Its sweet potato season again here in Hainan and you’ll no doubt be seeing the qiaotou sweet potato everywhere for the next few months, from supermarkets to street markets to vendors roasting and selling them on the streets.
This delicious little spud is something of a super food, if you’re already a fan you’ll need no convincing, if you’re not, here’s why perhaps you should be.
Sweet potatoes are large starchy, root tubers and are only distantly related to the potatoes we use to make chips (or French fries depending on which part of the world you’re from). Tubers store water and energy like starch and carbohydrates under the soil which is then used to feed the plant above.
There are a staggering 6,500 different varieties of sweet potato worldwide, the predominant variety grown in Hainan is called qiaotou.
A recent study on diet and longevity of centurions on the Japanese island of Okinawa, where islanders have some of the highest life expectancies in the world, revealed that, on average, 60% of their calories came from the humble sweet potato. They eat very little in the way of meat, dairy, or processed foods preferring a plant based diet.
They eat lots, and lots, and lots of sweet potatoes.
Traditional Papua New Guinea Highlanders also eat a lot of sweet potatoes. It has been estimated that tubers like sweet potatoes and yams provide a staggering 90% of their calorie intake.
A study published in the Journal of Internal Medicine in 1994 found that, when native groups such as these remain faithful to their traditional way of eating, they had lower blood pressure and weight when compared to their western counterparts and very rarely experienced heart disease, strokes, or other modern chronic diseases such as cancers of the colon, breast or prostate.
Sweet potatoes are high in fiber, vitamin C, potassium, pantothenic acid (vitamin B5), niacin (vitamin B3), vitamin B6, manganese, magnesium, and copper.
A single sweet potato provides more than double the daily requirements of vitamin A. Vitamin A is an important antioxidant that researchers believe promotes good eyesight, resistance to the effects of aging, and cancer prevention.
And get this, one large sweet potato contains 68 mg of calcium (daily recommended requirement is 500-700 mg) which is a major mineral indispensable in healthy bone development in childhood and youth and adequate intake prevents bone loss in later life. Blood calcium is also responsible for proper nerve function, contraction of muscles and blood clotting.
Other health benefits of sweet potatoes
1 They are an excellent source of fiber, especially the skin, they are great for digestive health.
2 They have been found to lower LDL (bad) cholesterol, they keep your heart healthy.
3 The fiber and complex carbohydrates in sweet potatoes can help keep your blood sugar stable,
4 Sweet potatoes are rich in antioxidants that prevent free radical damage in your body. The vitamin A helps your body make immune cells which boosts your immunity.
5 Sweet potatoes contain alpha-carotene, beta-carotene, lutein, and zeaxanthin which are important for good eye health.
6 Up to 80% of the protein in sweet potatoes is a type of storage protein known as sporamin. This unique protein has been studied for anti-cancer ability and found to be effective in several disease types
7 Eating sweet potatoes may also help reduce inflammation. This is chiefly due to their high levels of beta-carotene, vitamin C, and magnesium.
And now for a bonus sweet potato recipe
For the mash
1kg sweet potatoes, peeled and cut into large chunks
2 tbsp milk
50g mature cheddar, finely grated
For the mince
1 tbsp cooking oil
2 onions, halved and sliced
500g lean beef mince (5% fat)
1 tbsp smoked paprika,
1 tbsp ground cumin
1 tbsp ground coriander
1 tbsp mild chilli powder
RT Mart and Carrefour usually have a decent selection of spices, can be substituted for your own taste.
400g black-eyed beans
400g chopped tomatoes
1 large green pepper, diced
326g of sweetcorn, broccoli or salad (optional)
Boil the sweet potato for 15 mins or until tender, taking care not to overcook.
Meanwhile, heat the oil in a large, deep, non-stick frying pan. Add the onions, cover and cook for 8 mins or until softened and starting to colour. Stir in the mince, breaking it up with a wooden spoon until browned. Stir in all the spices, then add the beans with water, the tomatoes and pepper. Cover and simmer for 20 mins. Boil the corn, season and take off the heat.
While the mince cooks, mash the potatoes with the milk to make a stiff mash. Spoon the mince into six individual pie dishes, top each with some mash, then sprinkle over the cheese and a little paprika.
The pies can now be frozen. If eating straight away, put under a hot grill until piping hot and the cheese is melted. To cook from frozen, thaw completely, then reheat in the oven on a baking tray at 180C/160C fan/ gas 4 for 30-40 mins or until piping hot throughout. Serve with broccoli or a salad, if you like, which will take you to all 5 of your 5-a-day.