According to the experts — many of them, anyway — natto is the perfect food for curing what ails most Americans. There’s a large body (pun!) of evidence suggesting that eating natto on a daily basis significantly reduces the risk of heart disease, stroke, and high blood pressure (all exacerbated or caused by excessive blood-clotting), as well as arthritis and rheumatism (caused by stiff or swollen internal tissues). It is bold to claim that natto can prevent so many ailments, and unless you dig a little deeper, it probably seems no more reliable than the claims made for any other health-food or supplement. But I think natto is different. The evidence is there, and it’s worth paying attention to, if only for a few minutes…
The specific details of how natto does its magic are still being sorted out in scientific inquiries, but it appears pretty safe for us to think of it as a natural dispersing agent inside your body; when things (especially certain proteins) start getting together and creating problematic little bundles of blood or tissue, natto helps them to relax and break apart again.
This property of natto appears to be due to the presence of a unique enzyme, called nattokinase, which was first identified by Dr. Hiroyuki Sumi in 1980. He was studying the thrombus-destroying power of a variety of conventional medicines at Chicago University, and put some natto in the Petri dish on a whim. (“Thrombus” is one of many technical names for a blood clot that blocks arterial flow, causing heart attacks, etc.). Anyway, the thrombus was completely dissolved with 18 hours, which was far less time than what was needed for any of the other medicines he was working with. So he was impressed. He went on to isolate nattokinase as the active agent in natto, and has since examined its significance extensively; he remains a pioneer in the field. (People in the industry are fond of referring to him as “Dr. Natto”). His studies are widely available in English online, but here’s a decent place to start if you’re interested in a little more depth: http://content.karger.com/ProdukteDB/produkte.asp?Doi=205051&Scope=archiv.
I’m not a biologist, chemist, or otherwise certified professional, but I have read a bit of what those folks have published, and it appears that there is one overwhelming component in the body’s formation of both blood clots and stiff internal tissues. It’s name is fibrin. Fibrin is a naturally occurring substance, created when two proteins — fibrinogen and thrombin — interact.
Fibrin is essential to many bodily functions, but when you’ve got too much of it, bad things start to happen. And (you guessed it) most Americans have too much of it. Nattokinase is an extremely effective fibrin-destroyer (fibrinolytic agent, its called), which is a large part of what makes it so good for you — think of the dissolving thrombus in the Petri dish — but before we can appreciate this point fully we should probably take a closer look at fibrin and its constituent components.
Here’s an interesting little story about fibrinogen: back in 1929, a few curious men working at the Rockefeller Institute removed the livers from a number of rabbits and observed that these (in technical terms, hepatectomized) bunnies ceased to produce fibrinogen. Wow! From that time on, the liver was acknowledged as the body’s sole source of fibrinogen. Though it’s unclear why exactly this was considered important at the time, subsequent studies have revealed fibrinogen to be an important ingredient in a wide spectrum of bodily functions…and have supported the supposition that your liver is its only source.
But fibrinogen still isn’t too exciting all by itself; once it comes into contact with thrombin, however, some interesting things start to happen. As far as I can tell, thrombin is pretty amazing stuff. It is basically an all-purpose glue for proteins, which – I’m sure you’ll be interested to know – has led to some sensational commercial applications.
Most notably, a Nebraska-based company has isolated thrombin from the blood of pigs and cows, named it Fibrimex, and figured out how to use it for creating all kinds of hybrid meat products like bacon-shrimp and bacon-salmon. They call the process “cold bonding,” and it’s basically a synthetic version of what goes on inside your body when fibrinogen and thrombin interact. (Rarely do we get such instructive visual analogues to internal biochemical processes). Fibrimex is billed as “a tool in innovative protein design [that] will change the way you think about meat.” Apparently they don’t realize how scary that sounds.
Anyway, both fibrinogen and thrombin are produced by the liver (via a complex cascade of reactions), and together they are vital to a number of your body’s daily functions. Namely, they help your blood to clot and various of your tissues to remain intact. Obviously, if your blood doesn’t clot you’ll bleed to death from even the tiniest of scratches, and if your tissues don’t remain intact neither will you. So fibrinogen + thrombin (= fibrin) is great. But again, only in the right amount.
When your liver isn’t happy (from processing too many toxins or fats, for example), it can start producing way more fibrin than you need, and you can start getting clots inside your arteries and/or stiff tissues, leading to heart attack and/or stroke, arthritis and/or rheumatism. Not fun. But depressingly common.
So now maybe we have a little better understanding of the importance of natto in our daily meals? Nattokinase — the key component in natto — is the strongest fibrinolytic enzyme out there. In acute situations (like right after a heart-attack), nattokinase seems to break fibrin apart at least as effectively as the enzymes used in any of the drugs currently prescribed by western doctors. (I’d probably get shot for writing that natto actually works better than those drugs — all I’m saying is that the enzyme nattokinase works more effectively than the enzymes those drugs employ — urokinase, originally isolated from human urine, for example).
But, as with most medicine-food, natto seems to work best when you take it little and often — as a preventative measure. (This is true partly because natto stimulates your body’s production of other fibrinolytic agents, and doesn’t work on nattokinase alone). It seems that when you eat natto on a regular basis, the acute disasters caused by clotting and stiffening are far less likely to appear. (For more details, you might start here: http://www.liebertonline.com/doi/abs/10.1089/107628002760091001).
Anyway, the Japanese Ministry of Health and Welfare has granted nattokinase the status of a medicine, and regularly recommends that Japanese citizens eat more natto. Though we can’t expect the FDA to follow suit any time soon, I’d rather not wait around until they figure it out…in the meantime, it seems like a safe bet to eat natto a few times a week, forget about the medicines, and go on enjoying life. That’s my plan, anyway.