Sweet potatoes and yams are both flowering plants (angiosperms), but from the botanical point of view they are not related. Yams belong to the yam family (Dioscoreaceae) and are monocotyledons (plants with one embryonic seed leaf). On the other hand, sweet potatoes, which are often erroneously called "yams", are dicotyledons (plants having two embryonic seed leaves) and belong to the morning glory (Convolvulacea) family.
Sweet potatoes (scientific name Ipomoea batatas) are available in several varieties and all of them belong to the morning glory family. The color of sweet potato skin may differ from white to yellow, brown, purple or red. In addition, the flesh of sweet potatoes may also differ from white to yellow, orange-red or just orange. Sweet potatoes are classified into two groups - "soft" or "firm". The soft variety of sweet potatoes become moist and softer after cooking, while those belonging to the "firm" variety remain firm even after cooking. Many people in the United States often mistake the soft variety of sweet potatoes as yams.
Sweet potatoes are basically tuberous roots that are usually large, having a sweet flavour and starchy. This is a root vegetable. Aside from the root vegetable, even the tender leaves and shoots of this plant are occasionally consumed by people as they eat greens. This root vegetable has its origin in the tropical areas in the two Americas. There are about 50 genera and over 1,000 species of Convolvulacea. Among all these species, only I. batatas is the sole plant that is significant, while some other species, such as I. aquatic, of this plant family are used in some regions. At the same time, several species of Convolvulacea are poisonous. Although sweet potatoes do not have any botanical relation with yams, they have a distinct relation to the common potato (scientific name Solanum tuberosum). It is worth mentioning that sweet potatoes are not members of the nightshade family.
Aside from the sweet potato, the genus Ipomoea also comprises many garden flowers known as morning glories. However, the term morning glory is generally not applicable to sweet potatoes or Ipomoea batatas. People also grow a number of Ipomoea batatas cultivars as ornamental plants. However, in the context of horticulture, one may use the term tuberous morning glory.
The sweet potatoes are perennial vines. This is an herbaceous plant that bears palmately lobed or heart-shaped leaves. The flowers of sweet potato plant are sympetalous (fused petals) and medium-sized. Sweet potato is an elongated, tuberous root that is tapered at the end. The skin of this root vegetable is smooth. Not all varieties of sweet potatoes are equally sweet. Compared to the sweet potatoes having orange, red or pink flesh, those with white or light yellow flesh are less sweet.
Therefore, while selecting sweet potatoes at stores and supermarkets, you should opt for sweet potatoes whose size varies from small to medium. In addition, ensure that their skin is not blemished. Such sweet potatoes will become softer after cooking. You should store sweet potatoes in a cool place that is beyond the reach of light. It is important to use the sweet potatoes within a week of purchasing them.
Compared to the common potatoes, sweet potatoes offer us several health benefits. Sweet potatoes are loaded with vitamins A and C, which are invaluable for our health, as they are effective in preventing several cancer risks. Findings of several researches have shown that sweet potatoes contain abundance amounts of antioxidant pigments called anthocyanins. This antioxidant is contained in the starch of this root vegetable. As most of us are aware, antioxidants are effective in neutralizing the damages caused by free radicals and heavy metals.
Moreover, the storage enzymes present in sweet potatoes also possess antioxidant properties. When the sweet potato is damaged it releases a substance called sporamin that facilitates healing itself.
Aside from the antioxidants, sweet potatoes also possess anti-inflammatory properties, mainly owing to the presence of beta-carotene, vitamin C, vitamin B6 and the essential mineral manganese. All these nutrients are highly effective in curing external as well as internal inflammations. It has been found that consumption of sweet potatoes results in a decrease of inflammation in the brain tissue as well as the nerve tissues all over the body.
Sweet potatoes also contain elevated levels of beta-cryptoxanthin, which is proven to be helpful in preventing chronic inflammatory diseases like rheumatoid arthritis. Findings of different studies have shown that people consuming beta-cryptoxanthin foods face 50 percent less chances of developing inflammatory arthritis compared to people who eat very less amount of these foods. Consuming only one serving of foods rich in beta-cryptoxanthin content like sweet potatoes provides significant benefits.
Moreover, sweet potatoes contain vitamin C, which is helpful in sustaining collagen in our body and also lessening the chances of developing specific types of arthritis.
Carotenoids present in sweet potato may prove to be useful for our body to response to insulin and, at the same time, keep the blood sugar levels stable. In addition, this root vegetable also encloses a considerable quantity of vitamin B6, which helps in preventing diabetic heart disease. Sweet potatoes also contain high amounts of soluble dietary fiber which is useful in lowering the cholesterol as well as blood sugar levels. In addition, they contain plenty of chlorogenic acid that may lower the body's resistance to insulin.
Another important aspect of sweet potato is that this vegetable soothes the stomach. It contains beta-carotene, vitamin C and B vitamins in addition to calcium, which are all useful in curing stomach ulcers. The dietary fiber present in sweet potatoes helps in preventing constipation as well as acidity, thereby lessening the risks of developing stomach ulcers. At the same time, the vegetable's anti-inflammatory attributes also help to alleviate pain as well as inflammation of ulcers.
Although it may seem to be incredible to many, sweet potatoes supply our body with over 90 percent of its requirement for vitamin A. Scientists have discovered that people who smoke regularly ought to consume more foods containing rich amounts of vitamin A. This is mainly because a deficiency of vitamin A may be responsible for conditions like emphysema as well as various diseases related to the lungs, especially in people who are smokers.
As mentioned earlier, sweet potatoes are an excellent resource of dietary fiber, which helps to encourage a robust digestive system. Studies have found that dietary fiber may also be useful for cleansing heavy metals like mercury and arsenic from our digestive tract.
Most people are aware of the fact that vitamin C is vital for keeping cold and flu viruses at bay. However, very few people know that this essential vitamin also has a vital role in digestion, formation of tooth and bone, and blood cell formation. In addition, vitamin C speeds up healing process curing wounds earlier than usual, and helps in collagen production, thereby maintaining the youthfulness and elasticity of the skin. At the same time, this vitamin is necessary to help us deal with stress. Apparently, vitamin C also works to protect our body from various toxic substances that may be related to cancer.
Sweet potatoes also contain potassium, which is considered to be among the most important electrolytes that aid in controlling our heartbeat as well as nerve signals. Similar to all other electrolytes, potassium also plays various roles and some of these include lessening swelling, unwinding muscle contractions and protecting as well as regulating the functioning of the kidneys.
The flesh of some sweet potatoes is vibrant orange and this is an indication that these vegetables contain elevated amounts of carotenoids such as beta carotene as well as other carotenoids. Basically, in our body, these carotenoids are the precursors to vitamin A. It is worth mentioning here that carotenoids are useful in reinforcing our eyesight and also enhance the immune system, thereby protecting us from various diseases. At the same time, they are potent antioxidants that help to provide protection against cancer and also shield us from the unpleasant effects of aging.
From the nutritional point of view, sweet potatoes have much to offer. They are generally packed with beta carotene and vitamin A, in addition to other vitamins like vitamin C, vitamin E and vitamin B6. This root vegetable also contains sufficient amounts of the essential mineral potassium. Sweet potatoes are also an excellent source for dietary fiber plus complex carbohydrates. Similar to several other vegetables, sweet potatoes also do not contain any fat or cholesterol. A sweet potato of medium size supplies us with roughly 100 calories.
Sweet potatoes assume a variety of roles in our kitchen. Sometimes they are used as appetizers, added to soups, made into side dishes as well as desserts with the same flamboyance. You can also bake the unpeeled sweet potatoes, season them with herbs and olive oil or grill them for some minutes per side. Some people even consume the leaves of sweet potatoes in the way they eat spinach.