By Julie Garden-Robinson, Food and Nutrition Specialist

NDSU Extension Service

My sister and I stared at the pale yellow vegetables and looked at each other with confused expressions. My husband, who had just returned with the vegetables from the grocery store, noticed our silent interaction.

“You said you wanted sweet potatoes. These are sweet potatoes,” my husband said.

“They don’t look like sweet potatoes. They’re supposed to be orange,” I said.

“The orange ones were labeled yams and these were labeled sweet potatoes. I even looked them up in the catalog at the store,” he added.

With all this careful checking at the store, I think he was trying to avoid being featured in my nutrition column.

“OK, I guess I wanted yams, then,” I said, although I wasn’t completely convinced.

The seed of a column was taking root in my mind.

Curious about the differences between yams and sweet potatoes, I looked up some information. After reviewing several articles, I can see why confusion surrounds sweet potatoes and yams.

By the way, my husband had brought home sweet potatoes as requested.

Sweet potatoes have flesh that can vary in color from pale yellow to dark orange. The darker-skinned vegetables with orange flesh often are labeled yams because that is what people usually call them in the U.S.

However, if a vegetable is labeled a yam, the U.S. Department of Agriculture says it also should be labeled a sweet potato.

Technically, though, sweet potatoes and true yams are two different things. They’re not even relatives. A sweet potato is a root, so it is more like a carrot than a potato.

True yams are relatively rare in U.S. grocery stores. The orange-fleshed sweet potato variety primarily is grown in the southern U.S., while the true yam is a starchy vegetable grown in the Caribbean and Africa.

In fact, the name yam comes from the African word “nyami,” which means “to eat.”

Sweet potatoes have a smooth skin and an elongated shape, while true yams have rough, scaly skin and can be very large. True yams can grow to be 7 feet long.

In other words, the next time I ask my husband to pick up a yam, I might end up with a 7-foot vegetable. I will know for sure, however, that it is not a sweet potato.

Regardless of what you call them, enjoy sweet potatoes more often. They are an excellent source of beta carotene, which our bodies convert to vitamin A. This vitamin helps keep our skin healthy, among many other functions.

Fiber-rich sweet potatoes also contain vitamin C and B vitamins, plus some calcium and iron. Even though they taste sweet, they have just 100 calories per 3.5-ounce portion, similar to a regular potato.

Sweet potatoes can be baked, boiled, fried, cooked in a microwave or grilled. Some people also like to deep-fry them as chips, although that’s a sure way to increase the fat content and short-change the nutritional benefits.

Add a little variety to your diet. Try this tasty recipe from the Pennsylvania Nutrition Education Network.

Baked Sweet Potatoes and Apples

5 medium-sized, cooked sweet potatoes (dark orange-fleshed variety)

4 apples

1/2 c. brown sugar

1/2 tsp. salt

1/4 c. margarine or butter

1 tsp. nutmeg

1/4 c. hot water

2 Tbsp. honey

Boil the sweet potatoes in water until they are almost tender. After the sweet potatoes cool, peel and slice them. Preheat oven to 400 degrees. Peel the apples, remove the cores and slice. Spray a casserole dish with nonstick cooking spray. Put a layer of sweet potatoes on the bottom of the dish. Add a layer of apple slices. Sprinkle with sugar, salt and tiny pieces of margarine or butter. Repeat layering process, adding some sugar, salt and margarine to each layer. On the top layer, sprinkle the rest of the brown sugar and margarine. Sprinkle with nutmeg. Mix the hot water with honey. Pour over the top layer. Bake for about 30 minutes or until apples are tender.

Makes eight servings. Each serving has 225 calories, 6 grams (g) of fat, 44 g of carbohydrate, 4.5 g of fiber and more than a full day’s recommendation for vitamin A (as beta carotene).

(Julie Garden-Robinson, Ph.D., L.R.D., is a North Dakota State University Extension Service food and nutrition specialist and associate professor in the Department of Health, Nutrition and Exercise Sciences.)

NDSU Agriculture Communication