Sunday, August 23, 2020

Why Natto?

(obligatory natto "money shot")

My latest Instagram project is #19DaysOfNatto.

What is nattō? Why natto? And why 19 days?

UPDATE (2021-09-17): Natto extract, a Japanese fermented soybean food, directly inhibits viral infections including SARS-CoV-2 in vitro.

(Note that this study came out A YEAR AFTER I made this blog post. Just sayin'.)

Natto is a soy ferment made with a bacterial culture, Bacillus subtilis var. natto. It is famous—and infamous—for its sliminess. To some, natto is a delicacy; to others, a horror.

Natto, like other fermented foods, has its origin myths. One story is that a samurai, Minamoto no Yoshiie, had just finished cooking soybeans and putting them in straw sacks for his horses, when the enemy attacked! Because of this interruption, the soybeans remained in the straw sacks for days. Straw is rich in B. subtilis, so when the soybeans were finally removed from the sacks, they had become natto, and Minamoto and his companions ate them.

Whether or not you enjoy the experience of eating natto, there is no denying that it is exceptionally nutritious. I generally avoid using the term "superfood" because I think it's thrown around way too casually, but I do think it applies to natto.

Natto contains nattokinase and vitamin K2, substances that are unavailable (nattokinase) or much less available (vitamin K2) from other food sources. These are key to circulatory health, deterring blood clots and helping with calcium regulation.

Natto also contains more of "the usual" vitamins than its unfermented counterparts, since vitamins can be byproducts of the fermentation metabolism of microbes.

Soybeans are rich in minerals—but unfermented soy contains large amounts of phytic acid, which blocks the absorption of calcium, magnesium, and zinc. Fermentation neutralizes the phytic acid, making the minerals in natto more bioavailable than in tofu or soy milk, say.

Natto is also an exceptional source of soluble fiber. This fiber is evidenced by natto's slimy texture. The scientific consensus it that soluble fiber is beneficial to digestion and to serum cholesterol regulation. (Natto's slime, technically mucilage, consists of polar glycoproteins, which are carbohydrate and protein components combined in molecules a specific way. I've observed this natto mucilage to have a peculiar quality: the more you try to rinse it off with water, the slimier it seems to get. This sliminess is suggestive of its high capacity for absorbing water and its high content of soluble fiber. In theory it should rinse off with enough water. In practice, soap gets the job done more quickly.)


Some people are happy to eat natto in its sterotypical preparation: over rice, with mustard and soy sauce and maybe wasabi and green onion.

There are so many more possibilities.

Undertaking #19DaysOfNatto has forced me to think creatively about how to eat this amazing and sometimes intimidating food.

Why 19?

Our best defense against disease is health. Anything we can do to be healthier in general will help us fight off pathogens. Am I saying that natto prevents COVID-19? No. But I have every reason to believe that it can help us avoid catching the disease, and that if we do catch it, natto can help us recover more smoothly.

In early March, while people in the US were stockpiling toilet paper, the Japenese were stockpiling natto.

My money is on natto.

It's time for us to get over our cultural blennophobia and embrace ねばねば.

Appendix: Where to get natto

In approximate order of preference:

  1. Find a local natto producer and buy directly from them in person.
  2. Find a producer who sells online and buy directly from them.
  3. Find a local shop that sells natto and buy from them.
  4. Buy from Amazon (affiliate link). (But why not look on Amazon, find a manufacturer, and then contact them and ask about buying directly from them?)

(In any case, I'd highly recommend getting natto that is made from organic or non-GMO soy beans.)

And if you are feeling adventurous, grab a copy of my friends' fantastic book, Miso Tempeh, Natto & Other Tasty Ferments (affiliate link), by Kirsten and Christopher Shockey. Natto is not hard to make, and making it yourself has the usual benefits: you can make it exactly the way you like it; you can be certain of its ingredients; you can save money; and it's fun and satisfying!


teto said...

Thanks for sharing, very interesting!

Alex Lewin said...

Thanks Stefano!