Nattokinase - what's behind the fibrin-splitting protein?

Diseases of the cardiovascular system are now almost part of everyday life. Almost one in two people will suffer a heart attack, stroke or embolism at some point in their lives. An unhealthy lifestyle or genetic predisposition can lead to arteriosclerosis (hardening of the arteries), which favours these diseases.
Once the diagnosis has been made, the cardiologist or GP will often prescribe blood-thinning or blood pressure-lowering tablets, which can even be vital! If side effects occur, people look for alternatives that may be of natural origin - and come across the keyword nattokinase.

We have summarised the most important points on this topic for you here.

What is nattokinase?

It was first described by a Japanese researcher in 1987, has enzymatic activity and belongs to the group of proteases. In its original form, it is extracted from the Japanese dish natto (fermented soya beans). However, the pure active ingredient can now also be produced using biotechnological processes. It is said to be able to dissolve thromboses, thin the blood or normalise high blood pressure [1]. Research is still being carried out into these fields of action, so the effect has not yet been conclusively confirmed.

What is natto?

Natto is a traditional Japanese dish made from soya beans that are fermented by the bacterial strain Bacillus subtilis. In Japan, it is consumed as a dish, but is also used in naturopathy as a traditional remedy for cardiovascular diseases [2] [3].

Natto is said to be one of the healthiest foods and one of the reasons for the longevity of the Japanese. It is very easy to digest, rich in proteins and vitamins, contains isoflavones and probiotic bacteria.

It's easy to get the idea of simply eating natto straight away. For Europeans, however, it tastes extremely unfamiliar, smells very strong and looks unappetising as it is slimy and stringy. For this reason, the processed version of the nattokinase capsules is preferred. In addition, it is otherwise not possible to dose the food precisely, as the amount of nattokinase in it can vary greatly depending on the degree of ripeness of the natto and is therefore not known exactly. Natto naturally contains vitamin K, but the vitamin K is then filtered out in the end product, as it is considered an antagonist to pharmaceutical blood thinners. It is therefore essential to consult your doctor if you have to take medical blood thinners on a daily or regular basis and would also like to supplement with nattokinase capsules.

What is nattokinase good for?

This enzyme consists of many hundreds of amino acids [4] and, strictly speaking, is not a kinase but a protease. It has strong fibrinolytic activity [5], which means it can thin blood and thus dissolve blood clots. Various studies are looking into the extent to which it can act as a blood thinner, lower blood pressure and prevent cardiovascular disease.

However, there are also observations that it can provoke an increased tendency to bleed [6] and brain haemorrhages.

Is nattokinase harmful or even dangerous?

It is possible that it can thin the blood too much and thus cause internal bleeding. However, these assumptions have not yet been substantiated or insufficiently substantiated by medical studies. So far, good tolerability and a low risk of side effects have been recognised. Nevertheless, it is clear that areas of application and the necessary dosage have not yet been conclusively proven!

In the event of a diagnosed illness, always first discuss with the treating therapists whether an additional intake of capsules with this active ingredient could be appropriate in the individual case. Depending on the case, it may also be possible to optimise the existing therapy by taking additional capsules.

How does nattokinase work?

Nattokinase has enzymatic activity and belongs to the group of proteases. This also includes plasmin and thrombin, both of which are involved in blood clotting. While thrombin causes the blood to clot, e.g. to close wounds by producing fibrin, it can also clot blood vessels, which in turn can lead to thromboses, strokes and heart attacks. Plasmin, on the other hand, ensures that blood clots and the fibrin they contain are dissolved again (fibrinolysis). If there is a healthy balance of these two substances in the body, there is no danger.

The effect is similar to that of fibrin and has clot-dissolving properties. However, it is also said to have an indirect blood thinning effect, as two active peptides are produced during metabolisation, which in turn activate the enzyme tissue-specific plasminogen activator with fibrinolytic properties.

Can nattokinase be taken instead of aspirin or other blood thinners?

Because of the possible undesirable side effects of pharmaceutical blood thinners, there may be a desire to use only natural nattokinase products for existing cardiovascular diseases and to discontinue the medication administered. This is strongly discouraged! There are currently no or only inadequate studies on the presumably sufficient daily intake in humans! Furthermore, these steps should never be taken without consulting your doctor, as this could even lead to life-threatening cardiovascular problems!

Nattokinase products are not medicines but food supplements that can be used as part of a holistic programme of preventive care. This also includes a healthy lifestyle, a varied diet, regular exercise and stress reduction.

How does nattokinase affect blood pressure?

High blood pressure can accelerate the development of arteriosclerosis and other cardiovascular problems. Researchers in America and Korea looked into this issue and found that nattokinase had a blood pressure-lowering effect [7] [8]. Furthermore, researchers in Korea found that the enzyme also had a positive effect by reducing the activity of renin. Renin is a hormone-like enzyme from the kidneys that raises blood pressure.

As nattokinase is not currently authorised as a medicinal product, it is legally classified as a food, which means that the study situation is still inadequate. However, this situation appears to be improving, as the portal www.clinicaltrials.com reports. According to this, a study with 240 test subjects [9] is currently underway, the results of which could be very interesting.

Why nattokinase without vitamin K? Natto, a food made from fermented soya beans, naturally contains a lot of vitamin K, which is important for blood clotting. Many manufacturers of food supplements remove vitamin K from the contents of their capsules or tablets in order to focus on the main effect of blood thinning. It is therefore recommended to ensure that vitamin K has been removed from the capsules or tablets.

What are the interactions and side effects of nattokinase?

So far, the enzyme does not appear to have any significant side effects.

However, it does interact with other blood thinners!

Many studies have shown that the enzyme has an effect on blood clots and blood pressure. In one research project, scientists were able to demonstrate increased fibrinolysis and blood clotting inhibition in the blood just a few hours after administering 2,000 FU [10]. Unfortunately, this was also a study with a small group of test subjects, meaning that these results cannot yet be generalised.

However, capsules or tablets containing the enzyme from the soya bean are considered to be toxicologically safe [11]. However, it is risky if the enzyme is taken independently and without a doctor's instructions instead of prescribed blood-thinning medication, as the individual dose cannot be assessed independently! The product must also not be taken in addition to medications such as aspirin or other blood thinners without consulting your doctor!

Please always consult a doctor to avoid the risk of side effects!

How much Nattokinase per day?

The effect of Nattokinase capsules and tablets is measured in FU (fibrinolytic unit). This provides an indication of the effectiveness of the dietary supplement. In fact, it is the quality of the product and not the quantity that plays a role here. If the enzyme is inactive, no effect can be determined even with a large quantity. In this case, the quantity of FUs would tend towards zero.

According to previous studies, the intake of 2,000 FUs appears to be highly effective, which is why many manufacturers of dietary supplements offer this unit in their capsules and tablets. For example, in one study, a single dose of 2,000 FUs was sufficient to measure the enzyme in the blood [12] or to determine the effect on blood clotting [9].

The individual amount of FUs should only be determined in consultation with the treating doctor and checked regularly so that the appropriate dosage can be defined together. As every body reacts differently, it is not possible to give a generalised answer to this question. Some patients need to take 2,000 units, depending on the severity of their condition, while others have been recommended to take up to 6,000 units at a time over a longer period of time. If you have problems with your blood pressure or your doctor has diagnosed blood clots, he or she has probably already recommended that you take daily medication. If you would like to take the enzymes as capsules or tablets as an alternative or supplement, be sure to discuss this together!

What does nattokinase contain?

In addition to natto, the Japanese dish made from fermented soya beans, there are only a few other foods that are also considered to be a source of fibrinolytic enzymes. Cheonggukjang, a Korean soya bean paste, douchi (salted and fermented black soya beans) and tempeh, a fermented soya product from Indonesia, are also mentioned in this context.

Sources

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6043915/
[2] https://pubmed.ncbi.nlm. nih.gov/28264497/
[3] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5372539/
[4] https://www.ncbi.nlm.nih.gov/protein/AHD46009.1
[5] https://pubmed.ncbi.nlm.nih.gov/2123064/
[6] https://www.arznei-telegramm.de/html/2011_02/1102023_02.html
[7] https://pubmed.ncbi.nlm.nih. gov/27785095/
[8] https://pubmed.ncbi.nlm.nih.gov/18971533/
[9] https://clinicaltrials. gov/ct2/show/NCT02080520
[10] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4479826/
[11] https://pubmed.ncbi.nlm.nih.gov/26740078/
[12] https://pubmed.ncbi.nlm.nih.gov/23709455/