The Difference Between Sweet Potatoes and Yams
Sweet potatoes and yams are often considered to be the same tuber vegetable; although technically they are not even related, nor do they share the same flavor, consistency, and nutritional profile. Native to Africa, yams are close relatives of lilies and grasses, while sweet potatoes belong to the morning glory family. They originated in the other side of the world, in South and Central America.
Yams are monocots (plants which have one embryonic seed leaf) from the Dioscoreaceae family. Sweet potatoes are dicots (plants with two embryonic seed leaves) of the Convolvulacea family. Yams, which come in a similar range of colors as sweet potatoes – whitish yellows, purples, oranges, and reds – are starchier, more mealy, and can grow to be several times larger than sweet potatoes.
Why the confusion? In North America, where sweet potatoes are the tuber vegetable of choice, people needed to differentiate between starchy, dry sweet potatoes, and sweeter, moist sweet potatoes. In an attempt at simplification, they used the term yam to describe many types of sweet potatoes, thus we have garnet yams and jewel yams that are not yams at all, but sweet potatoes.
Beauregards, as well as garnet yams and jewels all have a deep orange to red flesh which is incredibly sweet and creamy, and packed with beta-carotene, the phytonutrient of orange-pigmented foods. Nancy Hall and juicy yellow are two types of sweet potatoes which have a tan skin and a yellow flesh, with a more crumbly texture. Okinawan sweet potatoes are much drier, and not nearly as sweet. Their rich, purple skin is a good source of anthocyanins – potent antioxidants found in purple or bluish foods.
Sweet Potatoes and Health
There are a number of health benefits of sweet potatoes. This is because the nutrition of sweet potatoes is high, while the calorie content is low. One potato provides more than 200% of the recommended daily requirement for vitamin A through beta-carotene. Vitamin A promotes healthy skin and eyes, but it also works as an antioxidant, neutralizing free radicals before they can damage cells. Sweet potatoes are also a good source of the main water-soluble antioxidant, vitamin C, which is necessary for the immune system and cellular regeneration. This tuber vegetable also appears to provide antioxidant activity from root storage proteins.
Vitamin B6, potassium, iron, copper, and manganese are all part of the nutrition of sweet potatoes. These nutrients protect the heart, nourish the body, and help to produce energy. Vitamin B6 helps to transform homocysteine into harmless molecules – high levels of homocysteine in the body are associated with heart disease. Potassium regulates blood pressure levels, while iron is needed for the circulation of oxygen-rich blood. Copper is needed for a number of enzyme reactions, energy production, and growth; manganese is primarily used to maintain healthy bones. Sweet potatoes also supply a significant amount of fiber to help the body rid itself of toxins. All of this for less than two hundred calories, making the sweet potato an ideal food for anyone concerned with their health.
How Do You Cook Sweet Potatoes?
Sweet potatoes can be served as a side dish, part of a main course, or the focal point of dessert. They can be found in the grocery store all year round, although if you can’t find organic or farmer’s market sweet potatoes, don’t eat the skin which may have been treated with dye or wax. Store this tuber vegetable in a cool dry place, but not in the refrigerator.
Baking sweet potatoes is the classic preparation method. Pierce the skin, and then cook in a 375 degree oven for one hour, or until soft. Add butter, or pecans and brown sugar. Another way to enjoy sweet potatoes is to fry slices in an inch of canola oil until soft, then drain, and top with sour cream.
Add steamed sweet potato cubes to corn chowder, rice pilaf, or sauteed vegetables, to add the unique sweet flavor as well as the nutrition of sweet potatoes. For a simple dessert, puree sweet potatoes with bananas and honey, and top with whipped cream. The possibilities are endless with sweet potatoes. Are sweet potatoes good for your health? Should they be part of your regular diet? Definitely.