Singing the praises of soy


The telephone rang, and food-culture historian Hisao Nagayama, an advocate of the Japanese soy bean diet, excused himself from the interview and left his seat to take the call.

“Pardon me for the interruption, but it was one of my publishers,” said the smiling 71-year-old when he returned a few minutes later to the table at his home in Tokyo’s Nerima Ward. “He said my latest tofu book was selling well so now he wants me to write one on natto. Wow.”

A regular newspaper columnist on Japanese people’s diet and longevity, the cheerful, easy-going and notably energetic septuagenarian confessed he wasn’t this busy until a few years ago. Now, though, in addition to his regular schedule at home, and lecture and research tours both in Japan and abroad, he is faced with an upsurge in requests for him to write or give talks about soy bean products in particular.

“With society aging, I believe more Japanese are becoming concerned about living healthily, and are taking responsibility for that themselves. As a start, they’ve begun to look into soy bean products instead of meat as a source of protein,” he said of the recent trend. “And that, in turn, is making me busy. But I think it’s really a healthy move.”

Born as one of the seven children of a miso and natto manufacturer on the coast of Fukushima Prefecture, Nagayama, needless to say, was raised on a basic diet of miso soup, tofu, natto and fish. “I believe that the calcium-rich diet on which I grew up made me healthy and carefree,” said Nagayama with a laugh. Indeed, grow up he did — to what is a towering 176 cm, pretty tall for a Japanese man of his generation.

In addition to calcium, that simple Japanese diet is also rich in protein, lecithin, saponin and soy isoflavones — all of which are believed to be effective in maintaining a good physical condition. However, as Nagayama pointed out, all the scientific data now supporting the nutritional efficacy of soy beans is only confirming what he, and countless generations before, already knew by experience.

Feed for war horses

Soy beans are considered to have entered Japan from China by the third century. Nagayama explained that, with the later introduction of Buddhism, which promotes a vegetarian diet, soy beans replaced meat as a source of protein for monks. Thereafter, although the beans were processed into various forms of food and seasoning, he said they only began to be widely consumed by the population at large during the Edo Period (1603-1867). “Until then, soy beans were primarily an important feed for horses ridden by warriors. But when society became battle-free and peaceful during this period, people were able to eat more soy beans themselves,” he said. It was at that time, he said, that the Japanese became the most successful people in Asia at processing the bean into various forms of food.

Nagayama has long experience of visiting elderly Japanese people to seek the secret of their health and world-record longevity, and he is confident the answer lies in their diet — which is full of soy bean products. “People who live a long time say they like miso soup and tofu and have eaten them all their lives,” he said, adding that miso soup also often benefits from additional nutricious additives such as fish stock that delivers brain-stimulating docosahexaenoic acid.

Among the many and varied soy bean products, Nagayama concedes that natto is the only one that provokes strong reactions across the board — either for or against. But once you have overcome its peculiar smell and taste, Nagayama encourages people to eat it, as the process of fermenting soy beans to make natto adds considerable nutritional value. “I grew up being told that natto will make us smart and have a good memory,” he said.

Even today, Nagayama eats natto every day, and when he does, he uses a special pair of chopsticks he made himself from chestnut twigs. His natto chopsticks are thicker than most regular ones but, according to Nagayama, this helps to get more air into it when stirring it together with soy sauce and karashi mustard. The sticky threads that appear when the natto is mixed also contain nutritions that benefit the body, he said. “When you have fun eating, it gets more delicious, you know,” Nagayama said as he proudly waved in the air his huge hashi.

Generally, though, Nagayama believes that in view of the aging population and the ever-emerging nutritional facts, the consumption of soy-based foods will inevitably increase. “People will need to eat food with constituents that support their longevity and the maintenance of an active brain, and for that, things like isoflavones and lecithin are necessary,” he said.

Nagayama is also keen for the resource efficiency of the soybean plant to be recognized globally — and not just in terms of the balanced nutrition. “To produce a given weight of meat requires the animal to be given at least five to seven times that weight in soy bean feed, but it’s much more efficient to eat the beans directly. That simple fact alone could perhaps help in solving the global food shortage as the population of the planet continues to rise,” he said.

“I speculate that the 21st century will become the century of eating soy bean products,” the happy food historian said. “If people around the world recognized the benefits of soy beans, really, the world would be a peaceful whole — just like a soy bean.”