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Natto: why this Japanese classic deserves a place on your menu

What is natto?

Natto (なっとう), a traditional and popular ingredient in Japanese cooking, has been on the menu for over a thousand years. The Japanese have natto with their rice for breakfast, combine it with soy sauce and mustard for the perfect side dish and use it in their miso soup.

Natto is made from unpeeled soya beans. The beans are washed, steeped and boiled, and a probiotic bacteria (Bacillus subtilis natto) is added to kick-start the fermentation process. Fermentation usually takes about 24 hours. This process makes the active ingredients in the bean easier to absorb and releases health promoting enzymes, vitamins and minerals. It also splits the proteins into short chain amino acids, which are easier for the body to digest and absorb. Good news for vegetarians and vegans who would like a pure and ultra healthy protein which is easily absorbed.


But there is no escaping natto's texture and odour. It has a very cheesy smell, and its gooey texture makes it a lot like chia pudding, or even oyster. But like any strong cheese, and even the stickiest chia pudding, natto is a taste you will eventually acquire. And it's well worth the effort ...

Why is natto so healthy?

 The old saying, "unknown, unloved", pretty much encapsulates the Western attitude to natto. But more and more of us are learning to appreciate natto, and that's probably due to our growing awareness of the health benefits.

 Natto and vitamin K2

 The best known of these benefits is vitamin K2, which natto contains in its most active and easily absorbed variant: menaquinone-7.

There are three types of vitamin K: vitamin K1 (of plant origin), vitamin K2 (of bacterial origin) and water soluble vitamin K3 (produced through synthesis).
In people with healthy intestinal flora (which we don’t necessarily have) vitamin K2 is either manufactured by the intestinal bacteria or absorbed from food. Natto is an excellent food source in this respect: it contains over a 100 times more vitamin K2 than many cheeses. Good news again for vegans and vegetarians : natto is the only plant-based food which is rich in vitamin K2.
Why is this vitamin K2 so important to us? Well, to begin with, K2, or more particularly menaquinone-7, is essential to an optimal exchange of calcium. It helps prevent calcium deposits in the arteries, which in turn helps prevent high blood pressure, arterial stenosis (narrowing of the arteries) and atherosclerosis (arterial calcification). And secondly, vitamin K activates osteocalcin, an acid which fixes calcium in the bones, which in turn prevents osteoporosis, particularly when combined with vitamin D3 and calcium.


You may be thinking that vitamin K2 and a healthy calcium exchange are of greater benefit to the elderly. Nothing could be further from the truth! Children and adolescents need as much calcium as they can get for their rapidly growing bones. But there's yet another benefit for every one of us to enjoy: K2 prevents the build up of calcium in our arteries, which improves our blood circulation. Nutrients reach our organs through our oxygen-rich blood and waste products are more efficiently carried away. And the result? We feel a lot fitter.

 Natto as a probiotic

 As you have seen above, natto is a fermented product which owes its existence to the probiotic bacteria Bacillus subtilis natto. Natto is an excellent probiotic - a living microbiological food supplement. It invigorates the immune system, protects against stress, strengthens the intestinal flora and improves gastric and intestinal functioning.

 So there you have it. Why this Japanese giant deserves a place on your menu!