Have you ever seen the words ‘yam’ or ‘sweet potato’ used in recipe names and displayed on farmers market signs, but wondered if these terms refer to one and the same thing? I’m sure many of us have also walked into U.S. grocery stores and seen familiar bins of red-skinned and orange fleshed tubers labelled as ‘yams’. But, are these really yams? Read on to find out if there really is a difference and learn some interesting facts about sweet potatoes and yams along the way!
Although both yams and sweet potatoes are edible starchy root tubers, there are differences not only in their genera, but also in their inner and outer appearances. First, sweet potatoes are members of the Convolvulaceae family of flowering plants, which includes the morning glory and water spinach. But, according to the North Carolina Sweet Potato Commission, “A true yam is a starchy edible root of the Dioscorea genus, and is generally imported to America from the Caribbean. It is rough and scaly and very low in beta carotene.” Besides coming from different genera, sweet potatoes tend to be sweeter than yams in taste and also vary less in terms of shape and size. On the other hand, yams tend to have a starchier, more potato-like texture, can differ internally and externally in color, and can even grow up to 5 feet (1.5 meters) long and weigh up to 100 pounds (70 kilograms)!
So when you walk into a grocery store in the United States, and see a bin of coppery-red and orange fleshed tubers labelled as ‘yams’, what are they really? These are actually sweet potatoes! Here’s how it happened. Back in the past, these ‘yams’ were labelled so originally by shippers and producers to distinguish them from the white potatoes, using the English form of the African word “nyami”. And that name stuck. Now in U.S. grocery stores, you will see the term ‘yam’ used for soft sweet potatoes that have a coppery-red skin and deep orange flesh, while those termed ‘sweet potato’ are generally firmer with golden skins and lighter colored flesh.
Nutrition-wise, sweet potatoes are a great source of vitamin A, beta-carotene (a provitamin A or precursor of vitamin A), and many other nutrients. For example, just one medium cooked sweet potato (150 grams in weight) already provides you with approximately 2 grams of protein, 3.8 grams of fiber, 40 milligrams of calcium, 347 milligrams of potassium, 1190 micrograms of vitamin A (RAE), and 14300 micrograms of B-carotene! Yams, on the other hand, are generally higher in nutrients like protein, fiber and potassium, but are much lower in vitamin A and beta-carotene content.
Did you know? Sweet potatoes actually have an ancient history and there are thousands of varieties of sweet potatoes. Depending on the specific variety of sweet potato, the flesh of sweet potatoes can also vary from white, to orange to even purple!
As you can see, although growers in the United States use the name “yam” to distinguish soft orange-fleshed sweet potatoes from the firmer white-fleshed varieties, these sweet potatoes are actually unrelated to true yams. So, as it turns out, there is more than just a name difference, and the dish we frequently serve at special occasions like Thanksgiving and Christmas is actually made from sweet potatoes, not yams! Now are you ready to enjoy a festive yet easy and healthy sweet potato dish? If you are, try this delicious Tangy Cinnamon Sweet Potato Bake!
- North Carolina Sweet Potato Commission. What is the difference between a sweet potato and a yam? http://www.ncsweetpotatoes.com/sweet-potatoes-101/difference-between-yam-and-sweet-potato/. Accessed August 1, 2022.
- Sweet Potato or Yam? Endurance Magazine. Endurancemag.com. https://www.endurancemag.com/2013/11/nutrition-sweet-potatoes/. Accessed August 1, 2022.
- Foster K. What’s the Difference Between Yams and Sweet Potatoes? www.theKitchnn.com. http://www.thekitchn.com/whats-the-difference-between-yams-and-sweet-potatoes-word-of-mouth-211176. Updated June 8, 2019. Accessed August 1, 2022.
- New World Encyclopedia contributors. Sweet potato. New World Encyclopedia. https://www.newworldencyclopedia.org/entry/Sweet_potato. April 4, 2008. Accessed August 1, 2022.
- Sweet Potato Cooked, Boiled, Without Skin. USDA FoodData Central. https://fdc.nal.usda.gov/fdc-app.html#/food-details/168484/nutrients. Accessed August 1, 2022.
- Yam, Cooked, Boiled, Drained, or Baked, Without Salt. USDA FoodData Central. https://fdc.nal.usda.gov/fdc-app.html#/food-details/170072/nutrients. Accessed August 1, 2022.)