• Natto appears to be a helper for healthy hearts. (Dilu)Source: Dilu
It's not the prettiest dish, but natto has some powerful health benefits.
Bonnie Bayley

30 Mar 2017 - 10:45 AM  UPDATED 30 Mar 2017 - 4:11 PM

When you think of Japanese cuisine, fresh, delicate flavours and intricately presented morsels spring to mind. Amidst all this loveliness, gooey, sticky and stinky fermented soybeans seem somewhat out of place. Called natto, this pungent dish is lesser known in Australia, but it lurks in the freezer section of Asian supermarkets, waiting for adventurous types to seek it out. Craig Anderson, star of My Japanese Diet (screening April 6 on SBS) is one such culinary maverick.

In fact, when SBS Food calls him to chat about the documentary, he’s just finished a bowl of natto on rice – a daily ritual since filming My Japanese Diet, which sees him swap his former diet of burgers, pizza and lollies for traditional Japanese food. “Natto is a food that divides Japan: half of them hate it and half like it,” says Anderson, who maintained his Japanese diet even after cameras stopped rolling. “People complain that natto smells like foot odour mixed with paint thinner, but when I eat it, it tastes like Dijon mustard over cannellini beans and it provides protein and carbs that keeps me going through the day,” he says.

Natto, a traditional food in Japan for thousands of years, is made by cooking fermented soybeans. It has a flavour that has been described as akin to fermented cheese. While some love the taste and the sticky-stringy texture, it's often served with condiments such as sliced green onions, wasabi or pickled ginger. Cooking, too, helps make it approachable (Japanese food writer Makiko Itoh, of popular blog JustBento, suggests using it in stir-fries or curries, or in her pan fried natto and potato cakes).

The health perks of natto

Natto may not sound that appealing if you aren't a fan of funky flavours, but the growing body of research supporting its health benefits certainly is. Dr Kevin Wang, associate professor of molecular biology ant Northeastern State University, US, is one of the leading researchers exploring nattokinase, an enzyme extracted from natto. “Nattokinase has the ability to get into the blood stream and can directly destroy blood clots, thin the blood and improve blood flow,” he says. “It cleans out the blood vessels, reducing the risk of hypertension and stroke and can also reduce the risk of heart attack.”

According to Wang (who takes nattokinase supplements twice daily), it may well serve as a natural, side-effect free alternative to pharmaceutical anticoagulants such as warfarin. If you’d prefer to try the food version rather than a supplement, you’ll still reap the benefits. “We did an experiment where we found even one natto bean can dissolve fibrin [a protein involved in blood clots],”  Wang tells SBS.

Next generation natto

As well as cardiovascular benefits, natto is a rich source of vitamin K2, which is important for bone health. In a 2012 Japanese study, scientists found that habitual intake of natto was associated with significantly higher bone mineral density, which they ascribed largely to the vitamin K content of natto.  Other research tracking the bone mineral density change of postmenopausal Japanese women over time discovered that those who consumed natto regularly were less likely to experience bone loss, and as such, may be better protected against osteoporosis.

In the near future we may not even need to cultivate a taste for natto or add yet another supplement to our overly crammed medicine cabinets. “My current research is trying to introduce nattokinase genes into vegetables such as tomato and cucumber, and I’m hoping people will be able to access this in the next three to five years and that the price will be similar to regular fruit and vegetables,” Dr Wang says. “I’ve also been engineering soybeans to produce more nattokinase, so we don’t have to have the fermented ones.”

Fermented foods in the Japanese diet

Natto isn’t the only fermented superfood in the Japanese diet. As Anderson discovered during his stay in Japan, the line-up of fermented foods that the Japanese enjoy ranges from pickled vegetables (tsukemono) as a side dish or seasoning, to pickled ginger on top of sushi, umeboshi plums, miso soup and soy sauce, which is made from fermented soy beans. “A traditional Japanese meal includes all these little bowls of things and there’s always a fermented product there,” he recalls. For Anderson, fermented Japanese foods are now a part of his regular diet. “When I make bento boxes to take to work for lunch, I put an umeboshi plum on top of the rice and I’ll often add pickled vegetables to my bowl of rice and natto at breakfast,” he says.

According to Nicole Dynan, accredited practising dietitian and spokesperson for the Dietitians Association of Australia, fermented foods are well worth incorporating. “They are considered probiotics because they contain live bacteria, and there is evidence that they are beneficial in the treatment of diarrhoea, IBS, inflammatory bowel disease and also just for protection against infection generally,” she says. “Fermentation can also increase some of the micronutrients in food, B vitamins particularly, and for some people it can make food more digestible.”

If you’re keen to branch out into Japanese fermented foods, sipping on miso soup, using pickled vegetables as a seasoning or trying natto is a great place to start. 

In My Japanese Diet, award-winning actor and comedian Craig Anderson sets out on a dieting experiment towards better health by eating nothing but traditional Japanese cooking for 12 weeks. Watch his journey to Japan, and his new healthy regime, on SBS on April 6 at 8.30, then on SBS On Demand

Lead image by Dilu via Wikimedia. Natto on rice by melanie_ko via Flickr. 

Fermented soy
Pork, sweet potato and miso soup (tonjiru)

This porky soup is a hearty winter dish that’s popular in Japan – you could make it using chunks of pork belly or small pieces of pork spare ribs cut through the bone, but you’d need to increase the cooking time accordingly. You could even use pieces of chicken thigh fillet; this is a highly adaptable recipe. For a meal in a hurry, you can’t beat using the frozen, thinly sliced pork belly you find in the freezer section of good Asian grocers. It’s brilliant in this dish.

Water spinach and fermented soy beans
Miso soup with tofu

If your experience of this famous Japanese soup has only been of the instant kind, this recipe will be a revelation – it touches your soul. It is made with fresh tofu and wakame seaweed, but other classic combinations are daikon and fried tofu, potato and wakame, clams and spring onions, and pumpkin and spinach. If using ingredients that need to be cooked (unlike the tofu and wakame, which just need to be heated through), you can cook them in the dashi (stock) before adding the miso.