Many dinner tables sport sweet potatoes for the holidays here in the United States, but it is now well known that sweet potatoes or yams are eaten on six continents. The two root vegetables are actually very different plant foods with similar properties and nutritional composition.

"There is a great deal of confusion, because the names are interchanged," says Julie Paff, RD, LD, who teaches diet and diabetes self-management strategies to persons with diabetes and impaired glucose tolerance. She and other Seton Family of Hospitals health professionals host regularly scheduled seminars at multiple Seton facilities to help people learn more about pre-diabetes and diabetes in addition to teaching classes on diabetes nutrition, weight management and healthy eating. This story is in answer to a question posed to her at the last diabetes seminar.

"Both are served as starchy vegetables or in sweet desserts. Yams are rarely available in American supermarkets. Some of the name confusion likely resulted from African American slaves noting the resemblance of sweet potato to their native yam and using them in traditional recipes. The United States Department of Agriculture has tried to implement mandatory labeling to distinguish between yams and sweet potatoes, but in US markets it is still likely that a sweet potato is labeled as a yam," adds Julie.

Comparing Sweet Potatoes and Yams

However you slice them, these high-fiber starchy vegetables are recognized on tables around the world. While unrelated, a 1/2 cup portion of either vegetable is about one carb choice for persons with diabetes. The fiber content helps make both vegetables lower glycemic foods than Irish potatoes. Both are great sources of antioxidants and anti-inflammatory nutrients. Both vegetables are good sources of Vitamin B-6.

Below is a table to help you compare and contrast these staples in the world diet.

	Sweet Potato	Yam
Scientific classification: Both are vines but are unrelated biologically.	400 varieties. Order: Solanales Family: Convolvulaceae Genus: Ipomoea Related to morning glories and are dicotyledon (two embryonic seed leaves).	200 edible varieties. Order: Dioscoreales Family: Dioscororeaceae Genus: Dioscorea Related to lilies and grasses and are monocotyledon (one embryonic seed leaf)
Native to:	Central America, domesticated 5000 years ago. Peruvian cave relics suggest sweet potatoes eaten 10000 years ago.	First cultivated in Africa and eaten in Asia since 50,000 BC
Vegetable type:	Tuber, with following characteristics: 4-6 inches long Weighs up to 2 pounds Skins easy to peel Flesh is yellow to orange Safe to eat raw	Tuber, with following characteristics: Up to 8 feet long Weighs up to 150 pounds, but more typically 6-12 pounds. Skins difficult to peel Flesh white or yellow to purple or pink Some species must be cookednatural substances can cause illness if eaten raw and yam fluids can cause skin itching.
Other names:	Batata, papata, camote, kumar, kumara, uala, kaukau, murasake imo, satsumaimo, beni imo, yamaimo, hongshu, ganshu, ubi jalar, ratala, kanhamula, bathala, khoai lang, kamote, goguma, ngwaci and boniato.	Ube, nagaimo, yamaimo, olhuala, khoai m, ratalu, uhi, oca, taro, inhame, name, adamwanga and doya.
Nutritional Value:	Per 1 cup portion: 180 Calories 0 gm Fat 41 gm Carbohydrate 7 gm dietary fiber 26%DV 13 gm sugar 4 gm protein 38,433 IU Vitamin A 769%DV 39 mg Vitamin C 65% DV 950 mg potassium 27% DV 1.0 mg manganese 50% DV 0.26 mg copper 13% DV 0.3 Vitamin B-6 13% DV	Per 1 cup portion: 158 Calories 0 gm Fat 37 gm Carbohydrate 5 gm dietary fiber 21% DV 1 gm sugar 2 gm protein 16 mg Vitamin C 27% DV 911 mg Potassium 26% DV 0.5 mg manganese 25% DV 0.2 mg copper 10% DV 0.3 mg Vitamin B-6 16% DV Wild yam contains diosgenins, a steroidal saponin that is potentially beneficial in menopausal symptoms and osteoporosis; to date, the benefit is not conclusively proven by clinical research.
General information:	Sweet potatoes can be baked boiled or fried. Can be added to soups, casseroles, puddings, or substituted for white potatoes in most recipes. Best stored at 55 to 65 degrees Fahrenheit. Peak season in October is typically November to December. Americans consume almost 5 pounds of sweet potatoes per person per year.	Yams may be served fried, boiled, or pounded into fufu dough balls. Peak season is October through December. In the Philippines, purple yams are eaten as a sweetened dessert, halaya. In Vietnam, purple yams are used in a soup, canh khoai m In Japan, yam is eaten raw after soaking in vinegar to neutralize irritating oxalate crystals. In Africa, yam powder is used to thicken foods
Serving methods:	Puree cooked sweet potatoes with brown sugar, cinnamon and nutmeg. Pairs well with turkey or ham.	Puree cooked yams with a little milk, and season with tamari, coriander, cumin or cayenne. Pairs well with venison or duck. Steaming decreases phytic acid (which can block zinc and iron absorption)
Global awareness:	Native Americans were growing sweet potatoes when Columbus discovered America. It is unclear if sweet potatoes were brought to Polynesia from South America, for from South America to Polynesia.	The Portuguese and Spanish brought yams to Brazil and Guyana. From here, the yam was introduced to other parts of the Caribbean. African yams introduced to Europe in 16th century and later take to Americas by Portuguese and Spanish
Cultural significance:	George Washington grew sweet potatoes in Mount Vernon. George Washington Carver developed 118 different products from sweet potato, including sizing for cotton fabrics, mucilage for postal stamps, and an alternative to corn syrup. During World War I, powdered sweet potato was used to extend the rationed supplies of wheat flour.	In Tonga, the names of the month relate to the growth cycle of the yam. Yams are included in Nigerian in worship ceremonies. In Japan, yams are part of folk remedy for impotence
Top world producers:	China is the top world producer, but half the Chinese crop is used to feed livestock. Other top world producers: New Guinea, Solomon Islands, Burundi, Rwanda, Uganda, New Zealand. In the US, top states to produce sweet potatoes are North Carolina, California, Louisiana, and Mississippi.	Primary agricultural commodity for West Africa and New Guinea. Top world producers are Nigeria, Ghana, Cte dIvoire, Benin, Togo, Colombia.

Either One A Healthy Choice

"While the two vegetables are sometimes confused and interchanged in recipes, they are both healthy choices loaded with antioxidants, soluble fiber and minerals. These foods are a great addition to any diet, including the diet of persons with diabetes or pre-diabetes. The key consideration is the total carbohydrate contribution for the meal if a person with diabetes is seeking optimum blood sugar control," says Julie.

"Incorporating sweet potatoes or yams with other lower carb vegetables is a great way to decrease the total carb load. Sweet potatoes and yams pair well in mixed dishes with cauliflower, carrots, and parsnips. Always consider substituting sweet potatoes or yam in recipes calling for white potatoes if you need to increase your fiber intake. The health benefits of fiber include lowering cholesterol levels and improving blood sugar control. Try to get 25- 35 grams of fiber each day."

Sweet Potato Recipes

The following are several recipes to try this holiday season or any time of the year.

Sweet Potato and Pumpkin Puree

4 servings

Ingredients:

1 Tablespoon olive oil
1 medium yellow onion, chopped
2 celery ribs, chopped
2 medium sweet potatoes (1 pound total), peeled and chopped
1 15-ounce can pumpkin
1 1/2 cups fat-free reduced sodium chicken or vegetable broth, plus more to thin puree
1/8 teaspoon ground cinnamon
1/8 teaspoon curry powder
1/8 teaspoon ground white pepper
Salt to taste
3/4 cup low fat sour cream, divided
1/4 cup chopped fresh parsley

Directions:

• In a large saucepan, heat the olive oil over low heat. Add the onion and celery and saut for 5 minutes, until soft and translucent.
  
  
• Add the sweet potatoes, pumpkin, broth, cinnamon, curry powder, and pepper. Season to taste with salt.
  
  
• Bring to a boil, reduce heat to low and simmer, covered, until the sweet potatoes are very tender, about 15 minutes, Let cool slightly.
  
  
• In a blender or food processor, carefully puree the mixture in two batches (add more hot broth to thin the puree if needed) and return it to a saucepan. Heat through.
  
  
• Stir in 1/4 cup of the sour cream and adjust the seasonings. Serve hot, with a dollop of the remaining sour cream and a sprinkle of parsley on top of each serving.

Nutrition per serving: 224 Calories, 8 gm total fat (4 gm saturated fat), 33 gm carbohydrate (2 carb choices per serving), 7 gm protein, 6 gm dietary fiber, 234 mg sodium.

Sweet Potato Chili with Peanuts

10 servings

Ingredients:

2 Tablespoon canola oil
1 medium onion, chopped
2 medium carrots, peeled and thinly sliced
1 medium green pepper, seeded and chopped
1 medium red bell pepper, seeded and chopped
2 to 4 garlic cloves, minced to taste
1 1/2 to 2 pounds orange-fleshed sweet potatoes, peeled and cut into bite-sized chunks (about 4 cups)
1 1/2 cups unsalted roasted peanuts
1 28-ounce can crushed tomatoes in juice
2 4-ounce cans diced mild green chilies with liquid
4 to 6 Tablespoons chili powder, or to taste
1 Tablespoon ground cumin, or to taste
1 Tablespoon sugar
Salt and pepper to taste.

Directions:

• In a large heavy pot, heat the canola oil over medium heat. Add the onion, carrots, and bell peppers. Saut, stirring occasionally, for 8 minutes, until vegetables are golden. Add garlic and saut, stirring constantly for another 30 seconds.
  
  
• Stir in sweet potatoes, peanuts, tomatoes, and juice, tomato paste, chiles and liquid, chili powder, cumin and sugar.
  
  
• Bring to a boil, then reduce the heat to low immediately and simmer gently, stirring until the sweet potatoes are just tender. Halfway through the cooking process, adjust the seasonings, adding more chili powder and cumin if desired. Season to taste with salt and pepper and serve.

Nutrition per serving: 385 Calories, 15 gm total fat (2 gm saturated fat), 55 gm carbohydrate (3.5 carb choices per serving), 11 gm protein, 8 gm dietary fiber, 409 mg sodium.

Sweet Potato and Apple Saute

4 servings

Ingredients:

2 Tablespoons canola oil
1 pound sweet potatoes, peeled and coarsely shredded
1 Golden Delicious apple, peeled, cored and coarsely shredded
1/4 cup orange juice
1/2 teaspoon ground cinnamon
1/4 teaspoon ground ginger
Salt and freshly ground black pepper, to taste

Directions:

• In large nonstick skillet, heat oil over mediumhigh heat. Add sweet potatoes. Saut, stirring occasionally until potatoes start to soften, about 4 minutes. Add apple, orange juice, cinnamon and ginger.
  
  
• Cook, stirring occasionally, until potatoes are tender but not too soft, about 4 minutes.
  
  
• Season with salt and pepper. Serve hot or lukewarm.

Nutrition per serving: 206 calories, 7 gm. total fat (<1 g. saturated fat), 35 g. carbohydrates (2 carb choices per serving), 2 g. protein, 3 g. dietary fiber, 15 mg. sodium.

Julie Paff, RD, LD
Seton Diabetes Education Center
5555 North Lamar Blvd., Building D, Suite 125
Austin, TX 78751

Phone: (512) 324-1891

Julie sees patients at Seton Medical Center Williamson, GoodHealth Commons and Seton Southwest Hospital. She has worked as a Registered Dietitian for 30 years. She has a special interest in all aspects of diabetes management, heart disease, chronic disease management, with emphasis in Type 2 diabetes, cardiovascular disease and pre-diabetes.

Seton Diabetes Education Program

Seton Diabetes Education Program empowers individuals with diabetes to manage their disease over the course of a lifetime. Program participants can expect to learn skills and self-management strategies to manage blood sugar and reduce the risk of complications with the changing needs of disease management. Seton Diabetes Education wants to assure that all persons with diabetes or at risk of diabetes are aware of services to support health. Please contact us if you have questions or would like to learn more about the program at (512) 324-1891 or email diabeteseducation@seton.org.