japanese food
Japanese diet, rich in grains and vegetables has a positive impact on longevity.Getty Images

Eating according to Japanese diet guidelines could lower mortality rates and increase life expectancy, scientists claim.

In 2005, the Japanese government developed a guide aimed at educating people about healthy eating. It helps them to find the right balance in their diet, in terms of product variety and quantity. "The Japanese Food Guide Spinning top" promotes grain-based dishes, such as rice, bread and noodles as the most important category of food.

Vegetables come next, followed by fish and meat, with dairy products and fruits at the bottom of the list of all recommended products. Japanese citizens are also advised to drink a lot of tea and water.

According to the authors of this latest study, published in the BMJ, this balanced combination of foods explains the impressive longevity of the Japanese population. In 2015, average life expectancy reached 83.3 years old.

Fewer cerebrovascular diseases

The team of researchers, led by Kayo Kurotani at the National Centre for Global Health and Medicine in Tokyo, investigated the link between adherence to diet guidelines and mortality rates in the country.

They examined data taken directly from lifestyle questionnaires which had been completed by 36,624 men and 42,920 women aged between 45 and 75 years old. All of them were followed up for a duration of 15 years and none of them had a history of chronic liver diseases, heart conditions, stroke or cancer.

Participants adherence to the government's food guidelines was assessed based on their answers. The researchers observed that men and women who followed the advices more closely had a lower total mortality rate over 15 years, and consequently, a higher life expectancy. When they looked at cause-specific mortality, they found this reduction in total mortality was mainly due to low rates of cerebrovascular diseases.

"Our findings suggest that balanced consumption of energy, grains, vegetables, fruits, meat, fish, eggs, soy products, dairy products, and alcoholic beverages can contribute to longevity by decreasing the risk of death", the study's authors emphasise.

What are cerebrovascular diseases?

The term refers to four types of diseases. They include strokes, transient ischaemic attacks, vascular dementia and subarachnoid haemorrhage.

Strokes are the most well known, and occur when a vessel bursts, causing bleeding into the brain, or on the contrary, when there is insufficient blood flowing into the brain.

A subarachnoid haemorrhage is a type of stroke. In this particular case, blood leaks out of the vessels to the surface of the brain.

A transient ischaemic attack is also very similar in its symptoms to a stroke, at least temporarily. It corresponds to a temporary decrease in blood supply to one part of the brain.

Vascular dementia can happen as a result of a stroke, or when there are problems in blood circulation. It leads to a loss of cognitive abilities.