Are Japanese Sweet Potatoes Similar to American Yams?

The Japanese sweet potato is similar to the U.S. yam but has a red skin and a low moisture content. It is delicious baked, mashed, or fried, and can be purchased at most grocery stores. While it resembles the purple-flesh Okinawa sweet potato, it is not the same. Although it is often called a yam, it is not a true yam.

The differences between Japanese sweet potatoes and yams are based on color. The former have purple skins and white interiors while the latter have a rough bark-like skin. The former are starchy, sweet, and low-calorie and have lower sugar and blood pressure than the latter. Nonetheless, yams are not true sweet potatoes. They fall into the nightshade family, which includes red, yellow, and blue-skinned varieties.

While yams originated in China, the Japanese sweet potato has many names, including “Japanese yam” and “glutinous yam.” They are not related to the morning glory family, but are in the nightshade family. In addition to being a source of vitamin A and fiber, Japanese sweet potatoes are also rich sources of potassium, calcium, and fiber. Though the vegetable is much different from the regular yam, it still has great health benefits.

Although there are no clinical trials to support the health benefits of the Japanese sweet potato, research on animal models shows that they are similar to the yam. The difference between the two types is largely in color and texture. The sweet potato is usually smaller and has a rough brown skin, while the true yams have a starchy texture and a deep orange skin. If you live in Okinawa, you might have access to these varieties, which can be found at many Asian supermarkets and farmers markets.