History and Nutritional Value of Sweet Potatoes and Yams

The sweet potato is only very distantly related to the yam, and is actually a type of morning glory.

Historians say real Yams are native to Africa and Asia. They have a very mild, nearly tasteless flavor. According to historians, sweet potatoes in the US probably became known as yams as early as the 1600s, when slaves captured from Africa were introduced to the southern sweet potato, and compared it to the vegetable in their homeland they called a word that sounded like "yam."

However, botanists say yams are grown only in tropical regions and were first discovered in the Caribbean. Whichever group is right about the history of the yam, it is rarely sold in the United States.

The sweet potato is only very distantly related to the yam, and is actually a type of morning glory. While the term yam encompasses many different species, sweet potato varieties all have vary similar nutritional value and health benefits because they are all genetically quite similar.
 
In researching the history of the sweet potato, one version said Columbus brought them to America after they made their way to Europe from Asia. But native american oral history and archeological evidence in the US suggests they have been cultivated as a food crop in the northeasterm United States for over a thousand years.

The tuber marketed in the US under the name Yam is really just another variety of sweet potato, and is, in fact, not a yam at all. It's really the northern sweet potato.

Nutritional Value of Sweet Potatoes and Yams:

Sweet potatoes have a reputation among health food advocates as one of the most densely nutritious (but surprisingly low-calorie) foods on the market, at 117 calories per serving.

Sweet potatoes are an excellent source of key nutrients such as vitamins A and C, foliate, iron, copper, calcium and fiber. Packed with beta carotene and vitamin A, one serving of sweet potatoes provides more beta carotene than 23 cups of broccoli and more fiber than oatmeal. They contain practically no fat or cholesterol.

It is the meat of the sweet potato that is so nutritious. It is not necessary to eat the peeling to get all the vitamins, as is necessary with the white potato.

Sweet potatoes are a much better choice than the regular white potato that is a staple in so many American diets. A white potato is very high in starches and carbohydrates, making them a bad choice for diabetics because of the quick rise in insulin levels they create because the carbohydrates break down quickly into simple sugars.

However, in contrast, sweet potatoes metabolize more slowly, so they can be eaten by diabetics, and have no negative effects on overall health.

Eye doctors highly recommend sweet potatoes because of the excellent levels of vitamin A which studies have shown improve eye health. One sweet potato contains nearly eight times an adult's daily need of this important vitamin, and, because the vitamin is fat-soluble rather than water-soluble, the body can store it for later use. Many Americans are deficient in this important vitamin.

The high levels of fiber and vitamin C help to improve the digestive tract and strengthen the immune system.

The southern sweet potato contains several other vitamins and minerals in amounts not found in the tuber we call a yam (or more correctly, the northern sweet potato). Compared to yams, sweet potatoes contain significantly higher amounts of calcium, iron, and vitamin E, and they have twice as much protein per serving. While this may make the sweet potato look like a hands-down winner, the yam also has its own impressive nutritional values, some of which the sweet potato lacks.

Omega-3 fatty acids have the ability to do everything from prevent heart disease to increasing brain stamina. Although both the yam and the sweet potato are low-fat foods, the ratio of essential fatty acids is better in the yam compared to the sweet potato. Sweet potatoes contain less omega-3 fats than yams, and have nearly twice as many omega-6 fats, which are known to inhibit the body's ability to make use of the omega-3's. When it comes to fatty acids, yams are better than sweet potatoes.

Sweet potatoes contain massive amounts of anti-inflammatory compounds, which are very important in the health of people with IBS, arthritis, gout, and other inflammation-related diseases. Yams, on the other hand, not only lack these anti-inflammatory nutrients, but actually contain a number of compounds that aggrevate these conditions. However, their inflammation-causing tendencies are still less severe than many other foods.

Both the sweet potato and yam offer special health benefits to people with diabetes. Both have very low glycemic indexes, with the gylcemic load in the sweet potato at 17, and the yam at 16. The sweet potato was found by one animal study to actually lower glycemic resistance in those with diabetes-- preliminary evidence that long-term consumption of these miracle-vegetables can actually help to fight against diabetes symptoms.

Other health benefits found in both the sweet potato and yam include similarly high concentrations of key minerals. The yam and sweet potato are both loaded with potassium, magnesium, and phosphorous, as well as several so-called trace minerals: selenium, zinc, and copper, but the sweet potato comes in slightly higher in these nutrients than the yam.

(Part 1) Candied Sweet Potatoes (Part 2) History and Nutritional Value of Sweet Potatoes & Yams