There are almost 400 hundred varieties of sweet potato, including what is commonly known in the US as a yam. A true yam is the root of the Dioscorea genus of plants, and the word yam is derived from the African term for the root, nyami.
All potatoes, including sweet potatoes, originate from South America, and are one of the oldest vegetables known.
Columbus was the man to introduce the sweet potato to American shores, and Spanish and Portuguese explorers to other parts of the world. Health Benefits of Sweet Potatoes
* Vitamins Sweet potatoes are a good source of vitamins C and B6.
* Beta-Carotene Sweet potatoes are an excellent source of beta-carotene, with the darker varieties having a higher concentration. Beta-carotene is converted in the intestine into Vitamin A, which is essential for normal vision as well as proper bone growth, healthy skin, and protection of the mucous membranes of the digestive, respiratory, and urinary tracts against infection. Keratomalacia is an eye condition resulting from a severe deficiency of Vitamin A. In some developing countries, vitamin A deficiency in the diet and associated keratomalacia are a major cause of childhood blindness. In many developing countries, sweet potato is a secondary staple food and may play a role in controlling vitamin A deficiency.
* Glycemic Index The Glycemic Index (GI) is a scale that ranks carbohydrate-rich foods by how much they raise blood glucose levels compared to a standard food. Although different varieties of sweet potato have different GI values, it is listed in the South beach Diet as having a low GI of 54. Research has demonstrated that lowering the glycemic load of the diet appears to be an effective method of promoting weight loss.
* Diabetes The white-skinned sweet potato has been shown to improve insulin sensitivity in patients with type 2 diabetes. In a study of 18 type 2 diabetic patients, the sweet potato consistently improved metabolic control by decreasing insulin. These results indicate that the white-skinned sweet potato could potentially play a role in the treatment of type 2 diabetes.
Nutritional value per 100 g (3.5 oz) Energy 360 kJ (86 kcal) Carbohydrates 20.1 g Starch 12.7 g Sugars 4.2 g Dietary fibre 3.0 g Fat 0.1 g Protein 1.6 g Vitamin A equiv. 709 μg (79%) - beta-carotene 8509 μg (79%) - lutein and zeaxanthin 0 μg Thiamine (Vit. B1) 0.1 mg (8%) Riboflavin (Vit. B2) 0.1 mg (7%) Niacin (Vit. B3) 0.61 mg (4%) Pantothenic acid (B5) 0.8 mg (16%) Vitamin B6 0.2 mg (15%) Folate (Vit. B9) 11 μg (3%) Vitamin C 2.4 mg (4%) Calcium 30.0 mg (3%) Iron 0.6 mg (5%) Magnesium 25.0 mg (7%) Phosphorus 47.0 mg (7%) Potassium 337 mg (7%) Sodium 55 mg (2%) Zinc 0.3 mg (3%