Sweet! Potatoes!
Real Foods that Heal
volume 2, #12
July 29, 2008
Sweet Potatoes
The way you think of sweet potatoes probably depends to a large extent on where you spent your younger years. Or more precisely, how did the people who did your cooking traditionally deal with this humble root? I recall sweet potatoes whole, baked in skin in the oven, then seemingly turned into a dessert instead of a vegetable on my plate under tablespoons of butter and brown sugar. That very pleasant memory is linked to childhood dinners on crisp fall nights or to Thanksgiving. But I also recall the boiled yams which would occasionally make an appearance in our school cafeterias. If I had known then what I know now, I would have eaten the yams (a mind over matter exercise in 5th grade) and left the pudding on the tray.
That beautiful orange color of the sweet potato is a giveaway as to why it is such a healthy food star. It is a very rich source of beta carotene and other natural carotenoids, precursors of vitamin A which are powerful antioxidants. A mere 100 grams (1/2 cup) of baked sweet potato supplies almost 20,000 units of vitamin A precursors! (You certainly would not need to take a vitamin A supplement on a sweet potato day). Recall that an important role of antioxidants is to neutralize free radicals (sometimes called reactive oxygen species) in the body. These free radicals are a natural byproduct of the energy-producing chemistry of all of our cells, which is why the sole process of being alive and breathing air creates a requirement for antioxidants to protect our cells against oxidative damage to cells and DNA. Because damaged DNA programs cells to malfunction, research has linked this oxidative damage to DNA as one of the initiating factors for cancer. The clear flip-side of this situation is that human diets which are high in vegetables and fruits are associated with lower rates of cancer, probably largely in part to the presence of these carotenoids and other antioxidants. Specifically, studies on dietary reduction of breast cancer risk give special importance to the role of carotenoids. Interestingly, lower heart disease rates are also associated with diets higher in plant based antioxidants.
Sweet potatoes have a very different profile, in botanical history and in nutrition, than the more plentiful white potatoes which fill American plates. Sweet potatoes are native to the Americas and were cultivated as a staple food crop long before the arrival of Europeans. There is some confusion between yams and sweet potatoes, but according to sources, the “yams” commonly in American markets are actually orange-fleshed sweet potatoes, not the starchy yams of Caribbean islands. White potatoes also originated in the Americas (high elevations of the Andes), were taken to Europe where they became a staple food, and have in recent years become one of the most consumed foods in the world. The white potato however lacks the nutritional value of its more colorful cousin. White potatoes are somewhat pro-inflammatory, tend to raise blood sugar, and provide minimal levels of any important nutrients. The sweet potato on the other hand, has a very low glycemic load (does not significantly raise blood sugar), and is anti-inflammatory.
Considering the combination of antioxidants, anti-inflammatory properties, and low glycemic index, the sweet potato can be considered an important ally in the prevention of cancer, heart disease, and the degenerative inflammatory diseases of aging. So what are you waiting for? Put one in the oven and enjoy!
Sweet Potato Soup
Peel and cube two large sweet potatoes, and boil or steam until tender. Take 2 cups of the cooked sweet potato and combine in a blender with 2 cups of vegetable broth and 1 cup of low fat milk (rice or soy milk can be substituted). Add ½ tsp salt, 1 tsp grated fresh ginger root, 1/8 tsp cinnamon and 1/8 tsp nutmeg. Add a small bit of sweetener if you feel necessary, such as up to 1 tbsp of brown sugar. Blend thoroughly; then return to a saucepan to heat for serving.
To your health,
Robert Pendergrast, MD
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