Nattokinase sounds like a name straight from a laboratory, and it actually came from an observation on a simple laboratory plate: in 1980 the Japanese researcher Hiroyuki Sumi noticed that an extract from natto broke down a layer of fibrin placed on it markedly faster than the other samples tested. In Zielona Góra we ferment soy into natto, and nattokinase is one of the enzymes that form during this process. I have gathered here what is known for certain: where the name came from, how nattokinase forms and what research shows.
⚠️ Are you taking anticoagulant medication (for example acenocoumarol or warfarin)? Natto is one of the richest natural sources of vitamin K, which may affect how these medicines work. Consult your diet and supplements with a doctor. See the important legal and medical information.
In short
- Nattokinase is an enzyme from the serine protease group, forming naturally during the fermentation of soy by the bacterium Bacillus subtilis natto.
- The name, combining “natto” and the “-kinase” suffix typical of enzymes, was given by Dr Hiroyuki Sumi, who isolated it in 1980 while studying fibrin breakdown on a laboratory plate.
- The best-described mechanism in the literature is the breakdown of fibrin under laboratory conditions (in vitro).
- In the European Union, nattokinase has no authorised health claim (Regulation (EC) 1924/2006), so we describe it from the perspective of its chemistry, history of discovery and what research shows.
- Fresh natto also contains vitamin K2 in the MK-7 form, protein, fibre and live cultures of fermentation bacteria.
Where the name came from and how nattokinase was discovered
The name nattokinase combines two elements: “natto”, the Japanese dish of fermented soy, and the suffix “-kinase”, typical of enzyme names. The discovery was made in 1980 by the Japanese researcher Hiroyuki Sumi. He was testing various substances for their ability to break down fibrin, the protein that builds blood clots, applying samples to a laboratory plate covered with a layer of fibrin. The natto extract broke it down noticeably faster than the other samples tested, which led Sumi to isolate the enzyme responsible and give it a name. The results were published seven years later, in 1987, in the journal Experientia (see Sources).
What nattokinase is and how it forms
Nattokinase is an enzyme from the serine protease group, that is a protein that breaks down other proteins. It forms naturally during the fermentation of cooked soy by the bacterium Bacillus subtilis natto, as a by-product of its metabolism. This is a description of the enzyme’s structure and origin, not a declaration of its action in the human body.
What research shows
Fibrin breakdown under laboratory conditions
The best-documented mechanism of nattokinase is its ability to break down fibrin in a test tube (in vitro). The literature also describes single studies in animal models and a few clinical studies in humans, which are methodologically varied.
What is not yet known
Results from test tubes and animal models do not automatically translate into an effect in humans after oral intake. Nattokinase is a large protein molecule, and the extent to which it retains activity after passing through the digestive system remains a matter of discussion in the literature. There is also a lack of large, independent clinical studies and of consensus on dosing, so we stay with a description of the enzyme’s structure and research results, rather than suggesting a specific effect after consumption.
How much nattokinase is in natto and in supplements
The amount of nattokinase in natto depends on the quality of the soy and on the temperature and duration of fermentation. Enzyme activity is described in FU units (fibrinolytic units), and in fresh natto it may range from a few hundred to a few thousand FU per gram, making this food one of the richer natural sources of this enzyme. Dietary supplements usually give a standardised activity, most commonly up to 2000 FU per capsule.
| Feature | Natto (food product) | Nattokinase supplement |
|---|---|---|
| Source | Fermented soy | Natto extract |
| Nattokinase content | Variable (a few hundred to a few thousand FU/g) | Standardised (e.g. up to 2000 FU per capsule) |
| Accompanying components | Vitamin K2, fibre, protein, live bacterial cultures | Usually no additional ingredients |
Natural natto provides a broader spectrum of components, while supplements focus on the enzyme itself. Some nattokinase supplements are deliberately free of vitamin K2 in order to avoid interactions with anticoagulant medicines.
Nattokinase and vitamin K2 MK-7
Fresh natto naturally contains both nattokinase and vitamin K2 in the MK-7 form, one of the richer dietary sources of this vitamin described in the literature. Vitamin K2 has two confirmed actions in the European Union (Regulation (EU) 432/2012): vitamin K contributes to normal blood clotting and vitamin K contributes to the maintenance of normal bones. These are the only wordings that may legally be used in communication about vitamin K, and they do not apply to nattokinase.
What else you will find in natto
| Component | Description |
|---|---|
| Nattokinase | Proteolytic enzyme forming during soy fermentation |
| Vitamin K2 MK-7 | Vitamin K contributes to normal blood clotting and to the maintenance of normal bones |
| Live bacterial cultures | Bacillus subtilis natto from the fermentation process |
| Plant protein | Complete profile of essential amino acids |
| Fibre | Natural component of soy beans |
Nattokinase in our natto and in capsules
Nattokinase forms naturally in all our natto during fermentation, and fresh natto says most about it, because it is soy right after fermentation, without further processing. We produce it in Zielona Góra from certified organic soy. For people looking for a standardised dose, we also have capsules with nattokinase.
See nattokinase 2000 FU capsules in our shop
Safety and precautions
Natto is a food that is safe for most healthy people. Because of its high vitamin K2 content, caution is advisable in several situations.
This applies in particular to people taking anticoagulant medicines (for example vitamin K antagonists such as warfarin or acenocoumarol), who should consult their doctor about consuming natto or nattokinase supplements. Caution is also recommended for patients after surgery or with clotting disorders, and for pregnant and breastfeeding women. Natto contains soy, so it is not intended for people with a soy allergy. Neither a dietary supplement nor any food product replaces a varied diet and a healthy lifestyle.
Summary
Nattokinase is a proteolytic enzyme that Dr Hiroyuki Sumi isolated and named in 1980, testing fibrin breakdown on a laboratory plate. It forms naturally during the fermentation of soy by Bacillus subtilis natto, together with vitamin K2 MK-7, protein and fibre. The available data come mainly from laboratory studies and a few clinical studies, which do not prove a causal relationship with a specific effect in humans. Natto is best treated as an element of a varied diet, not as a medicine.
Frequently asked questions about nattokinase
What is nattokinase?
It is a proteolytic enzyme from the serine protease group, forming during the fermentation of soy by the bacterium Bacillus subtilis natto. The name was given in 1980 by Hiroyuki Sumi, who was testing fibrin breakdown on a laboratory plate.
Does nattokinase have a confirmed action in the European Union?
No. Nattokinase has no authorised health claim in the European Union, so a reliable description is limited to its structure, history of discovery and what research shows, not to its action. The best-documented mechanism is the breakdown of fibrin under laboratory conditions (in vitro), which is not the same as a confirmed effect in humans.
Should nattokinase be taken in the morning or in the evening?
For natto as a food there is no recommended time of day; in Japan it is most often eaten in the morning. For supplements, follow the manufacturer’s instructions on the packaging, and if you take medicines consult a doctor.
How much nattokinase does a portion of natto contain?
Depending on the fermentation conditions, from a few hundred to a few thousand FU units per gram. Supplements usually give a standardised value, most commonly up to 2000 FU per capsule.
Does nattokinase thin the blood or dissolve clots?
Such breakdown of fibrin has been described only under laboratory (in vitro) conditions and does not automatically translate into an effect in humans after consumption. Nattokinase must not be attributed with the action of thinning the blood or dissolving clots.
Is nattokinase a medicine?
No. In the European Union it is a component of food or a dietary supplement, without the status of a medicinal product.
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. Caution is advised with anticoagulant medicines.
Does natto contain GMO?
Organic-certified natto is free of GMO and produced from soy from controlled crops.
Sources: Sumi H. et al., A novel fibrinolytic enzyme (nattokinase) in the vegetable cheese Natto, Experientia, 1987; Regulation (EC) No 1924/2006 and Regulation (EU) No 432/2012; EU Register of Nutrition and Health Claims (European Commission); EFSA (European Food Safety Authority); PubMed.
Legal and medical note. This article is educational and does not replace the advice of a doctor or pharmacist. The substances described here have no authorised health claims in the European Union (Regulation (EC) 1924/2006), and a food supplement is not a medicine and does not replace a varied diet. Full information is on the Legal and medical information page.
