Natto is a traditional Japanese food made from soybeans fermented with the microbe Bacillus subtilis. It is one of Japan’s most noteworthy health foods. Did you know the fermentation process generates high levels of vitamin K2?
Is Soy Bad For Me?
Lots of controversy surrounds the issue of soy in our diet. The rise of genetically modified soy adds to the problem. (93% of all soy in this country is genetically engineered.)
The issue with soy in its natural state is that it contains various anti-nutrients that present problems for the immune system.These anti-nutrients help protect the bean from the sun’s radiation and microbial invasion but work against the people interested in consuming soy.
Soy’s anti-nutrients
- Phytates: All beans contain phytates (or phytic acid). Soaking typically removes most of this, but soybeans are particularly stubborn in this regard. Fermentation offers an extra boost.
- Enzyme inhibitors: Enzymes digest our food. When enzyme inhibitors are present, enzymes can’t do their job. This leads to gas and bloating, as well as a host of other issues. Soaking usually solves this, but again the fermentation helps even more.
- Goitrogens: These substances potentially block the production of thyroid hormones. Many people avoid soy simple because of the goitrogens.
{It’s important to note that fermented soy does not take care of the goitrogen issue. Sugar separates from the goitrogens during fermentation so that goitrogens may be increased. The good news is that a healthy thyroid should handle this. Some suggest foods high in iodine to counter the goitrogen effect. Others suggest alternative beans like navy beans or black beans. Still others suggest we keep fermented soy consumption to a minimum. Certainly less may be more when it comes to fermented soy.
Vitamin K2 and Natto
Soy in forms such as tempeh, miso and natto are not only rich in protein but rich in the fat-soluble vitamin K2. Of the three, natto is the most abundant source. Vitamin K2 is closely connected with the health of our bones, teeth, and overall immune system.
Health benefits of vitamin K2.
- Protects against heart disease
- Helps ensure healthy skin
- Contributes to strong bones
- Promotes brain function
- Supports growth and development
- Fights against cancer
To learn more about the immune boosting properties of vitamin K2, I recommend the book, Vitamin K2 and the Calcium Paradox. Author Kate Reheaume-Bleue offers an excellent explanation of why calcium supplements are coming up short in the fight against osteoporosis and why adult women are in need of vitamin K2.
While vitamin K2 is a recent discovery, it’s important to note that researcher Dr. Weston Price became aware of its benefits while studying dental health and diet in the 1930’s. Dr. Price found that primitive people groups with the healthiest teeth consumed traditional foods rich in a mystery compound he termed Activator X. We now know it as vitamin K2. (For more on Dr. Price’s research see On the Trail of the Elusive X-factor: A Sixty-Two-Year-Old Mystery Finally Solved.)
Convinced about vitamin K2? Look what natto has to offer!
*The butter in this graph refers to standard butter rather than butter from cows raised on fast-growing grasses.* The egg yolk statistic does not reflect pastured chickens raised in the outdoors. In both cases, vitamin K2 levels would be higher, but not nearly as high as natto.
Want to add natto to your diet?
Store-bought natto. Most Asian markets carry natto in their frozen food section. The flavor packets contain numerous additives. These can easily be tossed. The natto in the styrofoam package typically has lots of strings, which indicates proper fermentation. It is not clear whether or not the soybeans have been genetically modified unless you purchase a brand like MegumiNATTO which offers a non-GMO version. Find out if megumiNATTO is sold in your area here.
Natto in supplement form. Vitamin K2 comes from two sources: animal and bacteria. The K2 found in, grass-fed meat, egg yolks, and butter is called menaquinone-4 or MK-4. If this appears on the label, it is likely synthetic. Vitamin K2 in bacterial form has a range of MK-5 through MK-10. MK-7 is the one found in natto, and the one you’ll typically see on supplement labels. Amazon offers these varieties of vitamin K2 supplements.
Homemade natto. Making Natto from scratch is not as hard as it may seem. One of the biggest benefits is quality control. There are some farms that offer organic, non-GMO soybeans:
Laura Soybeans
Bob’s Red Mill
Wheatgrass Kits.
I have been making my natto for several years and have found a method that works for me. I did not acquire the taste quickly. Once I did, I found myself craving it. I’ll typically have several spoonfuls daily along with a calcium supplement I make with dried eggshells. See more on the interplay between calcium and vitamin K2 in the article What You Need to Know About Vitamin K2, D, and Calcium.
See How to Make Natto for the recipe!
I also have found considerable benefit in applying natto to my face! My skin seems to soak up the vitamin K2 and other nutrients.
What is your experience with fermented soy? Have you tried natto?
I love putting natto in our fried rice. When I first learned about how great it was for you, I bought it and put it in our smoothies since I had read so many comments about it smelling and tasting nasty. But my family actually really enjoys it and I’ve been tempted to just stir that little (chemical-laden) mustard packet in and start eating it right then and there, but I’d like to stretch each package as much as I can, so into the fried rice it goes. At least I can still taste it more than when it’s in the smoothie! 🙂
ihave been making natto for a year now the smell has banished it from the house imake it with chic pease or black beans ,I stuggled to eat it until I found a solution, iget some kale,water cress chi seeds, any vegetable about a hand full, put into a blitz machine with a cup of water give it 3 seconds along with 4 tablespoons natto beans its a treat to drink and gives the vegetables some protein ,what can be more healthy than that .
Great suggestion, John. Can’t beat it, that’s for sure.
hey there 🙂
Many thanks for the interesting post 🙂 ! Do you think Natto -instead of using cooked soybeans or chick peas – could also be made from rice, sprouted buckwheat or sprouted chick peas ? (since it is the bacillus subtilis natto that makes it ‘natto-like’ and brings out the vitamin k2)
best regards,
Anne 🙂
I know that miso can be made from rice, but not sure how the natto would work with rice. As I understand it natto needs to be made with beans, but that’s a great question and worth looking into.
I make natto using a one pound bag of black beans. I use a single serving packet of commercial natto (approx 41 mg or 3 Tbls) as the starter. My natto turns out stringy every time, but how do I know exactly how much MK7 is in a single serving? The graph you provide that compares Vit K2 levels of different foods does not give serving sizes. How much natto contains 1103.40 of Vit K2?