26 Aug 2021 Article

I’ve been fascinated with the diet of centenarians. What do centenarians eat that make them live so long? Apparently, it all depends on where in the world you live. There are centenarians in different corners of the world, and their diets differ dramatically. However, there is one thing all these diets have in common: they are based on plants.

In this article I will tell you about one of the healthiest diets on Earth, the traditional Okinawa diet. I will also share its 10 highlights with you. Who knows, maybe you can implement some of them into your daily nutrition practice?

Okinawa islands are one of the five so-called blue zones of the world. Blue zones are places where there is an exceptional number of centenarians, people who live longer than 100 years.

Much of the longevity advantage in Okinawa is thought to be related to a healthy lifestyle, which incorporates a traditional diet, very low in calories yet nutritionally dense. However, dietary changes in the last decennia have been largely adverse, with younger Okinawans developing a higher risk of obesity and other chronic disease risk factors as opposed to older Japanese. As a consequence, there has been a resurgence of interest from public health professionals in the health-enhancing effects of what used to be the traditional Okinawan diet.

Trends in life expectancy

At the moment of writing, the average life expectancy at birth is 73.2 years. Thirty countries have a life expectancy at birth > 80 years. The top five countries are Japan (84.26), Switzerland (83,45) Republic of Korea (83.30), Spain (83.22) and Singapore (83.22).

By 2050 the world will have almost 400 million people aged 80 or above. But, naturally, not all of those people will be in good health. The World Health Organization introduced a method of calculating the average number of years that a person can expect to live in “full health” by taking into account years lived in less than full health due to disease and/or injury. This method is called HALE indicator (Health Adjusted Life Expectancy). The HALE indicator demonstrates that the Japanese have the longest life expectancy in good health: 74 years. They are followed closely by Singapore and the Republic of Korea.┬áThe Japanese are thus the true leaders in life expectancy.

Okinawans: one of the world’s longest-living populations

It is a fact that nutrition is an important regulatory factor related to longevity. Other factors include heredity, environmental conditions, physical activity and stress. Japanese are among the world’s longest-living people. The Japanese with the longest life span used to be those that inhabited the southernmost islands, Japan’s poorest prefecture, known as the Okinawa prefecture, a.k.a. the 47th prefecture, or Ryukyu Islands.

Okinawans are believed to reach old age by avoiding the risk of getting diseases associated with ageing and mortality, such as heart disease, stroke, diabetes and chronic lung disease. Elderly Okinawans are found to have impressively young, clean arteries, low cholesterol, and low homocysteine levels when compared to Westerners. These factors help reduce their risk for coronary heart disease by up to 80% and keep stroke levels low.

Traditionally, the leading occupation of Okinawans was agriculture, and they were working until, or sometimes well into, their eighth decade. They have been known to have a strong sense of dedication to family and friends and have been taking good care of elderly community members. All these factors, of course, also play a role in longevity.

The traditional Okinawan meal

What do centenarians eat actually?

The main carbohydrate source of the Okinawa diet is the sweet potato. In 1949 an Okinawan consumed 849 g of sweet potato a day on average!

The traditional Okinawan meal would typically start with miso soup containing water, miso paste, seaweed, tofu, sweet potato, and/or green leafy vegetables. The main dish is a stir-fried vegetable dish called champuru, based on the available veggies of the given day and often including bitter melon (goya). Champuru is often accompanied by prepared kombu (seaweed sort), and konnyaku (root vegetable) simmered in a hint of oil and bonito dashi broth. The Okinawan cuisine centres around vegetables. Tofu is one of the major protein sources. Small amounts of pork or fish are occasionally present on the table. The most commonly used vegetables are daikon, Chinese okra, pumpkin, burdock, green papaya and green leafy vegetables. The meal would contain hardly any added salt and would be seasoned with herbs, curcuma being one of the most popular, and served with freshly brewed jasmine tea, occasionally followed by a small amount of locally brewed millet brandy called awamori.

Highlights of Okinawan diet

  • Very low caloric intake: In 1949 an Okinawan consumed a diet of 1784 kcal/d on average, with only 39 grams of protein (this generation lived the longest in Okinawa);
  • High consumption of vegetables: > 1 kilo per person a day;
  • High consumption of sweet potatoes;
  • High consumption of legumes, predominantly soy;
  • Moderate consumption of fish products;
  • Low consumption of meat;
  • Very low consumption of dairy products;
  • Moderate alcohol consumption;
  • Regular use of seaweed;
  • High intake (via foods) of carotenoids, Folic acid, vitamin B6, vitamin C, Potassium.

Which Okinawan habit are you going to incorporate first? I, myself, am thinking of starting with consuming (even) more sweet potatoes) But to be serious, I think the most important lesson from the centenarians of Okinawa is: eat predominantly plants and be moderate with other food categories.