Fat- and cholesterol-free, sweet potatoes are high in vitamins B6, C and D, and contain sufficient sources of iron, magnesium and potassium. Like carrots, they are also high in beta-carotene, the precursor for processing vitamin A within your body.
Unlike regular potatoes, referred to as tubers, or underground stems, sweet potatoes are roots and are believed to also carry nutrients in their leaves. "Although studies have confirmed that water-soluble vitamins exist in sweet potato roots and leaves, there has been limited information about how these vitamins are actually distributed in the plants," reports ReadyNutrition.com.
Delicious and affordable, sweet potatoes provide a multitude of health benefits
Exploring this concept, researchers Wilmer Barrera and David Picha from Louisiana State University (LSU) Agricultural Center published a research study in the journal HortScience, showing that both the mature and young leaves of sweet potatoes provide significant health benefits, including vitamin B6.
The study's objective specifically focused on determining the content of ascorbic acid, thiamin, riboflavin and vitamin B6 in a variety of sweet potatoes, including the Beauregard Sweet Potato, a current industry standard that was developed at LSU in 1987.
Not only is the Beauregard Sweet Potato highly regarded by Louisianans, but it's also the world's most popular sweet potato
For their experiment, scientists also used the "LA 07-146" sweet potato, the second most popular (behind Beauregard) variety in Louisiana, differing by its red skin and "good sugar" content.
"It's a very good french fry sweet potato," said LSU AgCenter sweet potato breeder Don Labonte.
In a sweet potato lot at LSU, scientists analyzed the plant's essential vitamin content in a range of foliar tissues including buds, vines, young petioles, young leaves, mature petioles and mature leaves as well as root tissues including the skin, cortex and pith tissue at the proximal, distal and center regions of the root.
The fields were planted in late October and again the following September, with a third experiment being conducted in order to study water-soluble vitamin content among different sweet potato root tissues.
Study shows sweet potato leaves contain significant amounts of vitamin content
Their results found that ascorbic acid (AA) content differed among varying tissue types, with young leaves containing the highest amount, followed by mature leaves and buds. The AA content was the lowest in mature petioles, according to researchers.
Buds also contained high amounts of AA, higher than the sweet potato's roots, vines and petiole tissues. "No thiamin was detected in foliar tissue, whereas mature leaves contained the highest riboflavin and vitamin B6 content (0.22 to 0.43 mg and 0.52 to 0.58 mg, respectively)," the scientists noted.
"In root tissues of 'Beauregard' and 'LA 07-146' sweetpotatoes, [sic] the AA content was lower in the skin (1.9 to 5.6 mg and 2.54 to 3.82 mg, respectively)."
"The AA content in the cortex and pith tissue at the proximal, distal, and center of the root was generally similar," scientists said, while thiamin content varied among root tissues, with the skin containing the highest riboflavin content and the lowest vitamin B6 content across root tissues of both strains.
The study's results confirm earlier reports suggesting that sweet potato leaves can be a great source of multiple water-soluble vitamins in the human diet, making them an attractive choice for your next dish.