Although “sweet potato” and “yam” are often used interchangeably, they are different vegetables. Sweet potatoes are easier to find and a bit more nutritious. Yams are starchier but still tasty and nourishing.
Yams and sweet potatoes belong to different plant families and are only distantly related.
So why all the confusion? This article explains the key differences between sweet potatoes and yams.
Sweet potatoes, also known by the scientific name Ipomoea batatas, are starchy root vegetables.
Surprisingly, sweet potatoes are only remotely related to potatoes.
Like regular potatoes, the tuberous roots of the sweet potato plant are eaten as vegetables. Their leaves and shoots are also sometimes eaten as greens.
However, sweet potatoes are a very distinctive-looking tuber.
They are long and tapered, with smooth skin that can vary in color from yellow, orange, red, brown, purple, or beige. Depending on the type, the flesh can range from white to orange to even purple.
There are two main types of sweet potatoes: dark-skinned sweet potatoes with orange flesh and golden-skinned sweet potatoes with pale flesh.
Dark-skinned sweet potatoes with orange flesh
Compared to golden-skinned sweet potatoes, dark-skinned sweet potatoes are softer and sweeter with a darker, copper-brown skin and bright orange flesh.
They tend to be fluffy and moist when cooked and are commonly found in the United States
Golden-skinned sweet potatoes with pale flesh
This type of sweet potato is firmer with a golden skin and light yellow flesh. It tends to have a drier texture and is less sweet than dark-skinned sweet potatoes.
Regardless of the type, sweet potatoes are generally sweeter and moister than regular potatoes.
They are an extremely robust vegetable. Their long shelf life allows them to be sold year-round. If stored correctly in a cool, dry place, they can keep for up to 2 to 3 months.
You can buy them in a wide range of different forms, most often whole or sometimes pre-peeled, cooked, and sold in cans or frozen.
Yams are also a tuber vegetable. There are over 600 varieties, which vary widely in size.
Compared to sweet potatoes, yams can grow very large. Size can vary from that of a small potato to up to 5 feet (1.5 meters).
Yams have some distinct characteristics that help distinguish them from sweet potatoes, mainly their size and skin.
They are cylindrical in shape, with brown, rough, bark-like skin that is difficult to peel but softens after heating. The flesh color varies from white or yellow to purple or pink in mature yams.
Yams have a unique taste, too. Compared to sweet potatoes, yams are less sweet and much more starchy and dry.
They also tend to have a good shelf life. However, certain varieties store better than others.
In the United States, true yams can be tough to find. They are imported and rarely found in local grocery stores. Your best chances of finding them are in international or ethnic food stores.
There is so much confusion surrounding the terms sweet potatoes and yams. Both names are used interchangeably and are often mislabeled in supermarkets.
Yet, they are completely different vegetables.
A few reasons can explain how this mix-up happened.
Africans who were enslaved and brought to the United States called the local sweet potato “nyami,” which translates to “yam” in English. This is because it reminded them of true yams, a food staple they knew in Africa.
The darker-skinned, orange-fleshed sweet potato variety was only introduced in the United States several decades ago. To set it apart from paler-skinned sweet potatoes, producers labeled them “yams.”
The term “yam” is now more of a marketing term for producers to distinguish between the two types of sweet potatoes.
Most vegetables labeled as a “yam” in the United States are actually just a variety of sweet potato.
Both sweet potatoes and yams are very versatile. They can be prepared by boiling, steaming, roasting, or frying.
Sweet potatoes
The sweet potato is more commonly found in the United States, so it’s used in a wider range of traditional Western dishes, both sweet and savory.
It’s most often baked, mashed, or roasted. It can also be puréed and used in soups and desserts. Sweet potato fries, an alternative to baked or mashed potatoes, are another popular method of cooking.
As a staple on the Thanksgiving table, sweet potatoes are most often served in a casserole with marshmallows or made into a sweet potato pie.
Yams
True yams are rarely found in Western supermarkets. However, they are a staple food in other countries, particularly those in Africa.
Their long shelf life allows them to be a steady food source.
In Africa, purple yams are most often boiled, roasted, or fried. They’re more commonly found in Japan, Indonesia, Vietnam, and the Philippines and are often used in desserts.
Yams can be bought in various forms, including whole, powder, or flour, and as a supplement.
Yam flour is available in the West from grocers specializing in African products. It can be used to make dough that is served as a side with stews or casseroles, and it can also be used similarly to instant mashed potatoes.
Wild yam powder can be found in some health food and supplement stores under various names. These include wild Mexican yam, colic root, or Chinese yam.
100 grams of
- water: 79.5 grams
- carbohydrates: 17.3 grams
- protein: 1.58 grams
- fiber: 4.44 grams
- fat: 0.38 gram
- sugars: 6.06 grams
- calcium: 22 milligrams
- iron: 0.4 milligrams
- magnesium: 19.1 milligrams
- vitamin C: 14.8 milligrams
- vitamin K: 0.2 micrograms
- potassium: 486 milligrams
- water: 69.6 grams
- carbohydrates: 27.9 grams
- protein: 1.53 grams
- fiber: 4.1 grams
- fat: 0.17 gram
- sugars: 0.5 grams
- calcium: 17 milligrams
- iron: 0.54 milligrams
- magnesium: 21 milligrams
- vitamin C: 17.8 milligrams
- vitamin B-6: .293 milligrams
- vitamin A: 7 micrograms
- potassium: 816 milligrams
Sweet potatoes are rich in vitamins, minerals, and fiber, as well as vitamin C, potassium, and beta carotene, which converts to
In fact, one 3.5-ounce (100-gram) serving of sweet potato will supply you with almost all of your daily recommended amount of vitamin A, which is important for vision and the immune system.
Both sweet potatoes and yams have decent amounts of other micronutrients, such as B vitamins, which are vital for many bodily functions, including producing energy and creating DNA.
In addition to the nutrient content of sweet potatoes and yams, it’s also important to consider the glycemic index (GI) of each. The GI of a food gives an idea of how slowly or quickly it affects your blood sugar levels.
GI is measured on a scale of 0 to 100. A food has a low GI if it causes blood sugars to rise slowly, whereas a high GI food causes blood sugars to rise quickly.
Cooking and preparation methods can cause a food’s GI to vary. For example, baked sweet potatoes have a medium-to-high GI, varying from 58 to 91, whereas yams have a low-to-medium GI, ranging from 55 to 67.
Boiling, rather than baking, frying, or roasting, is linked to a lower GI for both yams and sweet potatoes.
Sweet potatoes are a great source of highly available beta-carotene, which can increase vitamin A levels. This can be very important in developing countries where vitamin A deficiency is common.
Sweet potatoes are also rich in antioxidants, particularly carotenoids, which are thought to help protect against heart disease and decrease the risk of cancer.
Certain types of sweet potatoes, especially purple varieties, are thought to be the highest in antioxidants, much higher than many other fruits and vegetables.
Also, some studies suggest that certain types of sweet potatoes can help improve blood sugar regulation and reduce “bad” LDL cholesterol in people with type 2 diabetes.
Health benefits of yams
Meanwhile, the health benefits of yams have not been extensively studied.
There is limited evidence that yam extract may be a helpful remedy for some of the symptoms of menopause.
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It’s important to remember that this was a small study, and more evidence is needed to confirm these health benefits.
Learn more about the health benefits of yams and sweet potatoes
Although sweet potatoes and yams are considered healthy and safe foods to consume for most people, it may be wise to follow certain precautions.
For example, sweet potatoes have fairly high levels of oxalates. These are naturally occurring substances that are usually harmless. However, when they accumulate in the body, they can cause problems for people at risk of kidney stones.
Precautions must also be taken when preparing yams. While sweet potatoes can be safely eaten raw, certain types of yams are only safe when cooked.
Naturally occurring plant proteins found in yams can be toxic and cause illness if consumed raw. Peeling and cooking yams thoroughly will remove any harmful substances.
Sweet potatoes and yams are completely different vegetables. However, they’re both nutritious, tasty, and versatile additions to the diet.
Sweet potatoes tend to be more readily available and are nutritionally superior to yams — albeit only slightly. If you prefer a sweeter, fluffier, and moister texture, opt for sweet potatoes.
Yams have a starchier, drier texture but might be harder to find.
You really can’t go wrong with either.
