This article is all about the Japanese sweet potato. Learn the facts behind its origins, nutritional value, and what other varieties of this vegetable exist.
We’ll clear up typical misconceptions about this tasty food. Learn what differentiates it from so-called traditional sweet potatoes; and how it can fit into your diet.
Lastly, we include two appetizing methods of cooking it. Read onwards to get the facts on this delectable source of nourishment.
Table of Contents
What Is the Japanese Sweet Potato?
Dioscorea japonica goes under several common names. These include the Japanese yam, the glutinous yam, and the Japanese sweet potato.
This exotic vegetable originally hails from China and Japan. Scientifically speaking, it’s neither a typical white potato nor a sweet potato.
White potatoes are tubers from the nightshade family. Sweet potatoes are roots originating from the Convolvulaceae or Juss family.
As a member of the Dioscorea family, D. japonica is officially a yam. A yam is any one of many edible tubers produced by plants within this classification.
Different Types of Sweet Potato
True sweet potatoes are all essentially the same plant but cultivated differently. There are thousands of varieties of Ipomoea batatas.
There are five widespread types we use in our kitchens. Learn more about the Purple Stokes, Garnet, Hannah, and Jewel sweet potatoes below:
Purple Stokes are named after their distinctive purple exteriors. They have a rich flavor and a drier texture when cooked.
These sweet potatoes have vivid orange flesh. Garnets are exceptionally sweet to the taste and stay moist when cooked—similar to squash.
Hannahs have white flesh that will turn yellow, like a regular potato, when baked. They share a comparable consistency with white potatoes too: starchy and dense.
Despite the attention-grabbing name, Jewel sweet potatoes are somewhat bland. The flesh is burnt orange in color, with matching coppery outer skin.
Traditional Sweet Potatoes vs Japanese Sweet Potato
To begin with, defining a traditional sweet potato isn’t a straightforward as you may think. They can come in all colors and shapes—from red and purple to orange and brown.
Taste and texture can also vary dramatically, as we’ve detailed above. Still, there are three ways in which the Japanese sweet potato differs from its traditional counterparts.
Botanical classification and nutritional value are the most obvious aspects. It’s also unique in taste, color, and shape.
As we covered earlier, almost every vegetable sold as sweet potato is a breed of Ipomoea batatas. Japanese sweet potatoes are yams, and wholly unrelated to the species or the morning glory family from which it hails.
Nutritional Value of Sweet Potatoes
As yams, they don’t have the same nutritional value as batatas. Most notably, they’re higher in carbohydrates.
The average yam has a comparatively higher 27 grams worth of carbs for the same quantity. That doesn’t mean that they aren’t nutritious, but you may need to adopt a moderate approach on certain diets.
They’re also dissimilar when it comes to vitamins and minerals. Yams of any sort tend to contain more potassium and less sodium—but less bone-building calcium too. As a tradeoff, sweet potatoes are usually richer in vitamins A and B9.
Note that these values may not apply equally to all cultivars (types) of sweet potato. Some are lower or higher—there are too many of them to generalize.
Color and Shape
Japanese sweet potatoes bear a slight resemblance to Purple Stokes. Both types have characteristic purple skins.
However, Japanese yams have a stouter, rounded shape as opposed to an elongated one. The vast majority of traditional sweet potatoes are elongated, and some can grow quite large.
Taste and Texture
The flavor of these edible tubers are particular in that they’re extraordinarily sweet. This is somewhat ironic, considering that they’re officially yams.
The white inner flesh remains firm even after being cooked. It doesn’t flake or soften much, as with certain other sweet potatoes.
Japanese Sweet Potato Nutrition Facts
Aside from taste, a food’s most important feature is how nutritious it is. Japanese sweet potatoes don’t disappoint in either respect.
One hundred grams worth of this purple veggie adds up to 118 calories. The same quantity is also potassium-rich: 816 milligrams, to be precise.
That portion will also give you a small dose of essential vitamins A, B12, and K. An added bonus is that these yams are wholly fat-free.
They’re also full of antioxidants and contain an enzyme that has the ability to lower blood pressure.
Are Japanese Sweet Potatoes Paleo-Friendly?
A Paleo way of life means replicating the diets of our long-distant Paleolithic ancestors. Since D. japonica isn’t refined or processed, you’re welcome to indulge yourself.
You can always check if a food is paleo or not using the Paleo Diet Food List app.
Are Japanese Sweet Potatoes Keto-Friendly?
How to Cook Japanese Sweet Potato
Get ready to relish the sweet, savory taste of this colorful yam. There are plenty of ways to dine on Japanese sweet potato—it’s as versatile as it is colorful.
We’ve stuck with two of the simplest, most popular methods of enjoying it. Either roast it or bake it and chow down:
- Preheat your oven to 400 degrees Fahrenheit.
- Prick your Japanese sweet potatoes liberally with a fork.
- Space them out on a baking sheet (preferably parchment-lined).
- Roast for up to one hour.
- Remove from the oven and split the skins.
- Serve and tuck in. Add your oil of choice or spices as needed.
- Skin and slice up your Japanese sweet potatoes.
- Season with your salt, pepper, and your preferred oil. Add more herbs and spices to the mix if you want.
- Preheat your oven to 425 degrees Fahrenheit.
- Spread your homemade fries on a sheet pan lined with a baking sheet.
- Bake for 30 minutes total, flipping them over at the 15-minute mark.
- Serve and enjoy.
Whether you baked it, roast it, pair it with meat or eggs, the Japanese sweet potato is filled with nutrients and a great way to add some starchy carbs to your plate.
Other Japanese Sweet Potato Resources
Other resources you might like
Other Food Guides at Ultimate
Download Your FREE Paleo Starter Kit Today!
- 3-Day Paleo Diet Meal Plan
- Comprehensive Paleo Diet Shopping List
- 5 of Our Favorite Paleo Diet Recipes