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Why You Would Want to Eat Fermented Beans and How to Eat Them; Natto, a Trendy Superfood In Japan

Kiyomi is a former Canadian pharmacist who is now living in Japan, where she enjoys being immersed in her Japanese roots.

In the West, superfoods such as avocados, kale, and quinoa have become quite popular, and although avocados have somewhat found their way into the Japanese diet, kale and quinoa salads are not so common. In Japan, the recently trendy superfood is definitely not new; it has been eaten it for hundreds of years, however only now are the health benefits understood more than ever, and the popularity has skyrocketed. It’s called natto, or fermented soy beans. Essentially soy beans are soaked in water before they are cooked by simmering, mixed with a bacteria known as natto-kin and allowed to ferment for a couple of days. The smell and slimy texture perhaps makes it hard to get used to, but I’ll go into how to eat it later. First, the health benefits; although just a soy bean, both its original nutrients, and those created through the fermentation process, become a lot easier for the body to absorb by the time the end product is finished . If you already know the benefits of these nutrients and are thinking of trying natto, skip to the next section on how to eat natto and how to make it taste wonderful, otherwise keep on reading!



The Health Benefits of Natto

1. Its Exclusive Enzyme Is Effective in Cardiovascular Health

This enzyme, found ONLY in natto, is called natto kinaze and resides in the sticky strings that give natto its slimy texture. After being consumed, it has shown to stop blood clots from forming and can be effective in helping to break up clots that have already formed. Thus, it plays a part in heart attack and stroke prevention.

2. It Keeps Your Blood Vessels From Hardening

As the bad cholesterol builds up on the insides of your arteries, the vessels become stiff and less flexible leading to high blood pressure and an increased chance of blood clots forming. It is believed that natto’s natural lecithin helps to clean up the bad cholesterol and maintains your blood vessel's pliability.

3. It Helps Combat Fatigue and Stress

This is also the work of natto’s natural lecithin in combination with the vitamin B1 contained in the soy beans which helps boost the mood and may help in keeping the mind alert.

4. It Has an Anti-Aging Effect

There seems to be mixed opinions of what component, whether it’s the natto kinaze, vitamin B, vitamin K, or isoflavones that are beneficial, but it is believed that whatever the combination is, eating natto leads to younger looking skin.

5. It Helps Build Stronger Bones

It takes a long time for bone to turnover, and somewhere in this process, if something doesn’t go smoothly, the bones will end up brittle or weak. We all know that calcium is essential for the building of bones, but osteocalcin is also essential in order for the calcium to be deposited. One thing that keeps the osteocalcin going is vitamin K2 which is found in abundance in natto. Eating just one standard size pack of natto provides enough of the recommended vitamin K2 intake for one day.

6. It Helps Keep You Regular

Being a fermented product, it is full of probiotics, important for keeping the bowels healthy and moving. In addition to that, the soy beans themselves are a good source of fibre which is also known to be a friend of the bowels.

7. It May Keep You From Catching a Cold

While on the topic of probiotics, in combination with improved gastrointestinal health, they also support the immune system, making it harder for unwanted bacteria to grow and invade your body.

8. It Can Be Part of a Healthy Weight Loss Plan

The high fibre (about 2.5g per serving), and high protein (about 6-7g per serving), will help keep you feeling full for a while after a meal that includes natto. With only around 80-90 calories (including the sauce) per individual packaged serving, that’s a pretty good ratio with fibre and protein. For those of you trying to limit carbs, one serving contains about 7g, which is the amount of carbs in 8 or 9 baby carrots, or half a slice of white bread, so it’s not an overload and can be considered ‘healthy’ carbs.

How To Eat Natto

So you’ve learned about all the great benefits of natto, and decide to give it a try either in Japan, or you’ve bought a package from your local Japanese/Asian import food store. You open up the package, take off the lid, and.. gross, you think to yourself "what is this smell? Is this stench normal?". Relax, it may smell like feet, but after I explain what to do with it, you just might find natto easy to eat. I, afterall, was that person who couldn’t stand the smell and taste of natto at first, and now I could eat it everyday!

1. Buying Natto

In Japan, natto is sold in packages of three (all for the low price of 1-2 usd). In import stores abroad, because of the relatively short expiry dates, they are usually found in the freezer section (don’t worry, the health benefits from the fermentation are NOT LOST with freezing!). There are so many brands of natto, and you may not have much choice if you buy it abroad, but make sure to buy the type that comes with the tare (sauce) to season it. Store it in your fridge or freezer and let it come to room temperature before eating (to get the most out of all the beneficial nutrients, room temperature seems to increase the amounts natto kinaze and lecithin).

Commonly found types of natto packaging

Commonly found types of natto packaging

2. Preparing Natto

First remove the top seal. There is often a thin film placed ontop of the beans as well to prevent drying, and to keep the packets of tare separate. To remove this, pinch the middle, so you don’t have to get your fingers slimy, and slowly lift. Using your other hand, use chopsticks to cut through and stretch the sticky strings by moving them in a quick circular motion several times; it’s almost as if you are trying to wind the strings around the tips of the chopsticks so that the strings become thinner and break. Eventually the strings will detach from the film which you can now throw away without having the strings float about and stick to everything.

It’s still not ready to eat because all the little beans are stuck to each other. They are smooth and slippery so the tare flavours will not stick to them. It’s time to mix, mix, mix; with your chopsticks, stir vigorously and you’ll find that it will become quite frothy and white (it should take about 50 quick stirs). This is what you want in order to hold all the umami in the seasoning. The other advantage is that it protects the important natto kinaze component which would otherwise just be broken down by acids in your stomach. And as a bonus, it is believed that these sticky fibres adhere to and help maintain mucous membranes important for prevention of seasonal allergies and colds or flus. Now add the mustard (if it’s the type that comes with it) and the sauce, mix again until thoroughly incorporated. Some people will add the sauce before stirring, but doing so may prevent as much froth from forming and as a result the natto kinaze may not work to its fullest.

The sauce is mixed in and the natto is ready to eat

The sauce is mixed in and the natto is ready to eat

3. Eating the Natto

Now, the part you’ve been waiting for; bring the container closer to your mouth, pick up some of the beans with your chopticks; because of the froth you’ve created, they shouldn’t fall between the spaces of your chopsticks and it should be rather easy to bring towards your mouth (if you’re having trouble, think of using the chopsticks like a scoop). Once you put the beans in your mouth, there will be strings attached to your chopsticks and to your lips, and even to the container. If you don’t cut the strings they’ll fly and stick to your face, your hands, maybe land on your clothes or the table, and it won’t look very nice to the people around you. Before you start reaching for other foods or putting your chopsticks down, make sure to cut the strings by the same circular motion explained when removing the film packaging. This will ensure a clean look when eating and prevent you from smelling like natto after. You can always try eating it with a spoon too, I find they cut through the stringy parts a lot easier.

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Another tip for making natto taste even better, is to eat it with a bowl of rice. You’ll often see the Japanese pouring their natto over warm rice, and sometimes eating it with a spoon to make it easier to get a whole mouthful at a time. The sweetness of the warm rice brings out the umami in the natto seasoning and mellows out the fermentation smell. It’s almost like comfort food for the Japanese. Just be careful here, because to get the full benefit of the natto kinaze, you must let your rice cool down slighlty. Anything more than 50 degrees celsius and the natto kinaze will start declining. A good idea is to fill your bowl with rice and then let it cool while you prepare your natto.

4. Try Some Natto Toppings

Eating just natto may get boring but there are many things you can top natto with to change the flavours a bit. If you still can’t get used to the taste of plain natto, you may want to try some of these toppings.

First, the toppings that boost the health benefits of natto: The allicin in green onion is said to be a good combination with natto kinaze in order to prevent the formation of blood clots. The lactotripeptides in cheese are said to keep the blood vessels flexible, enhancing the effect of the lecithin on cardiovascular health. Kimchi, also a fermented product is good with natto because the lactobacillus feeds off the soy beans. Not only does it improve gastrointestinal health, it’s one of the favorite toppings of natto for many Japanese.

Other common toppings that the Japanese use include mayonnaise, ra-yu (chili oil), ume-boshi (Japanese pickled plum), seaweed, grated daikon, katsuo-bushi (dried fish flakes), okra, canned tuna, shirasu (whitebait), hot pepper flakes, grated yamaimo (a type of potato), shiso (also called Japanese basil), and mentaiko (spicy cod roe). Then there are the condiments to mix in with the natto instead of the usual sauce and mustard; shiso-flavoured salad dressing, sesame seed oil and salt, regular soy sauce, mentsuyu (broth for noodles), ponzu or wasabi.

Another Japanese favourite topping the raw egg. It’s a nice combination because the flavour of the egg yolk is brought out and the pungent smell of natto is mellowed, but recently it has been found that the whites of the raw egg prevent the absorption of natto's biotin (good for the skin, nails and hair). I suppose if you’re living in the West, you wouldn’t use raw egg anyway, but if you do, just remember to use only the yolk, or use a runny egg (where the egg whites are cooked).

Natto is often topped with ingredients just as slimy as itself, such as grated yamaimo, nametake (a type of mushroom), or boiled okra. Since they are all rather slimy, they combine well when mixed with natto and the frothy/stringy parts seem to absorb sauces nicely as well.

I personally like to keep it simple, using the included sauce and mustard condiments, and topping my natto with small strips of seaweed (called kizami nori).

5. Try, Try Again and Don't Let the Smell be a Deterrent

I believe that natto is one of those flavours that gets better the more you eat it. The first time I tried natto, in my twenties, I thought it was horrible and I didn’t care much for the slimy texture. The smell was so bad that I was surprised the Japanese would eat something that smelled somewhat like sweaty feet. I challenged myself many times after that, thinking that maybe different brands had different smells and flavours. Nope. They all tasted and smelled similar. However, the more I ate it the more I noticed and became fond of the fermentation flavour. One time while eating natto, I realized that it had a similar flavour component to it as a yeasty piece of bread I had eaten shortly before that. Even beer and wine, when you think about it, has that characteristic fermentation flavour. Eventually I grew to like natto and can now eat it frequently without wanting to pinch my nose. If you like beer, wine and bread made with yeast, look for that fermention flavour and you may find you like natto too.

If you’ve only ever smelled natto, but couldn’t bring yourself to put it in your mouth, let me tell you that natto can smell pretty weird when other people besides yourself are eating it. I’m not sure the exact reason, but when I worked as a waitress in a restaurant that served natto, sometimes (for some odd reason, usually if the customer was male), I found the smell unbearable, even though I was totally ok with the smell when eating it myself.

6. If You're Scared of Trying it, Here Is Some Advice For Newbies

- Cook with it; I know I said that some of the heart health benefits are lost when heat is added, but natto is still packed with other great nutrients that aren't affected by cooking it. When heat is added, not only does the natto lose some of its sliminess, the pungentness also seems to dissipate, softening and becoming more like a freshly baked loaf of yeast bread. Adding it to miso soup, or stir-fries would be like adding regular cooked beans to your dish.

- Put it in the toaster oven; mix the natto with the accompanying condiments, add mayonnaise and spread over a thick piece of bread. Top with grated cheese and some chopped spring onions. Put it in the toaster oven and heat until the cheese is melted and beginning to brown. Voila! A delicious open-faced natto sandwich.

- Buy “mild” natto; Look for packages of natto that are made for people who find the smell a bit too much. There are some natto makers that have experimented with making natto that is more tolerable to people that can’t stand the regular variety. For example, the company Mizkan makes one called Niowa-Natto (a clever play on the word niowanai, or scentless).

Researchers in Japan say that natto is one of the many factors in the Japanese diet that is leading more and more people to live into their nineties and even making it past a hundred years old. Its health benefits continue to be studied and natto’s popularity is still soaring high. If you haven’t given it a try, or two, or three, I highly recommend you do! Once you get used it, there are so many ways to eat it that you won’t get tired of natto. It's an all-in-one affordable, healthy and delicious superfood!

This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.


Kiyomi Motomura (author) from Japan on February 09, 2019:

Yes, please do!

Liz Westwood from UK on February 09, 2019:

I had not heard of natto before. I will have to check the freezer section in the UK for it.

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