The sweet potato is a dicotyledonous plant that belongs to the family Convolvulaceae. Its large, starchy, sweet-tasting, tuberous roots are a root vegetable. The young leaves and shoots are sometimes eaten as greens. Of the approximately 50 genera and more than 1,000 species of Convolvulaceae, I. batatas is the only crop plant of major importance some others are used locally, but many are actually poisonous. The sweet potato is only distantly related to the potato (Solanum tuberosum) and does not belong to the nightshade family.
The genus Ipomoea that contains the sweet potato also includes several garden flowers called morning glories, though that term is not usually extended to Ipomoea batatas. Some cultivars of Ipomoea batatas are grown as ornamental plants; the name "tuberous morning glory" may be used in a horticultural context.The plant is a herbaceous perennial vine, bearing alternate heart-shaped or palmately lobed leaves and medium-sized sympetalous flowers. The edible tuberous root is long and tapered, with a smooth skin whose color ranges between yellow, orange, red, brown, purple, and beige. Its flesh ranges from beige through white, red, pink, violet, yellow, orange, and purple. Sweet potato varieties with white or pale yellow flesh are less sweet and moist than those with red, pink or orange flesh.
In certain parts of the world, sweet potatoes are locally known by other names. In New Zealand English, the Maori term kumara is commonly used. Although the soft, orange sweet potato is often called a "yam" in parts of North America, the sweet potato is botanically very distinct from a genuine yam, which is native to Africa and Asia and belongs to the monocot family Dioscoreaceae. To add to the confusion, a different crop plant, the oca, Oxalis tuberosa, is called a "yam" in many parts of Polynesia, including New Zealand. To prevent confusion, the United States Department of Agriculture requires sweet potatoes labeled as "yams" to also be labeled as "sweet potatoes". The sweet potato is North Carolina's state vegetable.
The plant does not tolerate frost. It grows best at an average temperature of 24 °C, abundant sunshine and warm nights. Annual rainfalls of 750–1,000 mm are considered most suitable, with a minimum of 500 mm in the growing season. The crop is sensitive to drought at the tuber initiation stage 50–60 days after planting, and it is not tolerant to water-logging, as it may cause tuber rots and reduce growth of storage roots if aeration is poor. Depending on the cultivar and conditions, tuberous roots mature in two to nine months.
They are high in vitamin B6. Vitamin B6 helps reduce the chemical homocysteine in our bodies. Homocysteine has been linked with degenerative diseases, including the prevention of heart attacks.
They are a good source of vitamin C. While most people know that vitamin C is important to help ward off cold and flu viruses, few people are aware that this crucial vitamin plays an important role in bone and tooth formation, digestion, and blood cell formation. It helps accelerate wound healing, produces collagen which helps maintain skin’s youthful elasticity, and is essential to helping us cope with stress. It even appears to help protect our body against toxins that may be linked to cancer.
They contain Vitamin D which is critical for immune system and overall health at this time of year. Both a vitamin and a hormone, vitamin D is primarily made in our bodies as a result of getting adequate sunlight. You may have heard about seasonal affective disorder (or SAD, as it is also called), which is linked to inadequate sunlight and therefore a vitamin D deficiency. Vitamin D plays an important role in our energy levels, moods, and helps to build healthy bones, heart, nerves, skin, and teeth, and it supports the thyroid gland.
Sweet potatoes contain iron. Most people are aware that we need the mineral iron to have adequate energy, but iron plays other important roles in our body, including red and white blood cell production, resistance to stress, proper immune functioning, and the metabolizing of protein, among other things.
Sweet potatoes are a good source of magnesium, which is the relaxation and anti-stress mineral. Magnesium is necessary for healthy artery, blood, bone, heart, muscle, and nerve function, yet experts estimate that approximately 80 percent of the population in North America may be deficient in this important mineral.
They are a source of potassium, one of the important electrolytes that help regulate heartbeat and nerve signals. Like the other electrolytes, potassium performs many essential functions, some of which include relaxing muscle contractions, reducing swelling, and protecting and controlling the activity of the kidneys.
Sweet potatoes are naturally sweet-tasting but their natural sugars are slowly released into the bloodstream, helping to ensure a balanced and regular source of energy, without the blood sugar spikes linked to fatigue and weight gain.
Their rich orange colour indicates that they are high in carotenoids like beta carotene and other carotenoids, which is the precursor to vitamin A in your body. Carotenoids help strengthen our eyesight and boost our immunity to disease, they are powerful antioxidants that help ward off cancer and protect against the effects of aging.
Studies at Harvard University of more than 124,000 people showed a 32 percent reduction in risk of lung cancer in people who consumed a variety of carotenoid-rich foods as part of their regular diet. Another study of women who had completed treatment for early stage breast cancer conducted by researchers at Women’s Healthy Eating and Living (WHEL) found that women with the highest blood concentrations of carotenoids had the least likelihood of cancer recurrence.
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