Sweet potato - the perfect food?

By Laurel Robinson, Dietician

In the Highlands in Papua New Guinea, the wealth of a man is determined by the number of sweet potatoes in his garden patch ... the one tended by his wife. The man with the most potatoes is the most powerful in the tribe.

The sweet potato is a native American plant found by Columbus. The genus Ipomoea that contains the sweet potato also includes several garden flowers called morning glories.

Early Spanish explorers are believed to have taken the sweet potato to the Philippines and East Indies, from there it was soon carried to India, China and Malaya by Portuguese voyagers. In Asia the American origin of the plant was long overlooked, many believing it native to southern and southeastern Asia.

The sweet potato is far more important in these subtropical and tropical areas than is the Irish potato because it thrives in a hot, moist climate, while the latter requires a cool climate. It is prevalent as a food source in the warm Pacific islands, the East Indies, India, China, and is now the third most important food crop in Japan.

Ipomoea batatas - “batata” being the original Taino name, hence “potato” - is the Latin name for the sweet potato. It is commonly called a yam in parts of the United States. It's distant cousin, the true yam is of the genus Dioscorea, and is rarely seen in the U.S. and Canada but is a staple in tropical regions, where they can grow up to seven feet in length.

One baked sweet potato (3 1/2 ounce serving) provides about twice the recommended daily allowance of vitamin A, yet it contains only 141 calories, making it valuable for the weight watcher. This vegetable provides 42 percent of the Recommended Daily Allowance (RDA) for vitamin C, 6 percent of the RDA for calcium, 10 percent of the RDA for iron and 8 percent of the RDA for thiamine for healthy adults. It is low in sodium and is a good source of fiber and other important vitamins and minerals. A complex carbohydrate food source, it provides beta carotene, which may be a factor in reducing the risk of certain cancers. Despite the name “sweet,” it is actually a good food for diabetics, as preliminary studies on animals have revealed that it helps to stabilize blood sugar levels and lower insulin resistance.

In 1992, the Center for Science in the Public Interest compared the nutritional value of sweet potatoes to other vegetables. Considering fiber content, complex carbohydrates, protein, vitamins A and C, iron and calcium, the sweet potato ranked highest in nutritional value. According to these criteria, sweet potatoes earned 184 points, 100 points over the next on the list, the common potato.

Sweet potato varieties with dark orange flesh have more vitamin A than those with light colored flesh.

Culinary Uses

When buying sweet potatoes, select sound, firm roots. Handle them carefully to prevent bruising. Store in a dry, unrefrigerated bin kept at 55-60 degrees. Do not refrigerate, because temperatures below 55 degrees will chill this tropical vegetable, giving it a hard core and an undesirable taste when cooked.

Wash cured sweet potatoes and bake in a baking pan until slightly soft for about an hour, here at altitude. Eat hot or refrigerate and eat cold or at room temperature with butter and salt. You can also eat them mashed as you would a white potato.

In South America, the juice of red sweet potatoes is combined with lime juice to make a dye for cloth. By varying the proportions of the juices, every shade from pink to purple to black can be obtained.

A unique variety of sweet potato grown in New Zealand, originally grown by the indigenous Maori, is the kumara, a red/purple variety with a unique flavor due to its isolation from other varieties.

Those Papuans ain't so crazy after all.

Laurel Robinson is a trained Dietitian who also practices NLP, a type of pro-active psychotherapy. She runs seasonal group cleansing classes in the spring and fall, and is available for private nutritional and weight-loss coaching, cleansing programs or eating-related psychotherapy at her office on Main Street. “Food Fore Thought” 708-0356.