The sweet potato (Ipomoea batatas) is an underground tuber.

It’s rich in an antioxidant called beta carotene, which is very effective at raising blood levels of vitamin A, particularly in children (1, 2, 3, 4).

Sweet potatoes are nutritious, high in fiber, very filling, and delicious. They can be eaten boiled, baked, steamed, or fried.

Sweet potatoes are usually orange but also found in other colors, such as white, red, pink, violet, yellow, and purple.

In some parts of North America, sweet potatoes are called yams. However, this is a misnomer since yams are a different species.

Sweet potatoes are only distantly related to regular potatoes.

This article tells you everything you need to know about sweet potatoes.

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The nutrition facts for 3.5 ounces (100 grams) of raw sweet potatoes are (5):

  • Calories: 86
  • Water: 77%
  • Protein: 1.6 grams
  • Carbs: 20.1 grams
  • Sugar: 4.2 grams
  • Fiber: 3 grams
  • Fat: 0.1 grams

Carbs

A medium-sized sweet potato (boiled without the skin) contains 27 grams of carbs. The main components are starches, which make up 53% of the carb content.

Simple sugars, such as glucose, fructose, sucrose, and maltose, comprise 32% of the carb content (2).

Sweet potatoes have a medium to high glycemic index (GI), varying from 44–96. The GI is a measure of how fast your blood sugar levels rise after a meal (6).

Given the relatively high GI of sweet potatoes, large amounts in a single meal may be unsuitable for people with type 2 diabetes. Notably, boiling seems to be associated with lower GI values than baking, frying, or roasting (7).

Starch

Starches are often split into three categories based on how well they’re digested. The starch proportions in sweet potatoes are as follows (8, 9, 10, 11):

  • Rapidly digested starch (80%). This starch is quickly broken down and absorbed, increasing the GI value.
  • Slowly digested starch (9%). This type breaks down more slowly and causes a smaller rise in blood sugar levels.
  • Resistant starch (11%). This one escapes digestion and acts like fiber, feeding your friendly gut bacteria. The amount of resistant starch may increase slightly by cooling the sweet potatoes after cooking.

Fiber

Cooked sweet potatoes are relatively high in fiber, with a medium-sized sweet potato containing 3.8 grams.

The fibers are both soluble (15–23%) in the form of pectin, and insoluble (77–85%) in the form of cellulose, hemicellulose, and lignin (12, 13, 14).

Soluble fibers, such as pectin, may increase fullness, decrease food intake, and reduce blood sugar spikes by slowing your digestion of sugars and starches (15, 16).

A high intake of insoluble fibers has been associated with health benefits, such as a reduced risk of diabetes and improved gut health (17, 18, 19, 20, 21).

Protein

A medium-sized sweet potato holds 2 grams of protein, making it a poor protein source.

Sweet potatoes contain sporamins, unique proteins that account for more than 80% of their total protein content (14).

The sporamins are produced to facilitate healing whenever the plant is subjected to physical damage. Recent research suggests that they may have antioxidant properties (22).

Despite being relatively low in protein, sweet potatoes are an important source of this macronutrient in many developing countries (14, 23).

SUMMARY Sweet potatoes are mainly composed of carbs. Most of the carbs come from starch, followed by fiber. This root vegetable is also relatively low in protein but still an important protein source in many developing countries.

Sweet potatoes are an excellent source of beta carotene, vitamin C, and potassium. The most abundant vitamins and minerals in this vegetable are (24, 25, 26, 27, 28):

  • Pro-vitamin A. Sweet potatoes are rich in beta carotene, which your body can convert into vitamin A. Just 3.5 ounces (100 grams) of this vegetable provides the recommended daily amount of this vitamin.
  • Vitamin C. This antioxidant may decrease the duration of the common cold and improve skin health.
  • Potassium. Important for blood pressure control, this mineral may decrease your risk of heart disease.
  • Manganese. This trace mineral is important for growth, development, and metabolism.
  • Vitamin B6. This vitamin plays an important role in the conversion of food into energy.
  • Vitamin B5. Also known as pantothenic acid, this vitamin is found to some extent in nearly all foods.
  • Vitamin E. This powerful fat-soluble antioxidant may help protect your body against oxidative damage.
SUMMARY Sweet potatoes are an excellent source of beta carotene, vitamin C, and potassium. They are also a decent source of many other vitamins and minerals.

Like other whole plant foods, sweet potatoes contain a number of plant compounds that may affect your health. These include (12, 31, 32):

  • Beta carotene. An antioxidant carotenoid that your body converts into vitamin A. Adding fat to the meal can increase your absorption of this compound.
  • Chlorogenic acid. This compound is the most abundant polyphenol antioxidant in sweet potatoes.
  • Anthocyanins. Purple sweet potatoes are rich in anthocyanins, which possess strong antioxidant properties.

Notably, the antioxidant activity of sweet potatoes increases with the color intensity of their flesh. Deep-hued varieties, such as purple, deep orange, and red sweet potatoes, score the highest (1, 29, 30).

The absorption of vitamin C and some antioxidants increases in sweet potatoes after cooking, while levels of other plant compounds may decrease slightly (33, 34, 35, 36).

SUMMARY Sweet potatoes are rich in many plant compounds, such as beta carotene, chlorogenic acid, and anthocyanins.

Many people substitute regular potatoes for sweet potatoes, believing sweet potatoes to be the healthier choice.

The two species contain similar amounts of water, carbs, fat, and protein (5).

Notably, sweet potatoes sometimes have a lower GI and boast higher amounts of both sugar and fiber.

Both are good sources of vitamin C and potassium, but sweet potatoes also provide excellent amounts of beta carotene, which your body can transform into vitamin A.

Regular potatoes may be more filling but may also harbor glycoalkaloids, compounds that can be harmful in large amounts (37, 38).

Because of their fiber and vitamin contents, sweet potatoes are often considered the healthier choice between the two.

SUMMARY Sweet potatoes are likely healthier than regular potatoes. They have a lower GI, more fiber, and large amounts of beta carotene.

Sweet potatoes are associated with multiple benefits (39).

Prevention of vitamin A deficiency

As vitamin A plays an important role in your body, deficiency in this essential nutrient is a major public health issue in many developing countries (40).

Deficiency can cause both temporary and permanent damage to your eyes and even lead to blindness. It can also suppress immune function and increase mortality, especially among children and pregnant and lactating women (14, 40).

Sweet potatoes are an excellent source of highly absorbable beta carotene, which your body can convert into vitamin A.

The intensity of the yellow or orange color of the sweet potato is directly linked to its beta carotene content (41).

Orange sweet potatoes have been shown to increase blood levels of vitamin A more than other beta carotene sources, as they contain a highly absorbable variety of this nutrient (42).

This makes eating sweet potatoes an excellent strategy against vitamin A deficiency in developing countries.

Improved blood sugar regulation

Imbalance in blood sugar levels and insulin secretion are the main characteristics of type 2 diabetes.

Caiapo, a type of sweet potato with white skin and flesh, may improve symptoms in people with type 2 diabetes.

This sweet potato may not only decrease fasting blood glucose and LDL (bad) cholesterol levels but also increase insulin sensitivity (43, 44, 45).

However, the current data doesn’t justify the use of sweet potatoes in the treatment of type 2 diabetes. Further human research is needed (46).

Reduced oxidative damage and cancer risk

Oxidative damage to cells is often associated with increased risk of cancer, which occurs when cells divide uncontrollably.

Diets rich in antioxidants, such as carotenoids, are associated with a lower risk of stomach, kidney, and breast cancers (47, 48, 49, 50).

Studies indicate that sweet potatoes’ potent antioxidants may reduce your risk of cancer. Purple potatoes have the highest antioxidant activity (14, 51).

SUMMARY Sweet potatoes may have a variety of benefits, including improved blood sugar regulation and reduced oxidative damage.

Sweet potatoes are well tolerated in most people.

However, they are considered fairly high in substances called oxalates, which may increase your risk of kidney stones (52).

Individuals who are prone to getting kidney stones may want to limit their sweet potato intake.

SUMMARY Sweet potatoes are widely considered safe but may increase your risk of kidney stone formation due to their oxalate content.

Sweet potatoes are underground tubers that are excellent sources of beta carotene, as well as many other vitamins, minerals, and plant compounds.

This root vegetable may have several health benefits, such as improved blood sugar regulation and vitamin A levels.

Overall, sweet potatoes are nutritious, cheap, and easy to incorporate into your diet.