatoes should be stored in cellars, pantries, or basements, where temperatures stay around 45° to 55°F. (Don’t put them in the refrigerator, since this shortens their shelf life.) When sweet potatoes are stored at room temperature, they’ll keep for about a week.
Store them dry. Sweet potatoes will spoil once they get wet. That’s why it’s best to store them dry, then wash them only when you’re ready to start cooking.
Treat them gently. Sweet potatoes spoil quickly when they get cut or bruised, so don’t buy them if they look damaged. At home, treating them gently will help ensure their longevity.
Bake a big batch. Baked sweet potatoes will keep in the refrigerator for 7 to 10 days. To bake, scrub the potatoes, dry them, and pierce the skins in several places. Place them on a baking sheet covered with aluminum foil (to catch dripping juices) and bake at 350°F for about 1 hour. Any leftovers can be reheated in a microwave oven or mashed with trans-fat-free margarine (buy a brand that’s low in saturated fat, too) and a dab of brown sugar for a quick side dish later in the week.
Sweet potatoes are also a rich source of vitamin C, with a 4-ounce serving providing 28 milligrams, or nearly half the Daily Value (DV). In addition, the same-size serving provides 6 IU of vitamin E, or 20 percent of the DV. “That’s a very difficult nutrient to get from natural sources,” says Paul Lachance, PhD, executive director of the Nutraceuticals Institute at Rutgers University in New Brunswick, New Jersey.
Since sweet potatoes are a good source of fiber, they’re a very healthful food for people with diabetes. The fiber indirectly helps lower blood sugar levels by slowing the rate at which food is converted into glucose and absorbed into the bloodstream. And because sweet potatoes are high in complex carbohydrates, they can help people control their weight, which also helps keep diabetes under control.
Choose sweet potatoes over white potatoes. Harvard School of Public Health nutritionists say it’s always smart to choose a more colorful vegetable over a less colorful one. That alone would make sweet a better choice than white when it comes to potatoes. The sweet potato’s orange flesh is a richer source of beta-carotene and vitamins. But there’s a new reason: Sweet potatoes are better for your blood sugar. Despite their name, and a flavor so divine it makes a good dessert, sweet potatoes don’t raise your blood sugar as high, or as fast, as white potatoes do.
The connection between weight and blood sugar levels is not a casual one. About 85 percent of people with type 2 (non-insulin-dependent) diabetes are overweight. Since sweet potatoes are so satisfying, you’re less likely to reach for other, fattier foods.
The resulting weight loss can cause a dramatic improvement. In fact, losing even 5 to 10 pounds will help some people maintain normal blood sugar levels, says internist Stanley Mirsky, MD, associate clinical professor of metabolic diseases at Mount Sinai School of Medicine in New York City and author of Controlling Diabetes the Easy Way.
In addition to fiber and antioxidant vitamins, sweet potatoes also contain the B vitamins folate and B6. These are the vitamins that may give the brain a boost in performing some of its functions, which can diminish as we age.
In a study at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, researchers looked at the levels of folate and vitamins B6 and B12 in the blood of 70 men ages 54 to 81. Men with low levels of folate and B12 had higher levels of an amino acid called homocysteine. High levels of homocysteine were linked to poorer performances on spatial tests such as copying a cube or a circle or identifying patterns.
Shop for color. When buying sweet potatoes, always choose those with the most intense, lush orange color. The richer the color, the greater the jolt of beta-carotene, says Mark Kestin, PhD, professor of nutrition at Bastyr University and affiliate assistant professor of epidemiology at the University of Washington, both in Seattle.
Have a little fat. While some vitamins dissolve in water, beta-carotene requires the presence of fat to get through the intestinal wall, says John Erdman, PhD, a beta-carotene expert and professor of food science and human nutrition at the University of Illinois in Urbana-Champaign. In most cases, you’ll get the necessary amount of fat, usually 5 to 7 grams, in other foods you’ll be having with your meal, he explains.
Scrub the sweet potatoes and pat dry with paper towels. With a fork, pierce each potato in 3 or 4 places. Place the potatoes, in spoke fashion and with the thinner ends pointing toward the center, on a paper towel in a microwave oven. Microwave on high power for 5 minutes. Turn the potatoes.
Microwave for 5 to 8 minutes more, or until the potatoes can easily be pierced with the tip of a sharp knife but are still firm. Set aside until cool enough to handle. Peel, then cut into thick slices.
Place the sesame seeds in a large nonstick skillet. Stir over medium heat for 30 seconds, or until golden. Stir in the scallions, olive oil, and garlic. Cook for 30 seconds longer, or until fragrant. Add the soy sauce, brown sugar, and sesame oil. Cook until the sugar melts, about 10 seconds. Add the sweet potatoes to the pan, and toss to coat. Cook for 1 minute to heat through.
Makes 6 servings
Calories: 208
Total fat: 5.6 g
Saturated fat: 0.8 g
Cholesterol: 0 mg
Sodium: 275 mg
Dietary fiber: 4.7 g