Is the Okinawan Diet the Key to a Long & Healthy Life?

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At the time of writing this post I was staying in Okinawa, which is a string of subtropical islands between Japan and Taiwan. These islands have a reputation for being a ‘Blue Zone’, which is an area where people live longer and healthy lives, like the Mediterranean. This is often attributed to the traditional Okinawan diet.

But is there good evidence to back this up? Read on to find out!

 

What is the Traditional Okinawan Diet?

The main features of this diet are:1,2 

  • A high intake of fruit and vegetables – especially shiitake mushrooms, beni imo (a purple sweet potato) and goya (bitter melon). Beni imo is low GI, and high in fibre, vitamin C, potassium and carotenoids (plant pigments that can be used as anti-oxidants or converted into vitamin A). Goya is low in calories but high in vitamin C and fibre.
  • A high consumption of legumes – mainly soy-based products such as tofu and edamame beans.
  • A moderate intake of fish and seafood – including octopus and squid.
  • A lower intake of rice than the rest of Japan.
  • Seaweed – such as kelp and komu.
  • A low intake of meat- this was mainly eaten on special occasions, with pork and pig’s ear being particularly popular.  
  • A low intake of dairy.
  • Konnyaku – a type of jelly made from a root vegetable called ‘devil’s tongue’.
  • Herbs and spices – such as miso, turmeric and mugwort.  
  • Jasmine tea.
  • Alcohol in moderation.

Click here for the reference for this diagram picture

Overall this diet is high in carbohydrate (roughly 85% of daily calories from carbohydrate), and quite low in protein and fat (especially saturated fat)1,3. This diet is also low in calories, in 1978 it was found that those living in Okinawa consumed 17% less calories than the Japan average4.

There is an emphasis on mindful eating by not eating past the point of fullness. This is highlighted by the the mantra “hara hachi bu” which is used before meals, this meals to stop eating when you are 80% full5.

Similar to the Mediterranean diet, being physically active, socialising, using local produce, managing stress and having a sense of purpose (called ‘ikigai’) are central to the traditional Okinawan way of life5.

Are Okinawans the Longest Living People in the World?

According to the World Health Organisation (WHO), Japan has the highest overall life expectancy in the world at 83.7 years6.

However other countries are not far behind this, such as: Switzerland (83.4 years), Singapore (83.1 years) Italy (82.7 years), Iceland (82.7 years) and Israel (82.5 years). The global average life expectancy is 71.4 years (73.7 years for women and 69.1 years for men)6.

The table below, which is based WHO statistics from 2015, shows that Japanese people have a relatively low risk of dying from chronic diseases such as: heart disease, diabetes, cancer or lung disease6. This also shows that Japan has a fairly high government spend on healthcare. As well as this, Japan’s healthcare system is know for being effective and thorough, which is likely to be an important reason for its long life expectancy7.

Country Average Life Expectancy

% risk of adults dying from chronic disease 

% of Government Budget Spent on Healthcare
Japan 83.7 years

(women = 86.8 years, men = 80.5 years)

8.8% 20.3%
The UK 81.2 years

(women = 83.0 years, men = 79.4  years)

11% 16.5%
Ireland 81.4 years

(women = 83.4 years, men = 79.4years)

10.3% 13.4%
The US 79.3 years

(women = 81.6 years, men = 76.9years)

13.6% 21.3%
Australia 82.8 years

(women = 84.8 years, men = 80.9 years)

8.9% 17.3%

Okinawa had the longest life expectancy in all of Japan for many years. However this changed in 2000 when male life expectancy dropped to 26th out of the 47 prefectures of Japan8. The most recent figures from 2010 found that the avergare male life expectancy in Okinawa was 79.28 years (30th highest life expectancy out of the 47 prefectures), and female life expectancy was 87.2 years (3rd highest life expectancy out of the 47 prefectures)9. Overall life expectancy has continued to rise in Okinawa, as it has in all of Japan, but this is likely to be related to the issue of low birth rates10.

Life expectancy may be reducing in Okinawa compared to other parts of Japan because it has adopted a more Western diet in recent years11.

Another potential reason may be due to an increase in chronic disease (like type 2 diabetes, heart disease and cancer) in those who were born at a low birth rate after world war two12.  

Is There Evidence that the Okinawan Diet is Healthy?

 

Many of the commonly eaten foods in the Okinawan diet are nutritious, especially as it includes a high intake of vegetables.

There is good evidence that a high intake of fruit and vegetables is linked with a lower risk of heart disease, cancer and early death13. A regular intake of soy based foods is also associated with a reduced risk of heart disease14.

There is some evidence that goya and konnyaku may help with lowering blood sugar levels in those with diabetes, but it isn’t clear how this works and this isn’t a safe alternative to diabetes medication15,16. Similarly, turmeric may have some health benefits, but the evidence isn’t very strong for this17.

But research shows that patterns of eating are more important than focusing on individual foods.

Some studies have found health benefits associated with the traditional Okinawan diet, which may be due to the overall mixture of nutrients, as well as the fact that it encourages a healthy lifestyle2 . There are similarities between the traditional Okinawan diet and the Mediterranean diet, such as a good intake of fruit, vegetables, low glycemic index (GI) foods and omega 3 fats; a low intake of processed meat, sugar, salt and saturated fat; as well as regular activity and socialising1.

However, there is more evidence to support the benefits of the Mediterranean diet compared to the Okinawan diet18.  

It is possible that some of the healthy aging benefits of the Okinawan diet are related to calorie restriction, as this has may have an effect on specific pathways in our cells2,19. But the evidence is mixed about whether calorie restriction has a clear role in human health20. Also, the low calorie and low protein content of the Okinawan diet has been linked with poor health outcomes in recent years, such as: malnutrition, low birth weight and poor breastfeeding12

The Current Food Culture in Okinawa

I have only seen a small part of Okinawa and have been staying in a touristy area, so I don’t have firsthand experience of how people eat in rural areas. But from what I’ve seen most of the foods from the traditional Okinawan diet are still eaten, there was even a massive billboard for goya chanpuru near my accommodation (this is a traditional dish made of stir-fried goya, tofu, egg and pork).

 

 

Western food is readily available here, but I have also seen a lot of modern twists using traditional foods. For example, I had a pizza topped with beni imo (purple sweet potato) and goya (bitter melon); and I had beni imo flavoured ice cream (which was very tasty!). Okinawa also seems to be making the most of it’s healthy reputation as there are several  ‘longevity cafes and restaurants’ on the islands.

 

 

In the traditional Okinawan diet meat was mainly eaten on special occasions, whereas it seems to be very popular now (as it is in the rest of Japan as well). Most restaurants serve lots of meat based dishes, including: pig’s ear, wagyu (marbled) beef, meat sushi and spam sushi. The traditional salted Okinawan ice-cream even contains beef and pork fat!

 

 

Spam is a canned meat which was used a lot during world war two, this is made of: pork, potato starch, ham, salt, water, sugar and flavourings. The reason spam is popular here is thought to be because Okinawa’s became the main US military base in Japan after the war (which it still is) and the soldiers used to give Spam to locals. This was clearly a hit, as well as spam sushi there is now a version of Goya Chanpuru made with spam instead of pork.

 

Take Home Message:

The traditional Okinawan diet is similar to the Mediterranean diet and it encourages many healthy foods and positive lifestyle habits, but currently there is more evidence which supports the Mediterranean diet.

Okinawa does have a long life expectancy, but this is no longer the highest in Japan, which may be related to an increase in Western style food.

There isn’t good evidence that specific foods in this diet directly impact our health. So rather than obsessively trying to follow this diet, a healthier approach would be to: eat plenty of fruit and vegetables; include fish and soya based food in your diet; be mindful when you are eating to avoid eating past the point of fullness too often; don’t drink too much alcohol; move your body regularly; socialise and manage stress.  

 

A sunset in Onna (Okinawa)

If you are interesting in finding out more about food in Japan then check out:


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