Coumadin, Vitamin K, and a Plant-Based Diet

From the September 2004 edition of Dr. Fuhrman's Healthy Times:

I have been asked by multiple individuals to give a complete answer with guidelines for patients on Coumadin (Warfarin is the generic name) who have been told by their health professionals to avoid green vegetables because of the interaction between Coumadin and vitamin K.

This subject is of interest to me because I am a physician and author who advocates a green vegetable-rich diet for both weight loss and disease reversal and longevity. As a proponent of a diet rich in leafy greens, broccoli, and other foods rich in vitamin K, my dietary recommendations often contradict the advice of dietitians, nurses, and doctors who advise their patients taking Coumadin to avoid vitamin K-containing foods.

The reason health professionals recommend that their patients on Coumadin avoid vitamin K containing foods is because Coumadin produces its anticoagulation (blood thinning) effects by interfering with the activation of a vitamin K-dependent enzyme that is needed to build clotting factors.

When you ingest more vitamin K from green vegetables, you can decrease the effectiveness of Coumadin. A higher dose of the drug will then be required to maintain the recommended degree of blood thinning. The term “blood thinning” is a lay term that means a reduction in the natural ability of the body to form a blood clot.

The following definitions are important in order to understand this issue:

Coagulation: refers to the formation of blood clots formed by clotting factors and platelets, a normal body reaction when, for example, you cut yourself. Coumadin (Warfarin) is called an anticoagulant because it works against the formation of blood clots.

clots formed inside the blood vessels, typically to seal a defect in the vessel wall. These clots, when formed in the blood vessels that supply the heart with oxygen, cause heart attacks. Thrombus is singular; thrombi is plural.

a traveling clot, usually caused by a thrombus that breaks off and travels to a distal portion of the artery where it is narrower, occluding it, leading to a stroke, pulmonary infarction, or heart attack. A traveling thrombus is an embolus. Embolus is singular; emboli is plural.

In many cases, Coumadin is used as a preventive treatment to reduce the chance of forming emboli that could cause a stroke. Coumadin is most often prescribed for patients with atrial fibrillation, a common irregularity in the heart rate. When you have this irregular heartbeat, the turbulent flow of blood increases the likelihood of the formation of an embolus that can travel to the brain and cause a stroke. Coumadin therapy also is used by people who have experienced a serious blood clot.

Serious Side Effects
Since Coumadin is a drug given to prevent clots, the major side effect is bleeding. When you are taking Coumadin, you will not stop bleeding easily if you are cut. If you get in a car accident, you will more likely bleed to death. If you have a stomach ulcer or a broken blood vessel in your digestive tract while taking Coumadin, you can bleed to death.

The main problem with this medication is its very narrow therapeutic range—too much, and you can suffer from a major bleeding episode; too little, and it is ineffective at preventing embolic events. Patients have to be closely monitored with blood tests and their dose adjusted accordingly to make sure they are taking the correct amount.

According to current estimates, 70 percent of patients on Coumadin tend to stop taking the medicine because of frustration with blood tests, dosage changes, and side effects. While Coumadin monitoring is a medical necessity, many times the demands of heavy patient loads can make it very challenging for busy physicians to follow patients as closely as necessary.

Besides the risk of a major bleed, another serious but more infrequent complication of Coumadin therapy is drug-induced limb gangrene and skin necrosis. Other adverse reactions that occur infrequently include white blood cell diseases, hair loss, allergic reactions, diarrhea, dizziness, hepatitis and abnormal liver function, skin rash, headache, nausea and/or vomiting, and itching.

Physicians treat patients with Coumadin primarily to decrease the occurrence of thrombo embolism. They perceive that this risk has a greater clinical impact than the risk of Coumadin induced bleeding. However, only recently has the extent of the risks of bleeding been thoroughly investigated. A recent meta-analysis that pooled data from 33 separate studies examined the bleeding rates of patients who received at least three months of anticoagulation therapy. Major bleeding occurred at a rate of 7.22 per 100 patient-years, and fatal bleeding occurred at the rate of 1.3 per 100 patient-years.1 That means if 10 people were put on Coumadin therapy for ten years each, seven out of the ten would have suffered a bleeding event and one would have died from taking Coumadin.

Only for High-Risk Patients
Before 1990, Coumadin therapy for the prevention of stroke for those who had atrial fibrillation was limited to those who also had additional risk factors, such as rheumatic heart disease and prosthetic heart valves.

In recent years, however, hundreds of thousands of patients with atrial fibrillation, including those without significant accompanying risk factors, have been placed on Coumadin to decrease the risk of embolic stroke. Medical studies have shown that patients with atrial fibrillation, who also have other risk factors for strokes, did have a survival advantage and a reduced risk of strokes when Coumadin was prescribed. The results were considerably better than those in high-risk patients who only used aspirin, but not considerably better in patients who had only atrial fibrillation and no other serious risk factors.

Younger patients with atrial fibrillation and those without cardiac risk factors have not been demonstrated to have lived longer as a result of taking Coumadin. Aspirin does just as well in this low-risk group mainly because strokes are more infrequent.

The American College of Cardiology recommends aspirin, not Coumadin, for those patients with atrial fibrillation who have a relatively low risk for embolic stroke. That includes patients who do not have diabetes, advanced atherosclerosis, poorly controlled blood pressure, an enlarged heart, a recent embolic event, obesity, or who smoke. In other words, it is standard practice that treatment with Coumadin be guided by the risk of thromboembolic events and not be used for those patients at relatively low risk.

Eat more healthfully and stop taking Coumadin. The main problem with the studies that show that patients at risk of stroke benefit from anticoagulation with Coumadin is that they tested mostly high-risk patients on the typical disease-creating American diet, not low-risk patients on a vegetable-heavy, plant-based diet. As one’s diet changes to include more vegetation and less and less animal products and refined foods, one’s cholesterol drops, one’s blood pressure typically decreases, and one’s risk of a heart attack or embolic stroke plummets.

A high-nutrient, plant-based diet already has been demonstrated in medical studies to have a powerful effect at decreasing the risk of embolic stroke as well as heart attacks. In fact, in the Nurses Health Study a mere 5 servings per day of fruits and vegetables reduced risk of embolic stroke by 30 percent (and this is still a poor diet by my standards). 2 Another study looking at the consumption of greens, vegetables, and daily fruit consumption found a dramatic decrease in stroke incidence (approaching 50 percent) when they compared high and low fruit and vegetable consumption.3 My dietary recommendations, extremely low in salt and offering the equivalent of more than 10 servings per day of stroke-protecting produce, have been demonstrated to dramatically lower cholesterol and offer a much greater resistance to both strokes and heart attacks than Coumadin therapy. For people following my nutritional advice, the use of Coumadin becomes ill-advised. The use of this dietary intervention quickly drops people from a high-risk to a low-risk status. In most cases, Coumadin is no longer needed.

Most people on Coumadin would be much safer if they ate an ideal diet with lots of vitamin K containing greens; took an aspirin, EPA/DHA fatty acids, and LDL protect daily; and stopped taking the Coumadin. The risk of all causes of death would decrease precipitously. Eating right will not cause you to bleed to death. Instead, it can save your life.

Natural anticoagulants to consider instead of Coumadin are tomato juice, pomegranate juice, fish oil, vitamin E, horse chestnut seed extract, and ginkgo biloba.

Is Coumadin the Only Hope?
For those who absolutely must take Coumadin, because of a recent thrombotic event, the danger of not eating a healthful diet exceeds the risk of increasing the Coumadin dose slightly to accommodate the healthier diet. As long as the amount of greens you eat is consistent, your doctor can adjust your Coumadin dose to accommodate it.

For the patient who must stay on Coumadin, the diet must be consistent from day to day to avoid fluctuations in the effectiveness of the drug. To keep the vitamin K amount constant, it is sensible to eat one large raw salad a day and one serving of dark green vegetables such as asparagus and string beans, but leave out the dark green leafy vegetables, such as steamed kale, collards, and spinach. Adding some of those to a soup is okay, however. The goal is to keep your vitamin K level stable, so the amount of blood thinning does not swing into a danger zone. A dangerous level of blood thinning can occur if the dose of Coumadin is adjusted to a high vitamin K intake and then suddenly the patient does not eat many vitamin K-containing foods for a few days. In other words, the main goal is to eat the same amount of vitamin K-containing foods every day.

In summary, the evidence indicates that both Coumadin and aspirin are effective for prevention of emboli in patients with atrial fibrillation. Coumadin is more effective than aspirin in those very high-risk patients, but is associated with a higher rate of serious bleeding. The advice of the typical healthcare provider to severely limit vitamin K-containing foods does not consider the risk reduction that occurs from the dietary improvements. A diet high in processed foods and animal products, although low in vitamin K, will increase your risk of a heart attack and stroke. Instead, eat even more of those high-vitamin K foods and, if at all possible, get off the Coumadin.
1. Linkins LA, et al. Clinical impact of bleeding in patients taking oral anticoagulant therapy for venous thromboembolism. Ann Intern Med 2003:139:893-901.

2. Joshipura KJ, Ascherio A, Manson JE, et al. Fruit and vegetable intake in relation to risk of ischemic stroke. JAMA 1999;282(13):1233-9.

3. Sauvaget C, Nagano J, Allen N, Kodama K. Vegetable and fruit intake and stroke mortality in the Hiroshima/Nagasaki Life Span Study. Stroke 2003:34(10):2355-60.
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Comments (30) Read through and enter the discussion with the form at the end
Dale - August 19, 2007 8:29 PM

My friend has been on coumadin for a month. She is to avoid all geen leafy foods containing vitamin K. She would like to know if boston lettuce is on that list?

Tom - January 10, 2008 9:09 AM

My coumadin dosage is based, as you state on my consistantly eating a salad everyday. Some days, I just don't feel like a salad so I try to get my Vit. K from another source. The problem is not knowing if I'm getting a consistant amt of Vit. K when I do this. Why are the machines to test for the INR's so much more expensive than the machines that test diebetics?? I would love to be able to test myself more than once a month at the clinic since that test only really tells me if I've been doing things right in the last 24 hrs or so.

ahmad azza - January 13, 2008 2:39 AM

I need to know alist of foods that are high in vitamin k
thank you

Faye Traas - May 1, 2008 1:21 PM

I need to know alist of foods that are high in vitamin k
thank you

bryan - September 23, 2008 1:17 PM

I have Anti-thrombin III deficiency and suffered an unprovoked Pulmonary Embolism 4 years ago (I was 30). It's a hereditary disorder: my grandmother died at 39, grandmother 54 from pneumonia/pleuricy complications. My mother, two aunts, and at least one cousin have the deficiency (the rest are afraid to get tested). Needless to say I have been prescribed lifetime coumadin usage. I have been largely vegetarian for 7 years, fully vegan for 2 years and am now experimenting with a raw diet. It is true that you can have a consistant INR while eating only vegetables, as long as you avoid the heavy hitters: seaweed and kale, while limiting spinach to nights with a glass of wine ;). I also wanted to mention that one of my Aunts stopped taking coumadin several years ago and switched to an aspirin-method of blood thinning. After developing another DVT - despite being on Aspirin therapy - she had to return to a coumadin regimend. Good post. Thanks for being supportive of a healthy green diet for coumadin users.

Lisa - October 24, 2008 10:10 AM

Dr. Caldwell B. Esselstyn, Jr. M.D. and a Cardiologist, has written a book called "Prevent and Reverse Heart Disease".

He discovered through scientific research that an entirely plant based diet without ANY oil is the key to preventing, as well as reversing heart disease.

I have been following his guidelines since my 'event' occurred and my doctor is amazed at how quickly I have recovered.

He knows I do not want to have to use Coumadin indefinitely.

I am gratified to find another doctor that promotes eating healthy food versus being stuck on a 'life saving', yet dangerous pill for the rest of their lives.

"The doctor of the future will give no medication, but will interest his patients in the care of the human frame, diet and in the cause and prevention of disease."
- Thomas A Edison

R. - January 6, 2009 1:30 PM

Thank you for this very interesting and informative article, Dr. Fuhrman. Here's my question: all other aspects being equal, how many 325 mg. aspirin would have an anticoag effect equal to 4 mg. coumadin? Or are there actual studies on this I could be pointed to?
Many thanks!

Franklin Thompson - October 9, 2009 9:55 AM

What do you recommend for someone that has a mechanical heart valve and wants to get off of coumadin?

Ron DiNicola - November 30, 2009 5:15 PM

I am a vegan (6 years). I eat kale, broccoli, spinach - all the leafy greens. No meat. No dairy. No fish. I run regularly.

Yet, I have high blood pressure 150/90. My cholesterol is 210.

I feel fantastic. But, the doctors want me to take altace - a blood pressure medicine.

I am certainly confused (and scared) as to why my cholesterol and blood pressure are up.

Can anyone help me with some advice?

Ron DiNicola

Shaukat Halim - January 5, 2010 9:56 PM

All my life,my diet consisted mostly of green vegetables,fruits,fish and meat in moderation.
After the replacement of my mytral valve about 20 months,I have to take Coumadin for the rest of my life.I have done a lot of online research and bought a few books also,everyone,
have stated to keep the diet consistent.I do not understand,
how to keep the vitamin K in diet consistent,This means,I should take the same diet over and over again.

I am supposed to maintain a PT/INR level of 2.5 to 3.5,my dosage of Warfarin keeps on going high and the PT/INR level
keeps low.I started with a doasgae of 6mg,now I am on 9mg for three days and 6mg for four days of the week.

I am not taking any vegetables at all,with the fear that my
dosage of Warfarin will further go high.
I am looking to have some help to lower down the dosage of Warfarin.

Deborah Fulper - January 25, 2010 10:06 PM

My husband eats asparagus every day , he now takes coumandin, does he have to stop eating this vegetable?

gloria wise - February 19, 2010 4:41 PM

I had a back 23 hour back surgery 3 years. since then i have been on coumadin. then the clot went. since I have had a TEST called called pt inr. in goes up and down. I do not eat noe greens. this week my test was 1. my DR.said blood was lien.he changed my coumadin form 5mg for 5 days. then for 3 days 2and half what does lien mean. I go every 2 weeks for my pt and inr test, I am still confused. I do not have clots now .

Angie Banks - May 24, 2010 9:30 AM

My mother is on Coumadin and would like to get off....How long will it take for her to get off of this mediction?

I have read that a good diet of greens would do the same thing as Coumadin....

The risk of bleeding to death is to high to have her on this medication...

Thank you for this page...

Cathy B. S - June 29, 2010 12:43 PM

I have taken coumadin since 3/8/04 due to multiple pulmonary embolism in both lungs. I recently had emergency surgery that was complicated by the coumadin. My surgeon is adamant that I come off coumadin since extensive blood work shows no genetic reason for the embolism or that I would be in danger of developing this condition again. My oncologist insists that I stay on coumadin for life due to the initial onset of the embolism being so extensive. My surgeon advised that I have a filter implanted to prevent any future clots from reaching vital organs. I am at wits end as to what to do. I would like to obtain diet guidelines that would assist in the stopping of the coumadin and taking an asperin per day. Any suggestions?

Art Tuscher - August 6, 2010 9:09 AM

I was a real active guy until the onset of a deep vein thrombosis (possibly brought on by a trauma to my lower leg) in April of 09. I was treated with warfrin to regulate my INR level. Since then I have suffered from severe migraine, been in and out of many emergency rooms with severe chest pain (many times), tingling and numbness on the left side of my body. I've been seen by many doctors from three of the best medical institutions in the country. Through these exams it's been discovered that I have a PFO (patent foramen ovale) which is a small hole in the atrial wall of the heart. The PFO is small and I'm told 1 in 4 people have this condition.
I was taken off Warfarin in Feb of 10 and within a month developed a PE (pulmonary embolism).
I have been checked for just about everything you can imagine and am told that other than the clotting issue, I am very healthy and that I will need to be on Warfrin (which has little or no side effects ?) for the rest of my life. I am in the high risk category for stroke I guess.
I'm am 51 years old and until 1.5 years ago, in very good health. I dont smoke, drink, and WAS physically active. I feel like I've aged 20 years in that time. I'm desperate for suggestions. I'd like to get back to a normal active life.
Please forward a diet that is rich in fruit and vegtables that is compatible with this drug.

terry hughes - November 16, 2010 12:20 AM

Please help me find a way for my mom to lower her coumidin level. She has severe vericose veins from this drug and the more she has been on this the worse the veins problem is.I am very aware of coumidin and its uses none the less mom would rather try to use natural foods. Please give me suggestions. Thanks.

Lisa - January 1, 2011 8:53 PM

"Art Tuscher - August 6, 2010 9:09 AM-
I'm am 51 years old and until 1.5 years ago, in very good health. I dont smoke, drink, and WAS physically active. I feel like I've aged 20 years in that time. I'm desperate for suggestions. I'd like to get back to a normal active life.
Please forward a diet that is rich in fruit and vegtables that is compatible with this drug.

Eat all the fruit and vegetables you like and stop taking rat poison! I did.

I was taking Warfarin, getting tested monthly, watching my INR levels and not eating too many green vegetables, etc. but quit after I read that it causes strokes AND osteoporosis.

I also developed blood clots in my legs on two more occasions that had me on the couch with a heating pad to try and help the pain.

Since I was still getting blood clots, why should I risk developing two more serious ailments if the warfarin wasn't working anyway?

I kept looking and read some articles about natto being used to dissolve blood clots. I am using this instead and eating as many greens as I like. I feel good and hope to keep using it unless something better comes along. Just glad that I'm not going to have to worry about purposely inducing osteoporosis or stroke.

Please check out the links below and keep googling to find new ones you can add for others. I am not a doctor so please take my opinion for what its worth. That of a person looking for answers that heal or at least won't hurt.

Warfarin, the vitamin K killer
Hilary Butler
June 17, 2010

gina - January 31, 2011 11:41 AM

I am a 50 year old women . Due to a car accident, I now have to take warfarin. When I have my period, I have extreme pain. Without checking out side effects, I had taken Midol for the pain and had no problems except for heavy bleeding. I have recently read the Midol box and it states that one should not take Midol if on blood thinners. I was recently told by my OBGYN to take evening primrose. I googled tnis supplement and have read that this is not a good combination. What is true????!!!! I am in pain during my period, is it okay to take the Midol since I didn't seem to have problems before? Thanks!

DAN - March 5, 2011 11:40 AM

How does v leiden fit into this.

Denise - March 27, 2011 9:19 PM

I am a 55 year old woman, due to a pain on my left side a blood clot was found in my lung. I too am on this coumadin drug and am scared to death of bleeding out. I am told that I only have to take it for 6 months to a 1 year.
If being a vegetarian or vegan is what it takes, bring it on. How do I receive the information and daily info to get started.

Shannon C - May 5, 2011 10:45 PM

Help! I want to stop taking coumadin. Have been on it almost 3 months. Have A-Fib. I would love to drink Green Smoothies again. Have been taking NattoKinase for a few weeks.

Coumadin 2.5 to 5mg. The M.D. doesn't have enough time to even get INR levels back to me until after 3 or 4 days of testing. And my INR levels have been too 'low' .... this is like a nightmare. However I'm grateful to be alive and 'well'.

Have any of you stopped Coumadin 'cold turkey' and used natural blood thinners instead?? I'd even be open to taking aspirin. The problem is I don't know how to transition from Coumadin to natural products/aspirin. ;-

Lisa - July 24, 2011 2:01 PM

Hi everybody,

I last posted in Jan (Lisa - January 1, 2011 8:53 PM). I was taking Warfarin since 2008. Even though my INR levels were always stable, I continued to develop new clots in both legs and had heavy menstrual cycles.

I finally became fed up and stopped taking the Warfarin last year before the holidays after I discovered it cause osteoporosis.

I started using Natto, taking Vit D and magnesium and eating LOTS of green veg instead and have not had another 'incident' since!!! My menstrual cycle has also returned to normal as well. YEAH!!!

Here are a few more helpful articles that might be of help to those who are taking these meds and having problems. They discuss blood clots, Coumadin/Warfarin and alternatives!

Common blood thinner increases risk of bone fracture

Without This (Vit K2), Vitamin D May Actually Encourage Heart Disease

Antipsychotic drugs lead to blood clots
"New research out of the U.K. adds to the growing body of evidence highlighting the dangers of antipsychotic drugs. Data gathered from tens of thousands of patient records reveals that popular antipsychosis drugs like AstraZeneca's Seroquel, Eli Lilly's Zyprexa, Johnson & Johnson's Risperdal and Bristol-Myers Squibb's Abilify, can cause severe blood clots in patients."


Expensive screening for blood clots causing dangerous treatments

Maria - August 8, 2011 10:42 PM

I am a 57 year old woman, I was diagnosed w/Thrombocitopenia according to one Dr. and Phospholipid according to another Dr.(Apparently the two diagnosis are related) I was prescribed coumadin by the second doctor, besides coumadin i also take hydrochlorothiazide and was taking Clonidine for high blood pressure, until i had a temporary loss of memory. I did a research on the internet and found out that Clonidine can cause memory loss, blood clots, kidney desease etc...Since then, I stopped taking clonidine w/ my Docter's advise, started walking every morning, started eating a healthier diet. I would like to stop taking coumadin. Please give-me some advise

Debbie Hughes - September 25, 2011 11:47 AM

I have read all of the questions from folks on this site but do not see any responses. Are the responses being sent directly to the poster?

I'm new to this; taking Coumadin daily trying to attain a safe INR level after a recent 'event' with DVT and Pulmonary Embolism. I'm ok with taking the Coumadin for a while but am struggling with how to maintain a consistint level of Vitamin K intake. Is there any documentation to assist with what foods have vitamin K and how much? I'd like to also know if I can have romaine on a daily basis. I've seen conflicting articles which confuse the issue.

Dorothy - January 20, 2012 2:12 PM

Please...I need a list of food high in vitamin K. I am on warfarin. Thank you

Shannon - February 7, 2012 9:17 AM

I am a 36 yr old female who was hospitalized with 2 clots in the neck. I have a history of Ulcerative Colitis that results my going into hospital with getting a PICC Line and they believe thats the reason for the clots. I am extremely frusterated with Warfarin because the horrible side effects and them not getting my results stable with my count that I've been dealing with for months now.

Connie - February 7, 2012 5:24 PM

I am a 53 year old female and recently had a PE. I am taking coumadin 3mg and will be on this for 6 months. I am a vegan and am concerned that I am not getting enough iron in my diet since cutting back on leafy greens. My INR numbers are stable at 2.3. Should I take an iron suppliment?

Micheal - May 27, 2012 8:41 PM

I am a 56 year old male and been on warfarin since my event early February this year. I have been on twice weekly INR tests since then and my dosage varies between 4 and 6mg. Before my latest surgery I was told to stop eating Garlic. Does Garlic thin the blood and has anyone tried it instead of Warf.....

Patrick Threewit - August 29, 2012 10:58 PM

I was diagnosed with varicose veins in one ankle almost thirty years ago and after about ten years I self-diagnosed myself with peripheral artery disease. I finally got so I couln't walk, so I had Ca EDTA chelation therapy for a few months and could then hike a lot in the wilderness. Then, this summer I got preoccupied and slacked off on my regular hiking and also took several long trips in my car, with the last one having led to a 2 and 1/2 inch long blood clot in my thigh and a small one under my knee. I have been on Coumadin for 9 days now.
As a healthy 67 year old who has not been to a regular doctor in 19 years due, I think, to eating healthily and using herbs and natural supplements, I am not happy at all being on rat poison. This is my first clot, and although my doctor said, today, that I will be off the drug in 6 months, I have talked many people with family members having the same condition, who say that one you are on it Coumadin, you will be on it until you die.
So besides walking a mile a day and losing 40 pounds, I would like to know how to be sure I would be off the drug in 6 months. That is, what vegetables can I ask my doctor about using that will ensure good blood tests and certain stoppage in 6 months?

heart disease facts - June 1, 2013 10:59 PM

Hurrah, that's what I was exploring for, what a information! existing here at this web site, thanks admin of this site.

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