What is Natto?

What is Natto?

Ancient Japanese staple and supposed superfood, Natto gets a lot of hype for something that looks like beans swimming in slimy pond
scum. Fermenting soybeans using bacteria creates
something slimy and sticky, but also funky and savory — and, some people believe, based
on a growing body of evidence, pretty good for you. Natto is often eaten in Japan as a high-protein breakfast food. Just add some soy sauce, maybe a little mustard,
green onions or raw egg yolk and serve over rice — like we did here. It’s pungent, by which I do mean stinky, and is often compared to washed rind cheese in terms of its complex funkiness and in-your-face-ness. When I tried it, I got strong notes of both cheese and coffee — which don’t seem like they’d go well together. It’s an acquired taste, but I can see how
you’d go about acquiring it — it’s actually really interesting! In fermentation, you use microbes that grow
and actually kind of pre-digest your food to create new and interesting changes in the flavor, the smell, the mouthfeel and even nutritional content. But you only want specific, friendly microbes
setting up camp. You don’t want others in there that could
cause the food to spoil. To transform soybeans into natto, makers use
a particular strain of the bacterium B. subtilis, a common soil-dwelling bacterium with some neat
tricks up its sleeve. When B. subtilis are facing stress from their
environment, they have an escape plan— they can start forming dormant cells housed in
super-tough armor called spores. Spores aren’t really alive; they’re kind
of like seeds of a plant but they’re practically indestructible. They’re resistant to extreme temperatures,
corrosive chemicals, and even radiation. And they don’t need food or water. So you can cook your soybeans at temperatures
and pressures that would kill most other microbes that might be around. Then you introduce B. subtilis spores while
the soy beans are still hot, and those Bacillus spores are the only thing that can stand to be in
there. After that, your natto-to-be is held in hot,
humid conditions for about a day or so to allow the bacteria to settle in and get to work. Since no one else is home, B. subtilis spores
wake up and have no absolutely competition to eat the lovely beans. And the effect of its munching is to transform
the bland unfermented soybeans into…THIS. But why do the bacteria produce these gooey
strings? Turns out this slippery substance is what
microbiologists called a biofilm — a protective environment for the bacteria to live in, something
lots of bacteria make for themselves. This particular biofilm is made primarily of polyglutamate. The amino acid glutamate is responsible for
the flavor of savoriness — these strings shed glutamate molecules, which our tongues
perceive as umami. More umami flavor emerges in the Natto over
time as the biofilm produces more glutamate molecules. Protected by this biofilm, the bacteria go to town chowing down on the carbs & proteins of the beans. The fermentation of natto takes place above
pH 7 — it’s an alkaline-fermented food. A lot of other fermented foods are actually
acidic, which makes them taste sour. That’s probably why I went in expecting the natto
to taste like yogurt or something, but instead it had a more earthy, slightly bitter flavor that reminded me of coffee or truffles.. Like a lot of fermented foods, natto was likely
“discovered” by accident and turned out to be a good way to preserve soybeans. But it’s still best fresh, as opposed to
frozen. And since it will slowly keep fermenting in
your fridge, after a while, it can get pretty strong. There’s also a lot of buzz surrounding the
health benefits of natto. The label “superfood” is usually more hype
than substance, but scientists have taken an interest in natto and what it might do
for us. For example, natto is the most potent food
source of vitamin K2, a micronutrient that helps build bone by transporting calcium from
your bloodstream to your bones. And B. subtilis is found in healthy human
guts, so eating natto might have probiotic effects. Natto also contains nattokinase, an enzyme
made by B. subtilis, that’s been shown both in the lab and in humans to have potentially
useful effects as a blood thinner and therefore in fighting heart disease. It supposedly works by breaking down blood
clots, so they can’t get stuck in your arteries and cause a heart attack or stroke. Human trials are still ongoing into the effects
of nattokinase, in heart disease as well as things like Alzheimer’s. We definitely don’t know everything about
nattokinase yet, like how or whether it’s actually absorbed by the body, and whether
it might interfere with other drugs. But doctors are keeping an eye on this one. That said, natto doesn’t have to be a health food to be worth eating. You can just enjoy the slimy funkiness. Which I sort a did. Let’s be real. I’ll give it another shot sometime. We want to give a huge shoutout and thanks to Ann Yonetani of NYrture Foods. Who, when we reached out about potentially fact-checking an episode, was so thrilled she sent us a bunch of free natto and Instagram resources and images and all kinds of great stuff! Thanks so much Ann. Thanks for watching and thank you Paul Smith and Chelsea Conlin for asking about natto. Drop your food chemistry questions in the comments. We love these ideas so we’ll see if we can take them on. Remember to subscribe, share, and hit the bell to get notified so we can waltz into your feed with a brand new funky food stuff every week.


  1. It's fucking DISGUSTING. Also, some trivia: if you're jailed in Japan, make sure you love this shit, because you'll be getting it three times a day, with each meal. Looks like torture, but in actuality it's because jails are forced by law to provide with a minimum daily amount of protein to their inmates lest they starve and natto is the cheapest protein in Japan.

  2. I love natto!
    I usually buy it frozen, and let each individual serving thaw out a day before i intend to have a nice washoku breakfast 🙂
    Though usually i prefer umeboshi with my rice instead of natto, but only because I'm utterly obsessed with them. Usually lunch is umeboshi too, in a nice onigiri lol

  3. So, let's go over fermentation, and let things kinda spoil a little thing: how about those cheeses complete with worms, like our Italian Cazu Marzu (or some other, as they call here, formaggi di fossa )?

  4. Cotton (cellulose) is dyed in basic solution, but wool (protein) is dyed in acidic solution. I would really love to know more about the chemistry of why. Thanks!

  5. Do a video on Olestra. Particularly Hydrogenated Olestra. Olestra can cause loose stool in large amounts but hydrogenated Olestra prevents this. 2 bad things come together to make a good thing.

  6. They're not mixing that natto up enough before eating it lol, it's probably so bitter. The more you whip up the film, the less funky the taste is. I couldn't even stomach the stuff until I saw how my girlfriend ate it, now I eat it with soy sauce alone and love it!

  7. I LOVE natto! Acquired taste, strong, and weird texture, but once you get it’s appeal, you end up loving it. Best to get it with rice first. Nice to see it featured here. 🙂

  8. I tried it today and for me,it was not that good.Maybe I was eating it wrong but I added the spicy mustard in and mixed it..when I tried it ,it was bitter and didn’t really taste like anything.It also smelled like coffee. Maybe one day…I’ll try it again..😅

  9. I live in Asia, outside of Japan, but we get relatively fresh natto. It does indeed smell like coffee, and has the mouth feel of stinky gooey cheese, but it tastes pretty mild, even kinda bland without seasoning. It also adds umami-ness to your meal. Personally, I love it.

  10. Great video! We tried Natto for the first time when we were in Japan and also made a video about it on our channel. We didn't like it at all 🙁 I don't think we will try it again haha.

  11. At 850 mcg of Vitamin K Natto is 1000% of the recommended daily dosage of Vitamin K. Excess Vitamin K can cause heart blockages and strokes. Vitamin K is a clotting agent and Natto is the leader of foods high in Vitamin K. I'm wondering which scientist over looked this and decided Natto was healthy?

  12. K, nobody going to point out how annoying she keeps dipping her chopsticks back into the jar? Just keeps dipping and dipping, that just seems disgusting to me and rude.

  13. Natto = the stuff that the aliens put on their walls?! I have seen those Alien movies with face huggers and acid for blood! Beware of Natto!!!!

  14. I love how like one third of this video is just shots of the speaker mixing the stuff around with chopsticks. Like, that's ASMR material right there.

  15. I like the natto I get from the Japanse food store her in ohio
    a… strangely high japanese population for a store that was here before Honda…
    but yay natto and ichiban noodles!
    and some tenticles

  16. Good information, but you need to learn how to wind your chopsticks in the air to break the natto strands. (It's a practice of any regular natto eater.) Also, Ann Yonetani rocks. I saw a video about her recently — just an incredibly intelligent and nice woman and she produces a superb product.

  17. I've been successfully taking Nattokinase (caps. 100mg/day) for the last 5years as an alternative to Xarelto (blood thinner) recommended by my heart specialist because I suffer from A-fib (atrial fibrillation ) and the risk of a blood clot is very high.

    I have had A-fib for some 35 years and never taken any blood thinner!. My understanding is that no blood clot can form with Nattokinase present in the blood stream and, if a clot is present, it will be dissolved in a matter of hours by the arrival of Nattokinase in the blood. 35 years of experience seems to confirm this view.

    Ted Bradley, Geneva. Switzerland

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