Sarah's Superfoods: Sweet potatoes

Posted in March, April, May, All Recipes, Spring, on

Country Living magazine May 2015

This article first appeared in Country Living in May 2015. To read the PDF copy of the feature as it appeared in the magazine, please click here, or you can read the article in full below.

As a nation, we’re devoted to potatoes, eaten every which way. But why not use more of the healthy, coral-orange sweet potato? I make a dish similar to dauphinoise potatoes, with sweet potato, coconut, ginger and lime, which has the same comforting texture, yet a much greater nutritional value. The same is true of soup: swap cream-laden vichyssoise for my super-healthy, saffron-coloured sweet potato, carrot and peanut butter recipe. It’s one of my favourites.

The sweet potato is a great source of fibre and vitamins, particularly C and B6. Also, like carrots, the orange fleshed varieties are packed with an orange pigment called beta-carotene (in the family of carotenoids). The deeper the orange, the greater the density of the pigments; sweet potatoes have the highest level, followed by carrots, and other orange and yellow fruit and vegetables, such as squash, melon, peppers and apricots. Surprisingly, the dark, leafy greens kale and spinach also have high concentrations.

Beta-carotene aids night-time vision, is anti-inflammatory and appears to help the immune system. However, most importantly, diets rich in carotenoid-dense foods (beta-carotene included) can help to prevent cancer. A large study at Harvard University showed a 32 percent reduction in the risk of lung cancer in those who consumed more carotenoid-rich foods as part of their regular diet, compared with those who ate less. Another study of women (conducted by Women’s Healthy Eating and Living), who had completed treatment for early-stage breast cancer, found that those with the highest blood concentrations of carotenoids (from a diet generally high in these fruit and vegetables) had the least likelihood of cancer recurrence.

Sweet potato is a carbohydrate-rich food that releases its natural sugars slowly into the bloodstream (particularly helpful to anyone with type 2 diabetes), whereas a white bread sandwich or standard baked potato causes a rapid sugar spike in our blood (owing to their high glycaemic index, or GI). When boiled or steamed, sweet potatoes have a reasonably low GI of 46, compared to 82 if they are roasted and 94 if they’re baked. White bread has a GI of 70; normal jacket potatoes of 69 with skin, or 98 with no skin, so steamed sweet potatoes are slow in their sugar release by comparison. Incidentally, carotenoids are a fat-soluble vitamin, so always eat them with a little fat, such as olive oil or coconut milk, or combine them with nuts to aid absorption. If you buy organic varieties, you can eat the flesh and skin; otherwise peel before eating, as the skin may have been treated with dye or wax. Then

drop them into a bowl of water to prevent the flesh oxidising in the air.

Native to Central and South America, sweet potatoes aren’t frost-hardy and need a long growing season with plenty of light, so they are probably a vegetable to buy rather than grow. It’s now, in mid spring, when fresh, local, seasonal vegetables are hard to find, that they should rise to the top of the shopping list.

This article also includes four sweet potato recipes:

  • Sweet potatoes with coconut, ginger and lime
  • Sweet potato, carrot and peanut butter soup
  • Sweet potato tagliata with watercress, ginger and soy
  • Adzuki bean and root vegetable chilli