Sweet Potatoes

Despite their naturally sweet taste and highly nutritive quality – far surpassing that of the common white-baking “potato” – sweet potatoes have had a hard time standing their own ground. Given their namesake, they are often mistaken as the common “potato.” But as members of the morning glory genus (Ipomoea), they are only very distantly related to the common “Irish” potato and most significantly, they are not members of the nightshade family.(1) (See posting on the adverse affects of nightshades here). In addition, the bright orange varieties of sweet potatoes are often mistaken as yams; yet again, these two root vegetables are very distinct.(2) Sweet potatoes are often marketed as “yams” in the U.S. which furthers the confusion. However, the USDA now requires that sweet potatoes labeled as yams also be labeled as sweet potatoes.(3)

Sweet potatoes grow underground as tubers, which form out of the roots of a perennial vine. They are rich in beta carotene (especially the orangish varieties), complex carbohydrates, dietary fiber and contain moderate levels of potassium and vitamins B6 and C. (4) The sweet potato has ranked highest in nutritional value compared to other vegetables when comparing fiber, complex carbohydrates, protein, beta carotene, Vitamin C, iron and calcium – far above the common potato. (5) They have been used medicinally to treat diabetes, parasites and asthma. (6) With respect to diabetes, despite being “sweet” they are believed to be a beneficial food as studies on animals have revealed that they help stabilize blood sugar levels and to lower insulin resistance. (7)

While there are numerous varieties of sweet potatoes, they can be categorized into two dominant types: the paler-skinned sweet potato has a light yellowish skin and a pale yellow to whitish flesh. It is not as sweet, and has a relatively dry, texture much like the white baking potato. The darker or reddish skinned variety, often mistaken for a “yam”, has a thicker skin and a orangish flesh with a moist texture. When in doubt, you can easily tell the difference between a yam and a sweet potato by looking at the ends. The sweet potato has pointy ends, while the yam will have rounded ends.(8)

Sweet potatoes are native to South America, and are believed to have been domesticated there at least 5,000 years ago.(9) While they thrive in tropical and subtropical climates, they do achieve some success in cooler climates of the Northern Hemisphere. (10) They can be grown as a summer crop in temperate areas such as the northern U.S. Sweet potatoes can keep for up to six months, so they can be eaten well through the winter.(11)

Sweet potatoes used to be quite a staple in the U.S., especially in the Southeast, but in the last century they have been largely replaced by the common white potato.(12) This isn’t surprising with the onset of monoculture; and, of course, the proliferation of McDonald’s and their “supersize me” french fries (McDonald’s is the largest purchaser of potatoes in the U.S., along with beef, pork and apples).(13) The zealous foodies of France gave sweet potatoes a try, but ultimately the common potato won over.(14) Maybe it’s the texture, or the color, or the sweeter taste? Who knows. I for one love cooking with sweet potatoes and have found that they are a perfect substitute for potatoes in every way. So if like me, you are wanting to limit your intake of nightshades, but don’t want to miss out on the many yummy starchy-like potato dishes, then sweet potatoes are your answer!

1. Vegetables, Herbs and Fruit: An Illustrated Encyclopedia – Biggs, Matthew (2009)
2. http://homecooking.about.com/od/howtocookvegetables/a/sweetpotatodiff.htm
3. Ibid.
4. Biggs, supra
5. http://en.wikipedia.org/wiki/Sweet_potato
6. Edible: An Illustrated Guide to the World’s Food Plants – National Geographic (2008)
7. http://en.wikipedia.org/wiki/Sweet_potato
8. http://homecooking.about.com/od/howtocookvegetables/a/sweetpotatodiff.htm
9. http://en.wikipedia.org/wiki/Sweet_potato
10. Biggs, supra
11. http://en.wikipedia.org/wiki/Sweet_potato
12. National Geographic, supra
13. Fast Food Nation – Eric Schlosser (2001)
14. Biggs, supra