MIAMI: Affordable soybean products are said to sustain the longevity of Japanese people, but they aren’t being consumed as much as they used to be — particularly among younger people. With some saying Japanese food traditions are under threat, let’s step back and take a look at the power of soy.
Perhaps the most iconic soy product is tofu, which first arrived in Japan from China via Japanese missions dispatched there during the Tang dynasty (618-907). The soft food subsequently spread through Japan in the Muromachi period (1338-1573), ending up in the mouths of ordinary people by the Edo period (1603-1867).
Along with seafood, soy products were an important source of protein for people back then who didn’t eat much meat.
“The important foods for health are the three S’s,” said Yukio Yamori, director of Mukogawa Women’s University Institute for World Health Development and an emeritus professor at Kyoto University, who is known for scientific research into longevity. “We should be eating more soy and seafood while reducing our intake of salt.”
Yamori spent 20 years conducting field studies on longevity in 61 areas across 25 countries. He collected urine samples to study the kinds of nutrients in people’s diets.
The studies suggested that people lived longer, healthier lives in areas where soybeans and soy products were regularly eaten. In contrast, people from areas where soy products were not eaten tended to suffer from more vascular and heart diseases and had shorter life spans.
In China, people in Guiyang of Guizhou Province are famed for their long life spans. The highland city is populated with many ethnic minority people who consume lots of soy dishes like tofu and natto fermented soybeans, which might explain why the area is said to be the birthplace of soybean food culture.
“The soil in Guiyang isn’t suitable for rice cultivation,” Yamori said. “But out of the dozen or so areas I studied in China, the people of Guiyang were comparatively healthier and less obese with lower blood pressure.”
Yamori then ran experiments on genetically stroke-prone rats and found that the key to disease prevention was a soy-based diet.
“Rats that were fed a diet of soy proteins, dietary fiber and minerals suffered no strokes and lived longer and healthier,” Yamori said. “The experiment convinced me that even people with genes that put them at high risk of diseases can lead healthier lives by improving their diets.”