Last week I mentioned that I had looked into a potato that wasn't a potato at all, and that would be the sweet potato. Potatoes and sweet potatoes belong to completely different plant families, despite both being starchy, tuberous root vegetables with somewhat similar uses in cooking. 

A Potato, botanical name Solanum tuberosum, is in the Solanaceae or Nightshade family, with other vegetables like tomatoes, peppers, eggplant, and tobacco. They are what is known as a stem tuber as potatoes grow from underground stems or stolons that swell into tubers. Sweet potatoes on the other hand, botanical name Ipomoea batatas, is part of the Convolvulaceae or morning glory family. Sweet potatoes develop from the roots (root tubers). Their plants produce vines with flowers similar to morning glories. 

Years ago, I had a customer come into the store in late September after a hard frost with what they thought was a real problem. They were cleaning out their window boxes at the end of the season and found large tuberous growths in the soil. What they really had was sweet potatoes that had grown from the colorful sweet potato vines they bought back in the spring to hang down over the edges of the boxes. The ornamental sweet potato vines that we sell in the spring for window boxes and planters are just colorful versions of regular sweet potatoes. Given the right conditions they will produce sweet potatoes just as if you planted them in the garden. 

Sweet potatoes have many of the same health benefits as white potatoes with a few exceptions. They are a vitamin A powerhouse with extremely high beta-carotene levels being converted to vitamin A, often greater than 100% of the daily allowance per medium sweet potato, supporting vision, immune function, skin health, and growth. Antioxidants and anti-inflammatory properties from Beta-carotene, vitamin C, and polyphenols combat oxidative stress and may reduce risks of chronic diseases like cancer and heart disease. Higher in fiber than regular potatoes, sweet potatoes support regularity, acts as a prebiotic for improved gut health, and helps lower cholesterol. Also, with a lower glycemic index than white potatoes fiber helps moderate rises in blood sugar. 

Potassium, fiber, and antioxidants contribute to better cholesterol levels and blood pressure. And sweet potatoes are a good source of manganese. Vitamin C and manganese combined may support brain health and provide sustained energy. Sweet potato shouldn't be just for Thanksgiving as this is a vegetable that gives much more than it takes. One last thing, sweet potatoes are not “yams.” I always thought that a yam was a southern slang word for sweet potato, but it is not. A yam is not even related to a sweet potato. They are completely different vegetables from unrelated plant families. In the United States and many other places, the terms are often used interchangeably due to historical marketing from the early twentieth century, but this is technically incorrect. 

Yams, native to Africa and Asia, are rough, scaly, with a bark-like brown skin, and a long cylindrical shape that can grow six feet or more and weigh over one hundred pounds. It's flesh usually white, ivory, or pale yellow with a starchy, dry, and neutral/mild flavor (not sweet when cut) becomes slightly sweeter when cooked but stays firmer than sweet potatoes. Most people have never had a real yam. Even the famed southern dish, candied yams, was really made with sweet potatoes. You'll only be able to find real yams in ethnic grocery stores as most major grocery stores will only have what is labeled as a “yam sweet potato,” which isn't a yam at all.