The Secret of Longevity in Okinawa: Does the Purple Sweet Potato Support a Century of Life? Learning from the "Purple Staple" Lifestyle of Okinawa's Island of Longevity

A Story of a Sweet Potato from the "Island of Longevity"

It is well-known that Okinawa, Japan's southern tropical region, is one of the world's leading longevity areas. However, an article published by Brazil's economic media "InfoMoney" in November 2025 became a hot topic by reporting that the main factor supporting this longevity is a very simple food ingredient. The title was "The Simple Food Dominating the Diets of Okinawa's Centenarians." The answer was not steak or luxury supplements, but the **purple sweet potato "beni imo."**InfoMoney.

According to the article, in Okinawa, 67 people per 100,000 live to be over 100 years old. This is a level that significantly exceeds the average longevity rate (about 10-20 people) in many developed countriesJuxtaposition, attracting the interest of researchers worldwide who wonder, "Why does time flow differently on this island?"

Why is Okinawa so long-lived?

Of course, there is not just one reason. Genetics, climate, community connections, post-war history... various factors overlap. However, research focusing on diet has consistently pointed out the characteristics of being **"plant-based," "low-calorie," and "low in processed foods."**PMC.

Among these, the main role is played by the beni imo. An estimate suggests that in the 1950s, sweet potatoes accounted for about 60-70% of the total calorie intake in OkinawaBusiness Insider. In other words, the people of Okinawa at that time did not follow the typical Japanese style of "rice with side dishes,"but used sweet potatoes themselves as their staple food.

What is the small "nutritional factory" of purple beni imo?

Beni imo looks like an ordinary sweet potato, but when cut, its inside is a vivid purple color. The secret of this color isanthocyanin, a polyphenolic antioxidant. It is the same pigment found in blueberries and grapes, and is believed to reduce oxidative stress on cells and lower the risk of cardiovascular diseases and some cancersThe Vitallist.

The InfoMoney article introduces the following points about the nutrients contained in one serving of beni imoInfoMoney.

• About 22g of qualitycomplex carbohydrates

• Rich in dietary fiber, supporting gut health

• About 2g ofprotein

• Vitamin A and C far exceeding the daily recommended amount

Thanks to this nutritional balance, it provides energy gradually without causing a rapid spike in blood sugar levels. This is well-suited for a lifestyle with a lot of physical activity like farming or housework, and it helps prevent hunger.

"Why sweet potatoes instead of rice?" A dietary habit shaped by history

So why has Okinawa become such an "island of sweet potatoes"?

According to studies like the Blue Zones research, the background includesharsh natural conditions. In subtropical Okinawa, where typhoons are frequent, rice grown in paddies had a high risk of being wiped out by wind and rain. In contrast, sweet potatoes are root vegetables, resistant to wind, and easy to grow in poor soil. Since being introduced from China around the 17th century, they have been considered a "lifeline" crop that saved people from famineBlue Zones.

It is interesting that this history has resulted in a "healthy staple food" for the island. The crop chosen to withstand typhoons has, centuries later, become a "symbol of longevity" attracting global attention, a somewhat ironic stroke of luck.

The Spread of "Beni Imo Longevity Theory" on Social Media—Global Reactions

When the InfoMoney article was published, various reactions were seen on social media in Brazil and Japan (summarized here as typical voices).

Reactions from Brazil

• "I often ate sweet potatoes recommended by my gym trainer, but I didn't know Okinawa's centenarians ate them too! I'll look for the purple ones from now on."

• "It's interesting that simple sweet potatoes are stronger than supplements or luxury proteins. It sounds like a message that basics are best for both investment and health."

• "Since we sell batata-doce roxa (purple sweet potatoes) in Brazil, I want to know Okinawan-style recipes!"

Since the source was an economic media outlet, there were quite a few comments from a financial perspective, such as "health is a kind of asset management."

Reactions from Japan

• "So what my grandmother eats every day was right all along... (laughs)"

• "It's a bit proud that beni imo tarts, which are common in Okinawa, are treated as 'superfoods' overseas."

• "But I've heard that Okinawa now has more fast food and isn't as healthy as it used to be, so preserving the food culture is important."

On Japanese social media, there were noticeable comments expressing pride in local cuisine, as well as concern about the "loss of traditional eating habits."

From a Global Perspective

In English-speaking regions, overlapping with the popularity of Blue Zones, there are many posts like "I want to incorporate Okinawan food, not just the Mediterranean diet" and "I like the idea of hara hachi bu (eating until 80% full)." It is impressive that beni imo is discussed not just as a superfood, but in conjunction with moderate eating habits and community practicesThe Vitallist.

Okinawan-Style Longevity Meals: More Than Just Beni Imo

While beni imo is a symbolic presence, Okinawa's traditional diet is not complete with just that. Comprehensive research highlights the following characteristicsPMC.

• Staple food: Root vegetablescentered around beni imo

• Side dishes: Green and yellow vegetables and seaweedsuch as goya, island carrots, pumpkins, leafy greens, and seaweed

• Protein sources: Soy productslike tofu, miso, and natto, and small amounts of fish and pork

• Fats: Limited animal fats, using lard but in small amounts

• Beverages: Sanpin tea (jasmine tea), green tea, etc.

The InfoMoney article also points out that **"dairy products rarely appear, and industrial vegetable oils are seldom used."**InfoMoney. In other words, beni imo serves as a pillar of energy within this simple and natural dining table.

The Philosophy of Eating: "Hara Hachi Bu" and "Yuimaaru"

When looking only at nutrients, one might think, "So should I just take beni imo supplements?" However, a keyword that repeatedly appears in Okinawan longevity research is **"hara hachi bu (eating until 80% full)."**The Vitallist.

As the saying goes, "No need for a doctor if you eat until 80% full," the habit of putting down your chopsticks before feeling full is a powerful life hack to prevent excess calorie intake. Beni imo, with its good satiety and low impact on blood sugar levels, helps in practicing hara hachi bu by allowing satisfaction with smaller portions.

Additionally, we must not forget the spirit of **"yuimaaru"** rooted in Okinawa. This culture of mutual assistance and community support prevents isolation and protects mental health. Longevity is not just about nutrition; it is also about the "design of society."

"Beni Imo-Like" Habits You Can Start Today

That said, it's not easy to get Okinawan beni imo every day. So, let's consider "beni imo-like" ways to incorporate it that can be mimicked anywhere in the world.

1. Replace part of your staple food with sweet potatoes

• Replace part of your white rice or bread with **sweet potatoes (preferably purple ones).**

• Example: Halve your dinner rice and add steamed sweet potatoes.

Even this can significantly increase your intake of dietary fiber and antioxidants.

2. Choose "steaming or baking" over frying

To make the most of the nutrients, choose cooking methods likesteaming or baking. Sweet potato fries are delicious, but they quickly increase calories and fat. In Okinawan households, it's common to simply steam them and serve with miso or enjoy them as a tea snack.

3. Eat with vegetables & beans

The key is not to eat large amounts of beni imo alone, but tocombine it with vegetables and beans. For example:

• Beni imo + goya chanpuru-style tofu stir-fry

• Purple sweet potato salad (using soy milk mayo or miso dressing instead of yogurt)

This way, you can also get a balanced intake of protein and minerals.

4. Replace "snacks"

Instead of eating chocolate or snacks, havea small baked sweet potato. Its strong sweetness provides high satisfaction, and it doesn't cause rapid fluctuations in blood sugar levels.

Caution: Beni Imo is not a panacea