CNN reveals a food that is a 'miracle drug' that helps people live to be 100 years old, and that Vietnamese people have been using for a long time.

Beans are a staple in the diets of people living in the five Blue Zones: Nicoya (Costa Rica); Loma Linda (California, USA); Okinawa Island (Japan); Sardinia (Italy); Ikaria (Greece) - where people live long and healthy lives.

According to longevity expert Dan Buettner, people who live to be 100 years old in the above areas all consider beans a part of their daily diet.

'I believe beans are a superfood that's good for your health , ' Buettner told Insider.

In the Blue Zone of Sardinia, Italy, people eat chickpeas and fava beans at least twice a day. These two beans are the main ingredients in the appetizers of the daily meals, which is also how Sardinians get the health benefits of beans, Buettner said.

Similarly, expert Buettner said the main food that helps prolong the life of people in Okinawa, Japan is soybeans such as natto or miso soup.

'Okinawa people eat tofu with every meal. Typically, breakfast will be miso soup with tofu cubes made from soybeans ,' says Buettner.

Japanese miso soup.

The reason why long-lived people like to eat beans

All types of beans are rich in nutrients including vitamins, minerals such as copper, iron, magnesium, potassium, folic acid, zinc; essential amino acid - lysine as well as lots of protein and fiber.

Additionally, each bean has its own unique nutritional profile, so it's best to eat a variety, says Buettner. For example, aduki beans have more fiber than many other beans, while fava beans are high in the antioxidant lutein. Black and red kidney beans are high in potassium, and green beans are high in magnesium.

'The fiber in beans helps keep your gut bacteria healthy, reduces inflammation, and boosts immunity,' says Buettner. ' However, very few people eat enough fiber . '

'Beans are also high in plant protein, which is healthier because it has more nutrients and fewer calories than animal protein , ' adds the expert.

In fact, when people combine beans with whole grains, they seem to get most of the amino acids that make up a complete protein, similar to the protein found in meat, says Buettner.

Studies show the health benefits of beans, says Buettner. The soluble fiber in beans can cut 'bad' cholesterol and help prevent type 2 diabetes by stabilizing blood sugar levels.

One study found that eating beans four times a week can reduce the risk of heart disease by 22%.

Another study found that eating about 20g of beans a day can extend life expectancy by about 8 years.

Beans may even aid weight loss. According to a review of studies, people who ate about 250 grams of beans every day for 6 weeks lost 0.34 kg more than those who did not eat beans.

Beans are nutritious and popular among the long-lived people of the Blue Zones.

Beans are good for your body and your wallet.

In addition to all these benefits, beans and their legume cousins ​​are also cheap to buy and can be grown at home in a variety of soil types, making them the perfect food to help economically disadvantaged people reap the benefits of longevity, says Buettner.

In Vietnam, dried beans are also sold at quite cheap prices. Beans are also one of the nutritious, convenient foods that also come with the benefit of prolonging life that Vietnamese people have used for a long time.