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The types of sweet potatoes in a market all belong to one species, Ipomoea batatas, according to Illinois Extension and the University of Maryland Extension, which place it in the morning glory family (Convolvulaceae) and say the true yam, a Dioscorea species, is an unrelated plant. Within that species, the Library of Congress lists skin colors from white to yellow, red, purple or brown and flesh colors from white to yellow, orange or orange-red. This guide walks through those sweet potato varieties with extension sources and compares cooked forms, true yams and a baked potato with USDA FoodData Central values; our sweet potato guide covers the vegetable on its own and our yam guide covers the true yam.
Peptide Labs does not sell foods. This article is general nutrition information, not medical advice.
Key Takeaways
- Illinois Extension and the University of Maryland Extension identify sweet potatoes as Ipomoea batatas, in the morning glory family, and the true yam as an unrelated Dioscorea species.
- The Library of Congress says sweet potato varieties are classed as firm or soft, and that the soft varieties are the ones often labeled as yams in the United States.
- Illinois Extension says orange-fleshed varieties are the most common today, while some white or very pale yellow-fleshed types are still available.
- Per 100 grams, baked sweet potatoes list about 961 micrograms RAE of vitamin A in USDA data, against about 6 micrograms RAE for cooked true yams and an FDA Daily Value of 900 micrograms RAE.
Types of sweet potatoes by flesh color and texture
The Library of Congress says the skin of sweet potatoes ranges from white to yellow, red, purple or brown, and the flesh from white to yellow, orange or orange-red. The Library of Congress adds that the varieties are classified as firm or soft: firm ones stay firm when cooked, while soft ones become soft and moist.
- Orange-fleshed, moist types: Illinois Extension says orange-fleshed varieties are the most common today, and the University of Maryland Extension says cultivars with moist flesh predominate in the United States and are sometimes called yams.
- White and pale yellow-fleshed types: Illinois Extension says some white-fleshed types are still available, and Clemson Cooperative Extension describes one white- to yellow-fleshed cultivar as not very sweet and prepared much like a standard white potato.
- Purple-skinned types: Clemson Cooperative Extension describes a purple-skinned cultivar with pale flesh that is less creamy and flakier than other sweet potatoes, with a nutty flavor.
- Drier types: the University of Maryland Extension says Japanese and Korean sweet potatoes are drier, store better and are becoming more popular in Maryland.
- Leaves and shoots: the University of Maryland Extension says young leaves and shoots can be eaten as greens, and Illinois Extension says both the roots and the tender shoots are eaten in tropical and subtropical countries.
Sweet potatoes versus true Dioscorea tubers
The Library of Congress says yams and sweet potatoes are both flowering plants but are not related botanically: yams are monocots in the Dioscoreaceae, or yam family, while sweet potatoes are dicots in the morning glory family. The same Library of Congress page describes yams as closely related to lilies and grasses and as starchier and drier than sweet potatoes. The University of Maryland Extension adds that sweet potatoes are storage roots, not tubers, while the true yam is grown primarily in tropical and semitropical areas for its tubers, and Illinois Extension says the two names are often used interchangeably in the marketplace.
Both crops appear in our list of starchy vegetables, and our guide to root vegetables covers the wider group.
Cooked sweet potatoes in USDA data
USDA FoodData Central SR Legacy has no separate orange, white or purple-skinned entries, so its generic entries stand for the group. The table lists raw, baked, boiled, frozen and canned sweet potatoes per 1 cup, using SR Legacy portions, ranked by vitamin A. Each percent Daily Value (%DV) uses the FDA Daily Values for adults and children 4 and older: 28 grams of dietary fiber, 4,700 milligrams of potassium, 90 milligrams of vitamin C, 900 micrograms RAE of vitamin A and 1.7 milligrams of vitamin B6.
| Sweet potatoes (USDA FDC ID) | Serving | Calories | Carbohydrate | Fiber | Potassium | Vitamin C | Vitamin A | Vitamin B6 |
|---|---|---|---|---|---|---|---|---|
| Sweet potato, boiled without skin (168484) | 1 cup mashed, 328 g | 249 | 58.1 g | 8.2 g (29%) | 754 mg (16%) | 42.0 mg (47%) | 2,581 mcg RAE (287%) | 0.54 mg (32%) |
| Sweet potato, baked in skin, flesh (168483) | 1 cup, 200 g | 180 | 41.4 g | 6.6 g (24%) | 950 mg (20%) | 39.2 mg (44%) | 1,922 mcg RAE (214%) | 0.57 mg (34%) |
| Sweet potato, frozen, baked (169307) | 1 cup cubes, 176 g | 176 | 41.2 g | 3.2 g (11%) | 664 mg (14%) | 16.0 mg (18%) | 1,836 mcg RAE (204%) | 0.33 mg (19%) |
| Sweet potato, canned, mashed (169305) | 1 cup, 255 g | 258 | 59.1 g | 4.3 g (15%) | 536 mg (11%) | 13.3 mg (15%) | 1,109 mcg RAE (123%) | 0.60 mg (35%) |
| Sweet potato, canned, vacuum pack (168485) | 1 cup mashed, 255 g | 232 | 53.9 g | 4.6 g (16%) | 796 mg (17%) | 67.3 mg (75%) | 1,017 mcg RAE (113%) | 0.48 mg (29%) |
| Sweet potato, raw (168482) | 1 cup cubes, 133 g | 114 | 26.8 g | 4.0 g (14%) | 448 mg (10%) | 3.2 mg (4%) | 943 mcg RAE (105%) | 0.28 mg (16%) |
Per cup, boiled sweet potatoes without skin list about 2,581 micrograms RAE of vitamin A in USDA data and baked sweet potatoes about 1,922 micrograms RAE, against an FDA Daily Value of 900 micrograms RAE. Cup weights differ: USDA weighs a cup of mashed boiled sweet potatoes at 328 grams and a cup of baked flesh at 200 grams. The canned vacuum-pack entry lists about 67.3 milligrams of vitamin C per cup in USDA data, against 39.2 milligrams for the baked cup. Candied and syrup-packed products differ, and the Nutrition Facts label is the figure for a packaged product. Our guide to beta carotene and our list of vitamin A foods cover the pigment and the vitamin.
Sweet potatoes, Dioscorea tubers and potatoes compared
SR Legacy also lists true yams, a baked potato and the raw leaves of sweet potatoes. The table lists them per 100 grams with SR Legacy’s common portion alongside, ranked by vitamin A, with the same FDA Daily Values plus 120 micrograms of vitamin K.
| Food (USDA FDC ID) | Serving | Common portion (USDA) | Calories | Carbohydrate | Fiber | Potassium | Vitamin C | Vitamin A | Vitamin K |
|---|---|---|---|---|---|---|---|---|---|
| Sweet potato, baked in skin, flesh (168483) | 100 g | 1 medium, 114 g | 90 | 20.7 g | 3.3 g (12%) | 475 mg (10%) | 19.6 mg (22%) | 961 mcg RAE (107%) | 2.3 mcg (2%) |
| Sweet potato, raw (168482) | 100 g | 1 cup cubes, 133 g | 86 | 20.1 g | 3.0 g (11%) | 337 mg (7%) | 2.4 mg (3%) | 709 mcg RAE (79%) | 1.8 mcg (2%) |
| Sweet potato leaves, raw (169303) | 100 g | 1 cup chopped, 35 g | 42 | 8.8 g | 5.3 g (19%) | 508 mg (11%) | 11.0 mg (12%) | 189 mcg RAE (21%) | 302.2 mcg (252%) |
| Yam, raw (170071) | 100 g | 1 cup cubes, 150 g | 118 | 27.9 g | 4.1 g (15%) | 816 mg (17%) | 17.1 mg (19%) | 7 mcg RAE (1%) | 2.3 mcg (2%) |
| Yam, boiled or baked (170072) | 100 g | 1 cup cubes, 136 g | 116 | 27.5 g | 3.9 g (14%) | 670 mg (14%) | 12.1 mg (13%) | 6 mcg RAE (1%) | 2.3 mcg (2%) |
| Potato, baked, flesh and skin (170093) | 100 g | 1 medium, 173 g | 93 | 21.1 g | 2.2 g (8%) | 535 mg (11%) | 9.6 mg (11%) | 1 mcg RAE (0%) | 2.0 mcg (2%) |
Per 100 grams, raw true yams list about 7 micrograms RAE of vitamin A in USDA data and baked potatoes about 1 microgram RAE, against 709 micrograms RAE for raw sweet potatoes. Raw yams list more potassium in USDA data, about 816 milligrams per 100 grams against 337 milligrams for raw sweet potatoes. The leaves stand apart: the raw leaves of sweet potatoes list about 302.2 micrograms of vitamin K per 100 grams in USDA data, against 1.8 micrograms for the raw roots. Our guide to types of potatoes covers the potato side of the bin, and our guide to types of kale covers another leafy crop.
Curing and keeping quality
- Curing: the University of Maryland Extension says curing converts starch to sugar and helps mend cuts in the skin of the roots, and that the sugar content slowly increases in storage.
- Cool, not cold: Clemson Cooperative Extension says sweet potatoes belong in a cool location after curing, never below 50 degrees Fahrenheit and never in the refrigerator, because colder temperatures cause off-flavors and possible rot.
- Handling: Illinois Extension says sweet potatoes should be handled as little as possible to avoid scuffing and bruising.
The Dietary Guidelines for Americans, 2020-2025, list sweet potatoes with calabaza and carrots as examples of red and orange vegetables.
Frequently Asked Questions
What are the main types of sweet potatoes?
The Library of Congress groups them as firm or soft and lists flesh colors from white to yellow, orange or orange-red; Illinois Extension says orange-fleshed varieties are the most common today.
Are sweet potatoes the same as a yam?
No. Illinois Extension and the University of Maryland Extension say the true yam, a Dioscorea species, is unrelated to sweet potatoes, which are Ipomoea batatas in the morning glory family.
Why do some labels call them by another name?
The Library of Congress says the soft, moist varieties of sweet potatoes are the ones often labeled as yams in the United States.
Which type lists the most vitamin A in USDA data?
USDA SR Legacy has no separate entries for flesh colors; per cup, boiled sweet potatoes without skin list about 2,581 micrograms RAE, against an FDA Daily Value of 900 micrograms RAE.
Are the leaves edible?
The University of Maryland Extension says young leaves and shoots can be eaten as greens, and USDA SR Legacy lists raw leaves at about 302.2 micrograms of vitamin K per 100 grams.
How do purple-skinned types differ?
Clemson Cooperative Extension describes a purple-skinned cultivar with pale flesh that is less creamy and flakier than other sweet potatoes, with a nutty flavor.
Questions about a label? Contact us or read our Buyer’s Guide. Food comes first; follow the label and ask a healthcare provider before starting a supplement, especially if you take medicines, are pregnant or have a health condition. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure, or prevent any disease.
Last reviewed October 2026.
Related guides: Types of Kale: Curly, Lacinato and Red Russian Compared, Sweet Potato Nutrition: Calories, Vitamin A and Sweet Potato vs Potato, Types of Potatoes: Russet, Red, White, Yellow and Fingerling, Root Vegetables List: True Roots, Tubers and USDA Values.