We know sweet potatoes are a great source of vitamin A, but what’s the best way to access it?
Reviewed by Dietitian Casey Wing, RD, CD
Key Points
- Boiling or steaming sweet potatoes with the skin on preserves the most beta-carotene and antioxidants.
- Pair sweet potatoes with healthy fats like olive oil or avocado to maximize vitamin A absorption.
- Cooking methods like roasting or air-frying lose more nutrients but can still be nutritious with added fat.
There aren’t many veggies that taste like dessert, make any side dish sing and help you check a big orange box on the rainbow quite like the sweet potato. Its vibrant orange color comes from beta-carotene, the plant pigment your body converts into vitamin A, which is essential for healthy vision, immune function and skin integrity. One medium sweet potato delivers enough beta-carotene to meet your total daily vitamin A requirement. Beta-carotene, however, is fat-soluble, which means your body needs dietary fat present to absorb it properly. So, while eating sweet potatoes is valuable, how you eat them could make them even more of an asset to your diet.
When it comes to preparation, dietitians recommend boiling or steaming sweet potatoes, along with adding some fat, for maximum vitamin A absorption. Here’s why.
Why Boiling/Steaming Sweet Potatoes with Fat Supports Vitamin A Absorption
Cooking Unlocks Nutrients
Raw sweet potatoes deliver less beta-carotene to your body than cooked, even though they technically contain more of it. That seems counterintuitive, until you understand that the beta-carotene is locked inside tough plant cell walls. Heat processing breaks those walls down, releasing the pigment so your digestive system can actually access it. Cooking isn’t destroying nutrients here; it’s unlocking them.
High Heat Can Damage Nutrients
Compared to boiling or steaming, baking takes a far greater toll on vitamin A levels. “Research suggests that steaming and boiling preserve more beta-carotene in sweet potatoes than baking, with steaming having a slight advantage to boiling,” says Dawn Jackson Blatner, RDN, CSSD. Indeed, studies show that both boiling and steaming preserve more than 80% of the original beta-carotene content, significantly more than baking or frying. Moreover, Blatner tells us, “Another nutrition advantage of steaming is fewer water-soluble vitamins, like vitamin C and B6, are lost in the cooking process, because they aren’t submerged in water while cooking.” “If you’re going to boil sweet potatoes, try to do it in recipes where you will use the water, like soups or stews.”
Abbie Gellman, M.S., RD, CDN, agrees that this is a smart approach: “To use boiling as the method of choice, I would recommend using the vegetables in dishes like soups and stews. That way, you’re cooking them and using the water or stock that is boiling and simmering them, therefore, any vitamins that may leach out will still be eaten.”
It Helps Preserve Nutrients in the Skin
Research shows that the sweet potato skin is significantly richer in antioxidants, like beta-carotene, than the flesh. Baking reduces antioxidants in the skin; boiling and steaming are far gentler. Keeping the skin on during cooking, then eating it, gives you a meaningful nutritional bonus that you might otherwise toss in the compost bin.
Gellman recommends keeping the skin on for most fruits and vegetables whenever possible. “Some foods that have a lot of beta-carotene, such as winter squash, may have mixed reviews for leaving the skin on, while others, like carrots, are easy to wash thoroughly and use without peeling,” she says. The sweet potato falls firmly in the keep-it-on camp.
Fat Boosts Absorption in the Body
Beta-carotene is fat-soluble, which means it requires dietary fat to be absorbed and transported through your body. Research consistently shows that eating beta-carotene-rich foods containing just 3 to 5 grams of fat (about the amount in 1 teaspoon of olive oil) can increase absorption of that nutrient. Katie Morford, M.S., RDsuggests, “It’s a matter of stocking the fridge and pantry with easy-to-grab options to work into your repertoire.” Morford always stocks up on avocados, full-fat Greek yogurt, nut and seed butters, chili crisp and a vinaigrette of some kind. “These are all very versatile ways to enrich a sweet potato with some flavorful fat,” she says, to help turn a nutritious dish into a genuinely strategic one.
Gellman keeps it equally practical: “Including some fat with sweet potatoes can be as simple as topping a [cooked] sweet potato with full-fat yogurt, sour cream, cheese, toasted nuts or seeds, avocado or a pesto made with oil, nuts and cheese. If you’re cutting up sweet potatoes to roast bite-sized, your oil should do the trick.”
Other Nutritious Ways to Enjoy Sweet Potatoes
Boiling and steaming are the winners for vitamin A absorption, but the best sweet potato is ultimately the one you’ll want to eat. Here are other preparations to keep in your rotation.
- Roasted or baked: Higher heat means more beta-carotene loss, but roasted sweet potatoes with a generous coat of olive oil still deliver a solid nutritional punch, and the fat helps offset some of the absorption gap. Leave the skin on for maximum nutrient preservation.
- Microwaved: This method is surprisingly gentle on nutrients, especially the antioxidants in the skin. It’s also a quick option when you’re short on time. Remember to pair with a fat source, like avocado.
- Mashed: Boil first, then mash with olive oil or a little butter. This method is particularly practical for people who struggle with texture or are cooking for kids.
- Air-fried: This is a popular option that uses high-speed hot air circulation to crisp the outside while keeping the inside tender, using far less oil than traditional frying. Air-frying does expose sweet potatoes to high heat, so some beta-carotene loss is expected, like with baking. That said, tossing the pieces in a light coat of oil before air-frying helps with both flavor and absorption.
Our Expert Take
Sweet potatoes do a lot of work. One medium potato delivers 100% or more of your daily vitamin A requirement, plus fiber, potassium and a host of antioxidants. Since beta-carotene is a fat-soluble nutrient, you need to pair your sweet potato with a food that contains fat, like oil, avocado or nuts, in order to maximize absorption.
The science is clear: Boiling or steaming sweet potatoes with the skin on, then pairing them with a small amount of healthy fat, is the combination most likely to protect and enhance vitamin A absorption. If boiling or steaming isn’t your thing, any method that includes some fat and leaves the skin intact is a meaningful upgrade from eating sweet potatoes plain and peeled.
At the end of the day, as Blatner says, “Don’t get so caught up in the cooking method. Instead, cook sweet potatoes in a way you enjoy them most,” because the bottom line is that you will get the most value from the food you’ll actually eat.
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