Natto — An Ancient Japanese Soulfood
For over a thousand years, natto has been a staple food in Japan, long revered for its nutritive value and many health benefits. Today, natto remains a popular breakfast, snack or side dish, typically eaten with a bowl of rice.
Ubiquitous in Japan, natto is virtually unknown elsewhere. Natto is the food that Japanese grannies always tell their grandchildren to eat because it is “good for you”, and many recent scientific discoveries support this idea. Natto is fermented with a probiotic bacterial species (Bacillus subtilis) that promotes gastrointestinal health, and is also rich in nutrients shown to support cardiovascular (nattokinase) and bone (vitamin K2) health.
Natto is loved for its unique flavor and aroma — savory, umami-rich and pungent (quite similar to a deliciously stinky cheese). As a living food, natto is full of active probiotic bacteria, and as with other naturally fermented foods (e.g. wine, cheese, sauerkraut), the taste of natto evolves and intensifies with time. Freshly made natto has a milder flavor than natto that has been aged for a few weeks.
No description of natto would be complete without mentioning its uniquely sticky texture. Neba-neba is a Japanese word to describe the sticky, stringy, wispy film that coats natto beans. In Japan, the more “neba-neba“, the better the natto. In fact, standard practice is to vigorously stir natto before eating to increase neba-neba! This special gummy biofilm is where natto’s most healthful properties are found.
Do I Need To Stir My Natto?
Stirring up natto before eating is a Japanese custom that many believe also enhances natto’s healthful properties. In Japan, the question of how many times one must stir one’s natto inspires serious debate. Popular answers range from 30 to 300 times, however there is no scientific evidence that stirring enhances any of the health benefits of natto.
Whipping natto introduces air into the sticky biofilm that surrounds the beans, creating a light, foamy mouthfeel, a bit like a freshly made smoothie but stickier. So if you enjoy neba-neba, then stir away because stirring only enhances this quality! If you don’t, no need to do it.
Some people feel that stirring makes the natto taste better by bringing out more umami flavor. This is plausible because the sticky biofilm produced by the natto cultures is made of polymers of glutamic acid (the umami molecule). Vigorous agitation may release some of this glutamate, producing a deeper umami flavor experience.
How Do You Eat Natto?
The most traditional Japanese way of serving natto is simply on a bowl of rice. The vast majority of Japanese consume natto as a quotidien meal in this way, with only some variation of add-on ingredients or condiments used.
Be warned, it’s goopy! Eating natto this way without getting some of its spider web strings everywhere takes some practice. It may be easier to use a spoon than chopsticks.
Some people like to mix the whole thing together; others like to keep the rice/natto more separated. Scooping the rice and natto up in pieces of nori seaweed is another handy way to consume natto rice. Old school natto rice is the dominant recipe for serving natto in Japan, but some alternative regional natto traditions exist.
In some parts of Japan, natto is often consumed in hot miso soup (natto-jiru) instead of rice. Like natto, miso is a traditional fermented soybean product but the two certainly look and taste quite different. Three major differences are (1) miso is made with a very different fermentation process driven by a rice-associated fungus Aspergillus oryzae (2) miso is highly salted and (3) the soybeans are mashed into a paste rather than kept whole during miso production.
A typical Natto-Jiru is a hearty winter dish with origins in Yamagata prefecture in the northern mainland Japan. It consists of a basic miso soup base, loaded with hearty vegetables (e.g. daikon radish, potatoes, carrots, shitake mushrooms), tofu and natto. Traditionally, the natto would be chopped or mashed into a paste before adding into the soup, which would then be boiled for some time before serving.
To maximize preservation of natto’s probiotic and other functional components like nattokinase enzymes, avoid boiling or cooking natto extensively at high temperatures.
Adding natto to hot foods at the very end of cooking or just before serving will allow it to retain its full activity.
Miso soup is increasingly popular and easily available here in the US. Miso is an easy-to-use, savory soy-based broth base that can be used as a versatile alternative to meat or vegetable stock.
Here’s an easy modern spin on Natto-jiru, a simple Natto Miso Soup. The earthy, nutty flavor of the natto is complemented nicely by the umami-rich flavor of the miso broth. When diluted into soup the sticky texture of the natto becomes barely noticeable. This is a definite bonus for those still acquiring a liking for neba-neba!
If you’re using an instant miso soup mix, no recipe is needed! Simply dissolve the miso soup components in hot water according to instructions and mix in a tablespoon of fresh natto.
Natto Miso Soup Recipe
- On stovetop, bring ~1 cup of water /serving to boil, then reduce to simmer.
- Into the water, dissolve 1-2 heaping tbsp. of miso paste/ serving or to taste. In Japan, a fish dashi-based broth is used instead of water to start; a dilute vegetable or chicken stock can also be used to deepen the soup’s flavor, but I find that miso alone works fine, especially with the richness of the added natto.
- Typical fixings to add to a miso soup broth include diced tofu, wakame and scallions.
- Divide soup into individual serving bowls and add ~1-2 tbsp. of natto.
We know now that nurturing ourselves and our microbiomes with sustainably grown, whole fermented foods is a vital part of the recipe for optimal health. As probiotic foods go, natto health benefits are truly unique.
Ann Yonetani is the founder of NYrture Food, producers of New York Natto, a Japanese probiotic superfood made fresh in NYC. A microbiologist with life-long passions for both food and science, she worked for over 15 years as a biomedical research scientist before becoming a natto maker. For more recipes and ways to eat natto visit the Natto Recipes page at www.nyrture.com.