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Nattokinase’s Clot-Busting Promises Sway Scientists Who Should Know Better

It comes from the slime of a fermented food and is thought to do wonders for the cardiovascular system, but its benefits may just be spin and hype

It has been called a “powerful all-natural supplement,” one that shows “exceptionally potent” clot-busting action. This same enthusiastic source even refers to it as a “miracle food.” No, this was not written by a naturopath on Facebook; it comes from a scientific paper, whose authors really ought to be more objective.

The “miracle food” in question is nattokinase. A Google search for this supplement returns the kind of vague claims their marketers are legally allowed to make: may thin the blood and help break up blood clots, supports cardiovascular health and normal blood flow, and may reduce blood pressure. You are not told that it has been shown to reduce blood pressure but simply that, unlike a pharmaceutical drug that has proved its mettle, this supplement may lower blood pressure.

Nattokinase is another example of how culture can sway researchers, who feel a certain patriotic pride in proving that a local custom holds the power to change global health. And in an era where anti-vaccine activists feel emboldened to yell “fire!” in a crowded theatre, nattokinase has also become an unproven solution to a non-existent problem.

From slimy beans to nature’s plumber

If you want to consume nattokinase the natural way, I hope you like slime. The interest in nattokinase began in the 1980s when a researcher by the name of Hiroyuki Sumi was studying a Japanese food called nattō (usually spelled without the accent in English). It has been described as vegetable cheese. The way to traditionally make natto is to first cook soybeans, then add to them a bacterium called Bacillus subtilis natto. The mixture is left to ferment at room temperature for at least a day. This results in the beans getting covered in a viscous film that is secreted by the bacteria. Inside this gooey substance is, among other things, an enzyme that was discovered by Sumi in 1987. He already knew that natto could dissolve a clump of proteins called fibrins, which are involved in blood clotting. That special activity to dissolve clots, termed fibrinolytic action, was caused, it turns out, by the enzyme Sumi had isolated from the natto. He called it nattokinase.

In retrospect, this name accidentally alludes to the fact that the nattokinase story would be filled with misleading claims. Kinases are a type of enzyme that help move phosphate groups around, a critical function in life forms. But nattokinase is not a kinase. It’s a protease, a type of enzyme that helps break proteins down into smaller parts. Sumi and his team knew it was a protease but, for some reason, they called it “nattokinase.”

Natto is not the only food that contains nattokinase. Similar dishes exist in other parts of Asia, like Korea, Indonesia, China, and the Philippines. Likewise, Bacillus subtilis natto is not the sole secretor of nattokinase, and ingredients like chickpeas or brown rice can be substituted for soybeans in order to trigger the release of nattokinase from bacterial fermentation. These days, the gene which codes for nattokinase inside the DNA of Bacillus subtilis has been isolated and the enzyme can be produced industrially. All the better to feed a market hungry for all-natural cures to cardiovascular disease.

A look at reviews on Amazon of nattokinase dietary supplements sure makes it sound like this Japanese export is performing miracles. One person’s husband stopped his low-dose aspirin after starting a course of nattokinase and feels much better. Someone else writes that it gives them “tons of energy” and helped them with sinus congestion. In the boldest comment I saw, a reviewer essentially described it as nature’s plumber: “the most powerful non-prescription artery cleaner ever discovered.”

The scientific research, however, when stripped of its spin, doesn’t quite stick the landing that keeps this hype plane aloft.

Spinning out of control

Not all studies are created equal and this dictum is especially relevant to the world of dietary supplements, where tiny, substandard studies are conducted and their milquetoast results are spun into hype to be fulfilled by future studies.

There hasn’t been that much research into nattokinase, with most being done in rats or in Petri dishes (often using much higher doses than are recommended for human consumption). Many of the clinical studies, involving actual human participants, lack rigour or their negative results are subject to spin by the authors. A 2015 paper boldly asserts in its title that a single dose of nattokinase helps with clot busting. The study was done in 12 men and all the changes seen were actually “within the normal range.” This is what we could call a creative interpretation of results.

Nattokinase is also said to help break down the plaques associated with Alzheimer’s disease… at least in laboratory glassware. Whether this can be reproduced inside the human body remains to be seen.

Meanwhile, a 2018 review article points out a strange inconsistency. A study published five years prior had found that the amount of nattokinase in the blood of someone who ingested it was at its greatest 13 hours after consumption. This should be when its clot-busting action is at its peak… except that a study measuring this specifically found that the peak was two to four hours after ingestion, not 13. Despite the fact that there are 284 different brands of nattokinase supplements being sold in the United States alone, we have very little data on just what happens to this enzyme when taken by mouth. Is it broken down by the acid in our stomach, as most ingested proteins are? If so, an enteric coating, which protects a pill from this acid until it reaches the intestine, may help. But can it then be absorbed into the blood through the intestinal wall? And is the nattokinase that is detected in the blood still fully functional? Exactly what happens to nattokinase as it travels through the body should be known before it is sold as a health supplement, but the lax regulations surrounding dietary supplements allow salespeople to put the shopping cart before the horse.

An appeal to nature and to national pride

Papers published on nattokinase often sound like thinly veiled marketing material, which can be explained in two ways. These studies are commonly funded by the makers of nattokinase supplements and the extent of their involvement with the paper is not always made clear. Moreover, the majority of the studies come from Asian countries, where natto or similar dishes are part of the traditional cuisine. As we have seen with acupuncture and the use of supplements based on saffron extracts, national pride can influence scientific rigour.

We won’t get good answers from inadequate studies and hype, which is why I was happy to read about the randomized clinical trial run by a team at the University of Southern California. Its 265 healthy participants were randomly assigned to receiving a nattokinase supplement or a placebo, not for a month or two, but for three years. At the end of the trial, the researchers found no difference between the two groups in terms of blood pressure, blood markers of cardiovascular disease, or ultrasound measurements of their carotid arteries. As the authors remark, their participants did not have cardiovascular disease, so it is still possible that nattokinase might help those people in particular. But with roughly a dozen human studies of nattokinase so far, most of dubious quality, this trial shoots to the top of the pile and does not inspire my confidence as to the effectiveness of nattokinase supplements.

Yet, reading comments from people who take these supplements, it is impossible to ignore the false narrative they have bought into: drugs are synthetic and bad, whereas supplements can do the same thing but without the side effects. A paper published in 2009 illustrates that this persistent idea can even affect scientists. Taiwanese researchers showed that nattokinase alone does not help people with abnormally high levels of lipids in their blood, but in combination with a thing called red yeast rice, there was an improvement. They argued that the two should be packaged together as a nutraceutical. The twist is that red yeast rice contains varying levels of lovastatin, one of the first statin medications to be approved for sale. No wonder it worked. But the appeal to nature is strong: many people want to treat their cardiovascular disease “the natural way,” so they turn to red yeast rice and to nattokinase.

“We actually have a lot of medications that can help treat, stabilize and, in many cases, reverse the process of atherosclerosis [meaning the presence of fatty plaques inside the arteries],” says Dr. Christopher Labos, a cardiologist and an associate with our Office. This was in response to the erroneous claim, found in a scientific paper, that these types of drugs are difficult to come by. Thus, nattokinase, which showed promise in Petri dishes, is said to be a miraculous anomaly. This is not true: the drugs are plentiful.

As for patients experiencing side effects from their anticoagulant or anti-platelet medication, Dr. Labos tells me there are many different medications in the same drug class. “Even in a rare situation where somebody had a bad reaction to one, you could always try them on another.”

But for some, the hype surrounding an all-natural, clot-busting supplement aligns perfectly with their pseudoscientific panic and their financial interests.

“Get back to that pre-COVID feeling”

For anti-vaccine influencers, the real harm during the pandemic came not from the virus but from the vaccine, with imagined stories about how vaccinated people were shedding the dreaded spike protein, which would kill people by turning their blood into a clotted mess. It should thus come as no surprise that these same influencers are now endorsing (and sometimes selling) nattokinase as the vaccine clot-buster du jour.

The FLCCC Alliance, co-founded by Drs. Paul Marik and Pierre Kory, claims nattokinase helps with the (fictitious) “spike-protein diseases.” Dr. Peter McCullough also endorses nattokinase for “spike detox.” The Wellness Company, for which McCullough is the Chief Scientific Officer, sells a nattokinase-containing Spike Support Formula, which is said to help you “get back to that pre-COVID feeling.” Its price tag? USD 65.99.

Meanwhile, David “Avocado” Wolfe, the eccentric conspiracy theorist who weaponized feel-good vibes on Facebook to attract a massive audience of customers for his natural health products, sells VeganZyme, which contains nattokinase. A section of his store is dedicated solely to products that allegedly neutralize the spike protein, a molecule apparently so toxic and difficult to get rid of, Wolfe sells no fewer than 28 different products to get the job done.

With all of this noise, hype, and misinformation out there, it’s no wonder the average consumer is confused. So, let’s be abundantly clear. Vaccinated people are not shedding the spike protein. The coronavirus which causes COVID-19 is not benign, and the COVID-19 vaccines are very safe. Nattokinase does seem to have interesting properties when tested in the laboratory, but it has yet to show clear benefits in humans, and the largest and longest clinical trial came up empty-handed on these promises. It is also still not clear what happens to nattokinase when taken by mouth. Nattokinase supplements, if properly manufactured, seem to be safe, although many researchers have pointed out the possibility (if nattokinase does work as promised) of a bleeding risk when combining it with anti-platelet or anti-coagulation medication.

A healthy diet helps reduce the risk of disease, yes, but we should always be skeptical when a single food is elevated to the rank of king of the clot-busters. And if you feel like interjecting that Hippocrates, the father of medicine, actually said to let food be thy medicine, you may want to check your sources. It is likely to be a misquotation.

Take-home message:
- Nattokinase is an enzyme secreted by bacteria when fermenting soybeans during the making of the traditional Japanese food known as natto
- Nattokinase dietary supplements are claimed to help prevent and treat cardiovascular disease, although the studies done so far are not rigorous enough to support this claim and we still do not know with certainty what happens to nattokinase in the human body when taken by mouth
- Anti-vaccine influencers are selling nattokinase supplements as a way to “detox” from the spike protein contained in the COVID-19 vaccines, which is simply not based on good science


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