As a holiday table staple, the humble sweet potato is often taken for granted. Yet, this versatile root vegetable is not only a culinary chameleon but also one of humanity's oldest cultivated foods, boasting an impressive array of health credentials that make it a worthy addition to any diet year-round.
A Storied History and Nutritional Powerhouse
Archaeological evidence reveals that sweet potatoes were first domesticated in South America over 4,500 years ago, according to seed historian and journalist Michelle Johnson. This resilient and adaptable plant, with thousands of known cultivars, is a member of the morning glory family and is entirely edible. Despite common misconceptions, it is botanically unrelated to the standard white potato or yam.
From a nutritional standpoint, a single medium-sized orange sweet potato (approximately 140g cooked) provides around 130 calories, 30g of carbohydrates, and 2g of protein. The majority of its carbs come from complex, slow-digesting starches, with less than half derived from its natural sugars. Its preparation method significantly impacts its effect on the body; steaming or boiling helps retain resistant starch for a lower glycemic index, while high-temperature roasting can increase sugar content.
Blood Sugar Management and Digestive Health
Despite their sweetness, sweet potatoes are an excellent carbohydrate choice, even for individuals managing diabetes. New York-based dietitian Asako Miyashita highlights their high fibre content—4-6g per serving—as a key factor. This fibre helps stabilise blood sugar levels, lower cholesterol, and promote feelings of fullness.
Miyashita recommends consuming them with the skin on for maximum fibre benefit and pairing a half-cup serving with green vegetables and protein for optimal blood sugar balance. An interesting tip is that cooking and then cooling sweet potatoes before eating increases their resistant starch content, which acts like additional fibre to prevent blood sugar spikes.
Beyond fibre, sweet potatoes offer a unique digestive aid. The white sap visible in a raw tuber contains a compound called yarapin, which supports peristalsis—the muscular contractions that move food through the digestive tract.
Micronutrient Riches and The Colour Spectrum
Sweet potatoes stand out from other staple starches due to their dense micronutrient profile. One medium potato provides significant amounts of manganese, iron, vitamins C and B6, and calcium. It also delivers 12% of your daily potassium and 34% of your daily copper. Chef and dietitian Sharniquia White notes that copper is vital for skin health, protects against oxidative stress, and supports brain and nervous system function, with a 2025 observational study linking higher copper intake to better cognitive test performance.
The colour of the sweet potato flesh signals different antioxidant profiles. Orange varieties like Jewel or Beauregard are rich in beta-carotene, which the body converts to vitamin A, crucial for vision, immune function, and skin health. Pairing them with a healthy fat like olive oil enhances absorption.
Purple sweet potatoes, such as the Japanese Okinawa, are packed with anthocyanins. Laboratory tests show these antioxidants are exceptionally potent at fighting cell-damaging free radicals, even outperforming those in red cabbage and grapes, and research suggests promising antitumor properties.
While white-fleshed varieties like Hannah may have fewer antioxidants, they still offer more micronutrients and fibre than standard white potatoes. The consensus from experts is not to replace one with the other entirely, but to enjoy both as part of a varied diet.
Selecting, Storing, and Endless Culinary Possibilities
When shopping, choose firm sweet potatoes with smooth, unblemished skin and no odour—a sweet smell can indicate spoilage. Store them in a cool, dry place. Their culinary versatility is vast. White suggests innovative uses like blending cooked sweet potato into smoothies, grilling thick slices like a steak, or using roasted rounds as a base for avocado 'toast'. A recent social media trend even saw them baked whole and stuffed with cheese.
"You can have them savoury, you can have them sweet, you can have them for a snack, you can have them for an entrée," says White. "Not only are they nutritious—they're also very versatile." This ancient superfood, it seems, is perfectly suited for modern, health-conscious kitchens.
