What is it?
A starchy, sweet-tasting root vegetable – which contrary to popular belief, is actually unrelated to its well-known rival, white potato. The bright orange variety is the best known type of sweet potato in the UK, but white, yellow, red and purple-fleshed varieties also exist.
- They are lower carb than white potatoes
- They are a great source of vitamin A, iron and other key vitamins and minerals
- Eating sweet potatoes can help fight the signs of skin ageing
- They can boost the immune system
The scientific facts
- Sweet potatoes are a waist-friendly alternative to white potatoes, but that’s not due to a difference in carb content. Both types of potato have similar amounts of carbohydrates and sweet potatoes actually have five-times more sugar than white potatoes (which is why they taste sweeter). Health claims that sweet potatoes are lower carb than white potatoes are based on their lower glycaemic index (as this study suggests). The carbs in sweet potatoes are more slowly broken down to sugar in the body than white potatoes, which means that the so-called superfood doesn’t raise blood sugar as high as ordinary potatoes.
- Brightly-coloured sweet potato varieties are indeed a great source of beta carotene (the precursor to vitamin A), vitamin B6, magnesium and potassium. And beta carotene has an important role in keeping your eyes working properly and supporting the immune system. As such, health claims that sweet potato can help ward off a cold are not as far-fetched as they may seem.
- Studies, like this have shown that purple-fleshed varieties of sweet potato are high in health-boosting antioxidants, called anthocyanins, which, like the carotenoids found in the orange varieties of the sweet spud, help to protect against the effects of ageing and can lower the risk of developing certain types of cancers.
Nutritional facts – Sweet potato versus white potato
Many popular clean-eating and sugar-free diet plans recommend swapping white potatoes for sweet potatoes. But is there really that much difference? Here’s how 100g of baked (orange-fleshed) sweet and white potato compare:
- Kcals: Sweet potato 90 v white potato 93
- Protein: Sweet potato 2g v white potato 2.5g
- Carbohydrates: Sweet potato 21g v white potato 21g
- Sugar: Sweet potato 6g v white potato 1.2g
- Fibre: Sweet potato 3.3g v white potato 2.2g
- Fat: Sweet potato 0.2g v white potato 0.1g
- Vitamins, minerals and miscellaneous nutrients: Sweet potato has much more beta carotene (vitamin A) and twice as much calcium and vitamin C than white potato, but that’s its only edge. It’s higher in blood-pressure-raising sodium and lower in potassium, iron and magnesium.
Winner: Sweet potato – but only because its high antioxidant levels make the root vegetable superior at protecting against disease. However, as both have almost the same nutritional make-up, it’s a tie if both spuds are judged for their weight loss potential and general nutritional benefits.
Worth the hype?
Sort of. If you have to eat potatoes then sweet potatoes are the better alternative. However there are better (less calorific) food sources of the antioxidants that sweet potatoes provide – like carrots, bell peppers and berries.