Natto - and nattokinase - against heart disease

Natto is a soy food famous for being awful. But now, nattokinase, an enzyme extracted from this fermented soy, is gaining fame as a food supplement that can effectively fight heart disease.

Discovered in 1980 by Japanese researcher Dr Hiroyuki Sumi, the enzyme has powerful fibrinolytic activity, meaning it can prevent and reverse blood clots.

Dr Hiroyuki Sumi showed that a drop of this substance, when placed over a blood clot in a laboratory dish, dissolves the clot completely within 18 hours. This makes it a powerful weapon against heart attack, stroke and senility. Dr Hiroyuki Sumi studied over 200 foods and found none to be as potent.

Some medical experts now recommend this enzyme over Aspirin for preventing heart attacks.

For decades, the medical establishment has been recommending "an Aspirin a day" to prevent heart attacks. But Aspirin is basically an anti-headache drug. It thins the blood but does not effectively prevent heart attacks. Moreoever, Aspirin comes with serious side effects, including stomach ulcers.

Sticky, slimy, smelly... yummy

What is natto? It is a fermented soy product that is stickly, slimy and smelly. Nattokinase is the substance that makes it sticky. There are many stories - mainly from foreigners living in Japan - about how horrible this stuff is. It does look - and smell - like rotten beans.

But then, those stories are no different from stories from foreigners in Southeast Asia talking about the durian, a smelly fruit, or in France talking about blue cheese. Each culture has its own version of an exotic, smelly food that puts foreigners off even though the locals enjoy. Recently, I bought some pickled herring (from the mini supermarket at Ikea) and my sister commented in a Chinese Teochew phrase that translates to "bad tasting until die!"

So there is nothing unusual about this "smelly bean". The Chinese eat a similar fermented soy bean and they also eat fermented "smelly tofu". The smell of this tofu is so strong that, if ever a restaurant in your neighbourhood starts serving the dish, you will surely know.

As with all exotic foods, however, there are people who love them. The Japanese have been enjoying natto for over a thousand years. Ancient Samurai are said to consume this fermented soybean daily even feed it to their horses to increase their strength.

Loving this smelly soy

I, too, enjoy it greatly, although I don't eat it often enough to enjoy its benefits. Guess I should eat it more often.

No doubt I had to acquire the taste. It was a macrobiotic teacher who recommended that I eat this fermented soy product. He noted that I have a weak digestive system - which is true, I have a lot of gas in my intestines - and he said it would strengthen my digestion.

But how to eat it? Like most people, I, too, initially found the smell and appearance replusive. "Easy," the macrobiotic teacher said. "Just add natto to miso soup." True enough, it did not taste that bad, And after eating it this way a few times, I began to enjoy eating this "smelly bean" on its own. Nowadays, I don't even find it smelly anymore.

Another way to enjoy this fermented soy is to eat it wish sushi. More authentic sushi bars would serve it. Sometimes, when I eat sushi with friends, I would order a roll or two for myself and then offer it to them. Most of them either like it or find it okay. It is not that smelly after all. And like the durian, it is more the smell that offends but the taste is acceptable to most people.

The more usual way to eat this fermented soy food is to mix it with:

• soy sauce
• mustard
• chopped scallions

The mixture does make the dish more delicious. For the adventurous and those already used to the sticky, slimy appearance, another way is to eat it with raw grated nagaimo (mountian yam, wai san in Chinese - another healthy food), thinly sliced okra (lady's fingers) and a raw egg. Every single ingredient in this dish is slimy! Whoa!

One dish that I miss is tofu stuffed with natto and then deep fried. It was absolutely delicious but I am not sure where the restaurant that serves this dish has moved to. I have yet to find it at other Japanese restauramts, but not that I have been searching hard either.

Probiotics or 'friendly bacteria'

The Japanese usually eat natto at breakfast and there is a good reason for this. The fermented bean is very rich in probiotics or friendly bacteria and it is good to take such bacteria on an empty stomach.

One gram of these fermented beans may contain between one million and one billion counts of active friendly bacteria. Only a small amount is eaten. The product is usually sold in small trays, each containing 40 or 50 grams and this is enough for one or two persons.

A single serving could therefore provide up to 50 billion counts of probiotics. In comparison, most brands of probiotics sold as health supplements contain only 1 billion to 2 billion bacteria counts per capsule - although I know of a brand that comes with 25 billion and 100 billion counts. More about that later.

Likewise, a serving of a cultured milk drink has only about 2 billion counts of friendly bacteria, if at all. Some years back, there was a newspaper report that many of these drinks were tested to contain hardly any live bacteria. Is it possible to make nattokinase from natto based on anything other than soybeans?

The friendly bacteria makes this fermented soy food a powerful immune booster and natural medicine against poisoning (by harmful bacteria). Traditionally, the Japanese ate it to prevent diseases like cholera, dysentery and thyphoid.

Nutrition and Vitamin K2

Like all fermented soy products, this smelly bean is rich in nutrition, offering good quality vegetable protein and a wealth of vitamins and minerals. Because of its good nutrition, it is often eaten by pregnant women in Japan to ensure a safe delivery and a healthy baby,

Natto is also rich in Vitamin K2, which is has similar anti-blood clotting properties as nattokinase. In addition, Vitamin K2 has been found to prevent osteoporosis, or calcium loss from bones. Most normal healthy people produce adquate amounts of Vitamin K2. But odler folks, as well as those who had taken antibiotics, may not produce enough. According to Dr Hiroyuki Sumi, just 10 grams of the fermented bean will meet an average person's daily requirement for Vitamin K2.

Cancer prevention

Among fermented soy products, miso is more well-known for its anti-cancer properties. However, natto has also been found to contain antioxidants that help prevent cancer and the research on this is on-going.

Overdose?

Is it possible to eat too much of this fermented soy food? Traditionally, it is eaten in small amounts and it may not be wise to eat too much of it. As with all things, if a little is good, more does not always mean better.

When I was attending a macrobiotic course at the Kushi Institute in 1994, I had a course mate, an American, who loved this smelly bean. His room was next to mine and one night, I heard him groaning away. The next morning, I asked if he was alright and what had happened. He replied: "I think I ate too much natto." He had eaten a whole bowl of it at dinner!

Click here for a Japanese pasta recipe with natto and seaweed sauce.

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