How nutritious are sweet potatoes?

The Nutrition Action Health Letter rated 58 vegetables by adding up the percentages of United States Recommended Daily Allowances for six nutrients (vitamins A and C, folate, iron, copper and calcium) and fiber. Sweet potatoes topped the list with 582 points. A raw carrot was second at 434.

The Center for Science in the Public Interest rated the relative nutritional value of common vegetables. The sweet potato placed first with 184, compared with a similarly prepared white potato which scored only 83 points. One cup of cooked sweet potatoes provides 30 milligrams of beta carotene (vitamin A).

Sweet potatoes have four times the recommended daily allowance for beta-carotene when eaten with the skin on.

Sweet potatoes are a great source of vitamin E, and they are virtually fat-free. Most vitamin E-rich foods, such as vegetable oils, nuts and avocados, contain a hefty dose of fat. Just two-thirds of a cup of sweet potatoes provides 100 percent of the recommended daily allowance for vitamin E without the unwanted fat.

Sweet potatoes provide many other essential nutrients including vitamin B6, potassium and iron. Sweet potatoes are virtually fat-free, cholesterol-free and very low in sodium. A medium sweet potato has 118 calories.

Q: What’s the best way to prepare sweet potatoes?

A: Enjoy the flavor of sweet potatoes without drowning them with marshmallows, brown sugar and butter. Sweet potatoes also can be served raw to make a great snack for dipping. Here are directions on how to simply prepare them:

Fresh: Wash and peel sweet potatoes. Cut into sticks or rounds. Place cut potatoes in ice water or in a plastic bag with several ice cubes for 10 minutes. Drain and serve or store in plastic bags in the refrigerator for up to four days. When prepared this way, sweet potatoes will not discolor. Raw sweet potatoes go with many different kinds of dip. Try applesauce, salsa or low-fat ranch.

Baked: Prick the skin and bake at 400 degrees for 40 to 50 minutes or until done.

Microwaved: For best results, choose sweet potatoes that do not vary much in width from center to ends. Pierce washed sweet potatoes. Cook on high, turning each potato halfway through cooking time. Remove from the oven and wrap in aluminum foil and allow to rest for at least 5 minutes. Cooking times: 1 medium, 3-4 minutes; 2 medium, 5-6 minutes; 3 medium, 7-8 minutes; and 4 medium, 8-9 minutes.

Steamed: Bring 1 1/2 inches of water to boil in a steamer. Place whole, unpeeled sweet potatoes in a steam basket; steam until tender. Allow 40 to 50 minutes for an 8-ounce sweet potato. When peeled and cut into one-inch cubes, sweet potatoes will cook in about 30 minutes.

Boiled: Place whole sweet potatoes in boiling water and cook 35 to 45 minutes, depending on their size.

Mashed: Place whole potato (unpeeled) in boiling water and cook 35-45 minutes, or until it gives easily when pricked with a fork. Drain immediately and peel. Mash with a potato masher, fork or electric mixer.

Grilled: Wrap medium-size sweet potatoes individually in heavy-duty aluminum foil. Place on the grill about 5 inches from coals. Cook for about 45 minutes or until tender. To hasten, boil 10 minutes before wrapping in foil, and bury in coals.

French fried: Boil sweet potatoes for about 10 minutes. Peel, if desired, and cut into strips. Heat oil to 365 degrees. Cook until golden. Drain, sprinkle with salt and/or ground nutmeg.

Toasted “chips”: Scrub the sweet potatoes. Cut into 1/4-inch thick slices. Brush each side lightly with olive oil. Season with salt and pepper if desired. Place the slices on a baking sheet and bake in a preheated 350-degree oven for 15 minutes. Turn the “chips” and bake another 15 minutes or until both sides are lightly toasted.

Sauteed: In a large deep skillet, heat 1 1/2-inch deep vegetable oil to 365 degrees. Add sweet potato strips to cover bottom of skillet. Saute 5 minutes or until brown and tender. Remove from hot oil and drain on paper towels. Sprinkle with salt.