First things first: A sweet potato is not a yam, and a yam is not a sweet potato. Sweet potatoes are native to the Americas, while yams were grown in West Africa. Since the two vegetables look so familiar, folks just got used to calling sweets yams. Also, yams aren't sweet.
Secondly, sweet potatoes and white potatoes are not in the same family of plants, but yams and potatoes are. Sweet potatoes are actually a member of the morning glory family, with edible, nutrient-storing roots. White potatoes and yams are tubers.
Finally, sweet potatoes knock white potatoes out of the nutrition park. Sweet potatoes are incredibly heart healthy, boasting high levels of fiber, Beta Carotene and vitamins B6 and D. They also contain iron, potassium, and magnesium. Sweet potatoes have a low glycemic index and can actually help diabetics keep their blood sugar levels in the safe range. By comparison, white potatoes have a high glycemic index.
Not only do sweet potatoes blow white potatoes out of the water in terms of overall nutrition, they are lower in calories and taste delicious with very little adulteration. Plus, you can eat the greens AND the roots.
I could go on and on about this beloved morning glory root. We cook sweets all sorts of ways at my house, so I have many recipes. I also highly recommend that you take a look at Hugh Acheson’s latest contribution to this month’s print edition of Organic Life magazine, which is a wonderful sweet potato snapshot and includes a recipe for sautéed sweet potato greens.
For more sweet potato 101, check out North Carolina State University's sweet potato history site.
Now go out and get some beautiful sweets and enjoy!