Natto is a traditional Japanese dish made from fermented soybeans, known for its characteristic taste and sticky texture. One of its most often discussed components is nattokinase, an enzyme that forms during fermentation. This article explains what natto is, how nattokinase is produced and what the scientific literature says about it. It is educational in nature and does not make any claims about treating or preventing disease.
🧭 In brief
- Nattokinase is a proteolytic enzyme that forms naturally during the fermentation of soy by the bacterium Bacillus subtilis natto.
- In the European Union, nattokinase has no authorised health claim (Regulation (EC) 1924/2006).
- Vitamin K2 MK-7, of which natto is a rich source, contributes to normal blood clotting and to the maintenance of normal bones (Regulation (EU) 432/2012).
- Natto also provides protein, fibre and live cultures of fermentation bacteria.
- Natto is a food, not a substitute for medicines.
What natto is and how nattokinase is produced
Natto forms as a result of the fermentation of cooked soybeans by the bacterium Bacillus subtilis natto. During this process the bacteria produce and release a range of compounds, including the enzyme nattokinase and vitamin K2 in the menaquinone MK-7 form. Fermentation also changes the profile of the product: characteristic sticky strands, an intense smell and an umami taste appear, and the soy becomes easier to digest. Natto is therefore a source of plant protein, fibre and live cultures of fermentation bacteria.
What nattokinase is
Nattokinase is an enzyme from the serine protease group, first described in 1987 by the Japanese researcher Hiroyuki Sumi. In laboratory studies (in vitro) its ability to break down fibrin, the protein that is the main structural component of blood clots, has been described. For this reason, in the scientific literature nattokinase is classified among fibrinolytic enzymes.
An important note: results obtained in a test tube and in animal models do not automatically translate into effects in humans after oral intake. The extent to which nattokinase retains activity after passing through the digestive system remains a matter of discussion in the literature. In the European Union, nattokinase has no authorised health claim, so it is not allowed to attribute specific health benefits to it in communication.
Vitamin K2 MK-7 from natto
The second characteristic component of natto is vitamin K2 in the MK-7 form. Natto is among the richest dietary sources of this form of vitamin K described in the literature. Unlike nattokinase, vitamin K has two health claims authorised in the EU:
- vitamin K contributes to normal blood clotting,
- vitamin K contributes to the maintenance of normal bones.
These are the only wordings about vitamin K that may legally be used in communication to the consumer (Regulation (EU) 432/2012). Any other statement about its action, even if based on research, is not authorised in the EU.
Why it is worth choosing organic, non-GMO natto
Organic and non-GMO products are made without synthetic pesticides and genetic modification. Choosing such food:
- supports sustainable agriculture,
- protects biodiversity,
- limits contact with residues of plant protection products.
The green leaf symbol on the packaging confirms the organic certification of the product.
What nutrients natto contains
| Component | Description |
|---|---|
| Nattokinase | Proteolytic enzyme that forms during fermentation (without an authorised EFSA claim) |
| Vitamin K2 MK-7 | Contributes to normal blood clotting and to the maintenance of normal bones |
| Live bacterial cultures | Bacillus subtilis natto from the fermentation process |
| Plant protein | Full profile of essential amino acids |
| Fibre | A natural component of soybeans |
Does natto have contraindications
Natto is a food that is safe for most people. However, because of its high vitamin K content, it is not advisable without consultation for people taking anticoagulant medicines from the vitamin K antagonist group (e.g. warfarin, acenocoumarol), because vitamin K affects the action of these medicines. Soy is also an allergen. If in doubt, it is worth consulting a doctor about including natto in the diet.
FAQ. Frequently asked questions
What is nattokinase?
It is a proteolytic enzyme that forms during the fermentation of soy by the bacterium Bacillus subtilis natto. In laboratory studies its ability to break down fibrin has been described. In the EU it has no authorised health claim.
Can natto be eaten every day?
For most healthy people, yes. In Japan natto is a regular part of the daily diet, most often in small portions.
Is natto the same as a nattokinase supplement?
No. Natto is a food containing many components (protein, vitamin K2, fibre, enzymes). A supplement is a concentrated extract focused on the enzyme itself.
Does vitamin K2 from natto help bones?
According to the authorised EU claim, vitamin K contributes to the maintenance of normal bones. This is the only allowed wording in this area.
Does natto contain GMO?
Organically certified natto is free of GMO and made from soy from controlled cultivation.
Sources: EFSA (European Food Safety Authority), EU Regulations 1924/2006 and 432/2012, PubMed.
This article was prepared by the Natto.pl team. It is educational in nature and does not replace medical consultation. Natto is a food, not a medicine. People taking anticoagulant medicines should consult their treating doctor about consuming products rich in vitamin K.
