I'll be stalking this thread as I want to know the answer to this, too!

I asked the same question and got this info from another member here - Retired Navy

"Okay, here are some realistic concerns about some of the alternatives to coumadin. The only vitamin that has legitimedly been found to help prevent clots is Vitamin "E". This is based on Harvard Medical studies and even then, more has to be learned before a final conclusion is made.

The popular supplement which many folks turn to who don't want to take coumadin is Nattokinase, a Japanese soy supplement. There are some studies which show it may provide some benefit as a clot buster, however, these studies were funded by the Supplement Manufacturers who produce them and we not a Blind Trial. From my own perspective, I am not a physician, there is not enough legitimate evidence to show this stuff really works. There are a lot of U.S. physicians who sell the stuff on their website, this should be the first clue to run away fast."

Nattokinase has been a supplement mentioned on DVT forum website since 2001 when it was sold like AMWAY products through distributors. I had discussed the topic of Natto with several of the U.S. top specialists and each have said the same thing - there is no "real" scientific evidence to prove that the Nattokinase really works as stated. Some patient who had a recent DVT and took it claim their clot had dissolved a little. Problem is, your body naturally dissolves "some" of the clot on it's own. So was it Natto or your own body who dissolved the clot; the jury is still out on this one...

I contacted the FDA who doesn't get involved with supplments and vitamins "unless" the manufacture makes a claim that the product cures a condition (or if the supplement leads to illness or death). The FDA has released several letters to U.S. physicians who sell the products on-line, asking them to stop marketing the product as a "Clot Buster".

Nattokinase, even as marketed is not a anticoagulant. There are claims that it will dissolve clots (a clot buster), however, any trial showing proof was performed by the manufacture and was not a blind trial (they knew who was on it and who wasn't). Many of the physicians who recommend the product sell it on their websites.

In lieu of all that, there may be some mild benefit to the product, side affects and complications are not really known. Taking Vitamin E, which is backed by a trial held by Harvard Medical, has shown to benefit people who are not on Coumadin. Most of these patients are told to only take Aspirin as a preventative. For folks in this particular group, Vitamin E might be also beneficial. More research needs to be done before a final conclusion can be drawn.

I personally don't try to persuade folks not to trying a product, however, I do like to caution them to get your physician approval before proceeding. There is a study in Japan that does show a patient who took Natto along with his anticoagulant medication suffered from cerebral hemorrage directly related to Nattokinase.

Dr. Stephan Moll who is one of the top researchers here in the U.S. as far as blood clots and blood clot disorders has explained more information about Natto. Much of his reference material and questions came from me. Here is the link to the fvleiden.org website which discusses this:

http://fvleiden.org/ask/70.html

There isn't any patient out there who would like to get off coumadin more then me. I've been on it (on and off) since 1992. I am on it for life, or at least until the new breed of oral anticoagulants have enough research behind it to identify long-term side affects. If a supplement or vitamin really worked, I would be on it. In regards to Vitamin "E", it does work but is suggested for those folks who are not on Coumadin. If on Coumadin, it will raise your INR.

Take care and stay Health!

Regards,
Tom