Purple Sweet potatoes are the edible tubers of the sweet potato plants. Compared to their orange counterparts, purple sweet potatoes are much higher in vitamin A than other varieties of sweet potatoes. Each cup of purple sweet potatoes contains only about 114 calories, with 2 g protein, 27 g carbohydrates and no fat or cholesterol. Each cup of purple sweet potatoes provides almost 375% of the RDA for Vitamin A.
Stokes is probably the biggest local (US) supplier of purple sweet potatoes. Along with the high Vitamin A content, purple sweet potatoes are loaded with anthocyanins, which cause the rich purple color, and other polyphenolic compounds which have antioxidant properties. Purple sweet potatoes are also diabetic friendly, with a lower glycemic index than white potatoes.