One of the oldest staples of the human diet, relics of sweet potatoes have been found in Peruvian caves dating back 10,000 years. They are native to Central America. In the late 15th century, Christopher Columbus and Spanish explorers introduced the sweet potato to the Southern United States and to Europe. Spanish and Portuguese explorers spread cultivation of the sweet potato to countries including the Philippines, Africa, India, and Southern Asia. Records indicate that the sweet potato may have spread from Central America to Polynesia before the arrival of European explorers.
Sweet potatoes are often confused with yams, but these two tubers are from unrelated families. The sweet potato is from the Morning Glory family or Convolvulaceae, and the species I. batata. There are nearly 400 varieties with flesh colors ranging from deep orange to purple to white. Most products called “yams” in the United States are actually orange-fleshed sweet potatoes.
Though not native to China, sweet potatoes are considered similar to yams in Chinese medicine. They nourish the spleen and pancreas, and the kidney yin energy, which in turn promotes healthy consistency of the protective fluids that coat the mucous membranes throughout the body. They also promote healthy elasticity of blood vessels, cartilage, and connective tissues. Traditionally, sweet potatoes have been used to increase milk production in new mothers, to remove toxins from the digestive tract, and to treat general weakness and thinness. Caution is given that over-consumption of sweet foods like sweet potatoes can weaken the digestive system.
Sweet potatoes are a good source of both soluble and insoluble fibers, both of which are needed to maintain healthy blood lipid levels. The orange varieties are exceptionally high in carotenoids, the compounds that make vitamin A in the body. Historically, they have been used around the world to improve vision. They have high antioxidant and anti-inflammatory values, making them a good addition to a heart healthy diet. Sweet potatoes naturally stimulate the release of serotonin in the body, which can improve conditions that lead to depression. They are also studied for their anti-bacterial and anti-fungal activity, as well as their role in an anti-cancer diet. The pigments found in sweet potatoes may reduce heavy metal toxicity and reduce damage from free radicals. Eat sweet potatoes lightly steamed with a small amount of healthy oil for optimal nutrient absorption.
Locally grown, low-calorie, nutrient-dense, full-flavored sweet potatoes are available now at our awesome winter Santa Fe Farmers Market!
Mary Sjoberg, R.Ph. (references available upon request)
