By Dr. Mercola
Whenever I find information that will help promote optimal health, I am always eager to share it with all of my readers. This is especially true when it comes to diet, as proper nutrition is one of the pillars of good health and wellness. Now, I am excited to share with you the potential health benefits of sweet potatoes.
Sweet Potatoes: More Than Just Food for the Holidays
When consumed in moderation, sweet potatoes can provide a rich concentration of nutrients. This makes them an ideal addition to your meals throughout the year. A substantial amount of research has proven that these naturally-sweet root vegetables possess antioxidant, anti-inflammatory, and disease-fighting components.1, 2, 3
The Sweet Potato's Humble Beginnings
The cultivation of sweet potatoes dates back to 750 BC, making it one of the oldest foods known to man.4 After Christopher Columbus' introduction of yams to Europe, the Spanish and Portuguese explorers brought sweet potatoes to different parts of the world, including Asia and Africa.5 In the 16th century, the United States – particularly in the southeastern part – consumed sweet potatoes as a staple food.6
About 400 varieties of sweet potatoes have been discovered, with some rarer than others.7 They are set apart using the appearance of their skin and color, including cream, tan, yellow, orange, pink, and purple.8 While they are in season during the months of November and December, they are available all-year round in local markets.
The Sweet Potato vs. Yams and Regular Potatoes
Sweet potatoes are often mistaken as "yams," which are the starchy root vegetables from the Dioscoreae family. Sweet potatoes belong to the Convolvulaceae or morning glory plant family. They possess two seed leaves, while yams only have one embryonic seed leaf and are moister.9
Yams are native to Africa, Asia, and tropical regions. They, too, have numerous varieties – the more familiar ones appear with dark, rough skin and white, purple, or red flesh.10
Generally, most sweet potatoes have the same size and shape. Yams, in contrast, may be as big as regular potatoes or may grow up to five feet long.11 Sweet potatoes also vary from regular potatoes, despite similarities in calorie, carbohydrate, and fiber content. The former is often considered healthier than the latter.
The calories and salt content of regular potatoes increase when they are fried. Regularly eating them fried may put you at risk or high blood pressure, cardiovascular disease, and stroke.12 This does not happen with sweet potatoes. Another reason why sweet potatoes are considered superior to regular potatoes is their varying colors, which indicate the presence of potent antioxidants.13
What Is the Significance of the Vibrant Colors of Sweet Potatoes?
Orange-colored sweet potatoes owe their appearance to the carotenoid beta-carotene. Carotenoids are natural pigments responsible for the colorful appearances of some fruits and vegetables.
As an antioxidant, beta-carotene can help ward off free radicals that damage cells through oxidation, which can speed up aging and make you vulnerable against chronic diseases. This antioxidant can help support your immune system, as well as lower your risk of heart disease and cancer.14
Beta-carotene can be converted into retinol or vitamin A by your body,15 and vitamin A contributes to optimal eye health and vision. While taking vitamin A in large doses can be toxic, receiving it from beta-carotene is considered safe due to your body's ability to regulate its vitamin A production.16
Sweet potatoes can also contribute to skin health. Vitamin A, which is a natural anti-inflammatory, can help get rid of acne-causing bacteria.17
Purple sweet potatoes, on the other hand, contain anthocyanins, another type of natural pigments. Anthocyanins are associated with reduced cancer risk. Studies show they help suppress stomach, colon, lung, and breast cancer cell proliferation.18 They also prevent blood clots by stopping platelets from clumping together – a function that may help fight heart disease.19
Other Beneficial Compounds Found in Sweet Potatoes
While orange sweet potatoes have anti-carcinogenic properties, it was found that purple sweet potatoes have better cancer-fighting abilities because they have cyanidins and peonidins, which have a positive effect against cancer cell growth.
These cancer-fighting compounds, which are more prevalent in the flesh than in the skin,20 are found to help reduce the potential dangers of heavy metals, such as mercury, cadmium, and arsenic. This is beneficial to individuals diagnosed with digestive problems like irritable bowel syndrome and ulcerative colitis, as well as to those who wish to reduce their exposure to metal toxins.21
Sweet potatoes also contain two important antioxidant enzymes: copper/zinc superoxide dismutase and catalase. According to one study, purple sweet potatoes have more than three times the antioxidant activity than that of one blueberry.22 In addition to sweet potatoes' antioxidant content, these vegetables are also great sources of vitamins C and B5, copper, dietary fiber, niacin, potassium, and iron.23
Sweet Potatoes Can Address Inflammation, Too
One study published in the Journal of Medicinal Food report that sweet potatoes have anti-inflammatory potential because of their concentration of nutrients. Sweet potato extract is said to help reduce inflammation in brain and nerve tissue throughout your body.24 The phytonutrients within sweet potatoes also influence fibrinogen, an important glycoprotein required for blood clotting. Together with thrombin and fibrin, balanced amounts of fibrinogen are important for wound healing and blood loss prevention.
Are Sweet Potatoes Safe for Diabetics and Pre-Diabetics?
According to research conducted in the College of Agriculture and Life Sciences, sweet potatoes are a low-glycemic index (GI) food, which release glucose very slowly into the bloodstream.25 Low-glycemic foods also benefit the pancreas by not overworking it and make you feel satiated longer.26
Other research shows that sweet potatoes can help regulate blood sugar because of their ability to raise blood levels of adiponectin, a protein hormone created by your fat cells, to help regulate how your body metabolizes insulin.27
Even if these findings exist, sweet potatoes should still be consumed in moderation. Keep in mind that the sweet potato is a naturally sweet food and its varieties differ with their sugar content. An example is the American sweet potato, which is grown because of its sweetness. It contains 6.5 grams of sugar per 100 grams.28
If you're a diabetic or are suffering from problems related to insulin resistance, consult your doctor to know whether it's safe for you to consume sweet potatoes.
Cooking Sweet Potatoes: How to Increase the Bioavailability of Their Nutrients
The method of cooking or preparation is as important as the food you eat, as this can greatly impact the quality of your meals. Sweet potatoes are no exception.
Peeling can make the sweet potato's flesh susceptible to oxidation, which can induce dark spots. It is recommended that sweet potatoes be steamed, baked, or placed in water immediately after peeling.31
Since beta-carotene is fat-soluble, I advise consuming sweet potatoes with fat – about three to five grams of fat is sufficient. Fat-soluble nutrients require fat to be absorbed effectively in your body. I recommend using raw butter from grass-fed cows when enjoying sweet potatoes.
Pureed sweet potatoes, along with mashed avocadoes and cooked peas or carrots, are ideal choices for infants starting with solid food. Also, consider cooking sweet potatoes or squash and putting it into an ice cube tray to have ready-made servings available for your baby throughout the week. 32
Sweet Potato Recipes to Try at Home
If you're fond of eating sweet potatoes during Thanksgiving, you will surely love having them as a snack at any time of the year. Here's a taste and easy recipe for homemade sweet potato from Instructables.com.
Perfect Oven Sweet Potato Fries
• One sweet potato
• Sea salt, coarse
• Black pepper, ground
• Olive oil (Coconut oil can serve as a better option)
1. Preheat the oven to 450 degrees Fahrenheit. You may or may not peel the potato.
2. Cut the potato into large chunks about 1/2 to 3/4 inches thick.
3. Place the sweet potato fries into the baking sheet and sprinkle a pinch of sea salt and apply the ground black pepper. Next, drizzle the fries with about 1/8 cup of oil. You may add more if you wish.
4. Place in the oven for 15 minutes. Afterward, take them out and flip and return to oven for 10 minutes.
May take 1 hour and a half to make and can serve 2 to 3 people.
Here's another one that can give you a great sweet potato experience!
Grilled Coconut Sweet Potato Kabobs
• 2 or 3 sweet potatoes, peeled and cut into 1 to 2 inch pieces.
• Flaked coconut, unsweetened
• 1 one-pint container of plain Greek yogurt
• 1 tbsp. of coconut oil
1. First, pre-heat your grill to medium-high. Stream the sweet potato chunks in a small amount of water, stovetop, for 10 minutes.
2. Next, allow the chunks to cool. Place them on wooden or metal skewers. Baste them with Greek yogurt and drizzle with coconut oil. Grill them until they become lightly browned and crispy on the surface. It will take about four minutes on each side.
3. Then, roll the entire skewer gently on a plate liberally sprinkled with the coconut flakes. You may season with salt if you wish.
Consuming sweet potatoes is an excellent way to obtain potent antioxidants like beta-carotene and anthocyanins. While given this nutritional profile, they should still be consumed in moderation due to their sugar content. Learning about different varieties will help you determine which type is safest among the rest.