Do you have sweet potatoes as part of your holiday meals?
While most people know that sweet potatoes are part of our traditional Thanksgiving and Christmas meals, most people are not aware of how exceptionally nutritious these vegetables are. Additionally, the health benefits contained in these root vegetables are nothing short of astounding.
Sweet potatoes are in season locally in November and December; 2nd Street Market vendors currently have local sweet potatoes, and Liberty Market has organic non-GMO sweet potatoes.
I yam what I yam
The orange-colored root vegetable that we think of as a “yam” in the United States is really a sweet potato. Up until the mid-20th century, the sweet potatoes in this country had white-flesh; when the current orange variety was introduced, it was given the name “yam” to distinguish it from the OTHER variety of sweet potato. It is not a true yam.
The orange-flesh sweet potatoes are extremely rich in beta-carotene; the purple-fleshed varieties are exceptional sources of anthocyanins (anti-oxidizing and anti-inflammatory plant pigments). All sweet potatoes are rich in unique phytonutrients, such as polysaccharide-related molecules known as batatins and batatosides. Sweet potatoes also have storage proteins called sporamins which have unique antioxidant properties. Sweet potatoes are an excellent source of vitamins A, C and manganese, and a good source of copper, dietary fiber, vitamin B6, potassium and iron.
Let’s start with those anthocyanins
Sweet potatoes are not always orange-fleshed on the inside; the inside flesh can also be anywhere from somewhat purple to spectacularly purple in color. Particularly in the purple-fleshed sweet potato, anthocyanins have important antioxidant and anti-inflammatory properties. As these plant pigments pass through the digestive tract, they lower the health risks from heavy metal residues (such as arsenic, cadmium and mercury) and oxygen radicals. This risk reduction is important for all individuals, but even more so for those with digestive tract problems like irritable bowel syndrome or ulcerative colitis.
Cooking methods focusing on anthocyanins
For maximum preservation of sweet potato anthocyanins, steaming is the preferred method. Two minutes of steaming have been shown to deactivate certain enzymes that might otherwise be able to break down the anthocyanins. With these enzymes deactivated by steaming, the natural anthocyanin extracts (and their anti-inflammatory and antioxidant properties) become extremely stable.
Next: Sweet potatoes and vitamin A
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