Okinawa Sweet Potato: Japan’s Amazing Purple Superfood!


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Purple Okinawa sweet potato, some whole, some sliced, on a wooden table.

The Japanese island of Okinawa has one of the longest life expectancies in the world; as such, the traditional Okinawan diet is one of the healthiest. A staple food of this diet? The Okinawa sweet potato, also called beni imo, purple sweet potato, or Hawaiian sweet potato.

The Okinawan sweet potatoes are so nutritious that they even became Hollywood famous. They were featured on the Oprah Winfrey Show in 2009, then Dr. Oz listed them as one of his top five Superfoods of 2010. These purple packets of goodness are nutritious, delicious… and gorgeous.

The skin of the Okinawan sweet potato is creamy beige, but inside, they are vibrantly purple. They instantly elevate any dish’s appearance. The potato’s purple flesh is creamy and sweet, with notes of honey. Learn about these superfood sweet potatoes, their origins and nutritional benefits, and some tasty recipes!

The Origins of the Okinawa Sweet Potato

These vibrant purple sweet potatoes trace their origins back to South America. Historical records reveal an intriguing tale from the 1400s when Spanish explorers introduced these tubers to the Philippines and China after encountering them in the Aztec Empire. With their captivating hue and distinct flavor, purple sweet potatoes swiftly gained popularity in these new lands, leaving a lasting culinary impact many people enjoy today.

A plate of steamed purple Okinawa sweet potato on a plate.
The Okinawa sweet potato gets its purple color from anthocyanin, a natural pigment. Image via Shutterstock

Noguni Sokan, a Japanese government official trading with China, introduced sweet potatoes to Okinawa in the early 1600s. The sweet potatoes thrived in the Okinawan climate, eventually becoming a staple crop and spreading their cultivation to other regions of Japan.

The Okinawa sweet potatoes are not related to regular potatoes, which are a part of the nightshade family. Instead, like other sweet potatoes, they are a part of the morning glory family. Okinawa sweet potatoes are often confused with purple yams, another tuber popular in Okinawa and throughout Southeast Asia. However, while similar in appearance, purple yams are native to Asia. In addition, Okinawa potatoes and purple yams can be referred to as beni-imo in Okinawa.

Purple Sweet Potato Nutritional Information

Like another popular Japanese delicacy, kinako, Okinawan sweet potatoes are perfect for you and are even sweeter than regular sweet potatoes. The antioxidant anthocyanin causes Okinawa sweet potatoes’ beautiful, deep purple color, the same antioxidant found in blueberries, a fruit often praised for its high levels of antioxidants. However, Okinawa sweet potatoes contain 150% more antioxidants than blueberries, which makes them a powerful cancer-fighting superfood.

A bunch of purple sweet potato chips.
Purple sweet potatoes have fantastic health benefits! Image via Shutterstock

These purple sweet potatoes have plenty of other nutritional benefits too. They contain:

  • Four times your daily value of vitamin A,
  • Half your daily value of Vitamin C and manganese,
  • Vitamin B6, copper, and iron,
  • Dietary fiber and potassium.

Studies have also shown that potatoes have antibacterial and antifungal abilities, which may help regulate blood sugar.

What are Hawaiian Sweet Potatoes?

Hawaiian sweet potatoes are a delightful and vibrant root vegetable originating from the beautiful island of Hawaii. These sweet potatoes are distinct for their white skin and purple flesh, differentiating them from other varieties. Packed with flavor and nutritional benefits, Hawaiian sweet potatoes offer a slightly sweet taste and a smooth, creamy texture when cooked.

A split Hawaiian purple sweet potato.
Hawaiian purple sweet potatoes are paler. Image via Shutterstock

Rich in antioxidants, vitamins, and dietary fiber, they are a delicious addition to your meals and provide a healthy boost. Whether roasted, mashed, or used in various culinary creations, Hawaiian sweet potatoes are a versatile and nutritious treat that will leave you craving more.

What are Murasaki Sweet Potatoes?

Murasaki sweet potatoes are a delightful variety that originated in Japan. Generally, they are prized for their vibrant purple flesh, which adds color to any dish. Moreover, these sweet potatoes have a slightly nutty and sweet flavor, making them a versatile ingredient in savory and sweet recipes. Without a doubt, Murasaki sweet potatoes offer great taste and a range of health benefits.

How can I introduce Okinawa sweet potato into my diet?

With all these nutritional benefits, Okinawan sweet potatoes are a great food to include. But how do you cook them? The purple sweet potato can be used in sweet, savory, and traditional Okinawan and Hawaiian dishes. You can use them in your favorite recipes to substitute regular sweet potatoes.

A bowl of mashed purple sweet potatoes.
Purple sweet potatoes almost have a wine-like taste. Image via Shutterstock

Mashed Okinawan sweet potato is a popular and easy side dish from the Hawaiian island of Kauai. Here’s a mashed potatoes recipe for you to try at home:


  • Two medium purple sweet potatoes
  • 1/2 cup coconut milk
  • Salt and sugar to taste (the dish can be served sweet or savory).

How to cook Mashed Okinawa Sweet Potato

  1. Wash the potatoes
  2. Boil the potatoes for 1 hour, until soft
  3. Let cool
  4. Peel off the skin of the potatoes, then mash 
  5. Mix in the coconut milk, sugar, and salt
  6. Chill before serving

The result is a deep purple puree that is the perfect tropical accompaniment for any meal.

Okinawan sweet potatoes are also delicious when gently roasted in the oven. The heat caramelizes their natural sugars (a dish called yaki imo in Japanese). Another popular Okinawan way of serving them is sliced and deep-fried in the batter as tempura. Because purple sweet potatoes are naturally sweet, they are popular in many desserts, including pie, mochi, cheesecake, and Japanese ice cream.

A plate of purple Okinawa sweet potato tarts, also known as beni-imo tarts.
Beni-imo tarts use a sweet potato paste. Image via Shutterstock

One of Okinawa’s most popular desserts and souvenirs is “Beni Imo Tarts,” also called “Purple Sweet Potato Tarts.” Boats of crispy cooks Okinawan sweet potato are topped with a layer of smooth, sweet potato paste to make a snack so good you might eat the whole pack. The tarts are so famous that KitKat has even created its regional flavor mimicking them: a crispy cookie bar with a creamy purple potato coating.

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