Blood Thinners and Greens: A Mix to Avoid?

12 September, 2016 , ,

You might have heard that if you take an anticoagulant (blood thinner), like Coumadin (warfarin), you should stop eating, or at least eat fewer, green vegetables, because they contain too much Vitamin K. But is this really the case?

Before getting right into the topic, let’s review some basics. Firstly, it’s important to note that Coumadin (generic name: warfarin) is an anticoagulant, which means it stops the formation of blood clots and makes blood thinner (less viscous). As for Vitamin K, it helps the process of blood clotting. In other words, warfarin has the opposite effect to Vitamin K.

What is INR (International Normalized Ratio)? And how does it vary?

The INR is a test used by doctors and pharmacists to check the effectiveness of blood thinning medication (Coumadin/warfarin) and to adapt the dosage. Ideally, you should maintain as stable an INR as possible, meaning you should maintain an optimal blood coagulation rate.

Several factors can influence and unbalance this rate, the seven main ones are:

  • Travelling
  • Moving home
  • Depression
  • Divorce
  • Bereavement
  • Malnutrition
  • Dementia

Other factors include genetics, diet, adherence to treatment and other medications you may be taking. Natural supplements are included in the list of medicines that can affect INR.

Natural Supplements and Anticoagulation Therapy

vitamines-supplements

For your information, here are a few examples of natural products that could influence your INR more than eating green vegetables:

  • Those which increase INR values:
    • Boldo and fenugreek
    • Cranberry juice (in large quantities)
    • Danshen
    • Devil’s Claw
    • Dong Quai
    • Garlic capsules
    • Ginger
    • Ginko biloba
    • Mayweed
    • Papain
    • Vitamin E (in doses larger than 400 units/day)
  • Those which reduce INR values:
    • Coenzyme Q10
    • Ginseng
    • Green tea (in large quantities)
    • St. John’s Wort

Always speak to your pharmacist before you start or stop taking a supplement. If you take supplements, make sure you tell your doctor and your pharmacist.

Now that we’re reviewed some basic facts, let’s get to the nitty gritty: diet and its effect on medication! Several vegetables, particularly green ones, contain Vitamin K, in varying quantities. As mentioned earlier, warfarin (Coumadin) is a Vitamin K antagonist. Its presence or absence from the diet can play a role in the medication’s effectiveness.

Why You Shouldn’t Avoid Green Vegetables

food basket, paniel d'aliments

Two main reasons can explain why reducing your intake of green vegetables is not necessary, even if you’re going through anticoagulation therapy.

Firstly, despite what you might have heard, the presence of Vitamin K in the diet helps better balance your INR. Indeed, regularly eating vegetables, particularly green ones, helps you to be less sensitive to daily variations in Vitamin K. This is explained by the fact the liver stocks some Vitamin K, because it is a fat soluble vitamin.

For example, if you eat green vegetables every day, your liver stores Vitamin K. If, one day, you have a lower intake of Vitamin K, this will have practically no repercussions. Vitamin K stored in the liver will be used. This way, you can maintain you INR as stable as possible. However, if you never eat green vegetables, you don’t have Vitamin K stores, so if you eat a good amount of green vegetables one day, you’ll experience a “peak” of Vitamin K, which will then destabilize your INR.

Secondly, Vitamin K’s bioavailability depends on several factors like cultivation, storage and cooking of foods. What’s more, we only know the Vitamin K content of around half the food in the North American diet. It’s therefore practically impossible to establish and respect a recommended daily intake of Vitamin K.

For these reasons, we recommend an intake of 1 to 2 portions of green vegetables each day, even for those taking Coumadin. This quantity enables you to have a better control of your medication and to meet the nutritional needs established by Health Canada. What’s more, green vegetables are great for health!

Note: if you are a fan of Asian cuisine and regularly eat natto (a traditional Japanese food made from fermented soya beans), it would be a good idea to avoid it, because it contains a large quantity of Vitamin K (much higher than what is commonly found in vegetables), which can influence your INR.

Main food sources of Vitamin K

cabbage-chou

High Content Cabbage, Brussels sprouts, spinach, kale, turnips
Average Content Asparagus, avocado, broccoli, carrots, celery, cauliflower, red cabbage, cucumber, watercress, green beans, oils (canola, olive, soya), lettuce (Boston, Iceberg, romaine), fresh parsley, leek, green peas, tomato

So, in answer to the original question, no, it isn’t necessary to avoid green vegetables because the Vitamin K they contain enables a better control of both coagulation and medication. Good to know, those who have the most difficulty managing their INR are often those who do not eat (or do not eat enough) Vitamin K and green vegetables.

Our heart-healthy menus are approved by the nutritionists at EPIC, Montreal Heart Institute’s Center for Preventative Medicine, even for their anticoagulation therapy patients. Why not give them a try to help plan your meals?

autopromo_demo_heart_healthy_en


References

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Author

Jef L'Ecuyer

Jef L’Ecuyer

Registered Dietitian, RD at SOScuisine.com

Member of the Quebec College of Dietitians (OPDQ) and Dietitians of Canada,Jef graduated from McGill University in December 2014. Recently graduated and passionate about culinary arts, Jef poses a simple, effective and practical look at daily meal planning. With this in mind, she works in conjunction with the mission of SOSCuisine…

Jef L'Ecuyer

Latest posts by Jef L’Ecuyer (see all)

21 Responses to “Blood Thinners and Greens: A Mix to Avoid?”

February 11, 2019 at 4:25 pm, Virginia Davis said:

Hi,
Your article did not mention collard greens. Are they high in vitamin K as well? My mother loves collard greens and taking Warfarin at the moment. Her doctor has said no to green veggies. I hope that this article can apply to her.
Thanks.
Virginia

Cinzia Cuneo

February 11, 2019 at 4:33 pm, Cinzia Cuneo said:

Hi Virginia,
Yes, the same applies to collard greens. Your mother needs to keep her consumption always at about the same level.

February 19, 2019 at 12:52 pm, marlin said:

ALWAYS first check with your healthcare pro before starting supplements OR changing your dietary preferences. You can shock your metabolism and totally mess it up. What works for some don’t work for all. Many supplement also interact with med’s or other supplements. Don’t take chances, as first.

February 20, 2019 at 6:21 am, Spencer Ryce said:

Blood thinners are medicines that prevent blood clots from forming. They also keep existing blood clots from getting larger. Clots in your arteries, veins, and heart can cause heart attacks, strokes, and blockages.

There are two main types of blood thinners. Anticoagulants such as heparin or warfarin (also called Coumadin) slow down your body’s process of making clots. Antiplatelet drugs, such as aspirin, prevent blood cells called platelets from clumping together to form a clot.

March 15, 2019 at 1:16 pm, Luciano Tortorici said:

Very clarifying and helpful article. Thank you.

April 12, 2019 at 12:05 pm, Daniel said:

Hello, I have been taking warfarin and clopidogrel for several years now, 10mg warfarin daily and 75mg of clopidogrel. I also take nicorandil,bisiprolol,atorvastatin,ramipril and bumetanide. My INR has dropped to 1.2 and I’m not able to travel to the hospital for two or three days due to mobility issues, I have no money to pay for public transport either. My diet has changed for the better recently and I’m consuming many more potions of green leafy vegetables. Could this have had such a drastic impact on my INR? should I be worried?

Jef L'Ecuyer

April 12, 2019 at 12:14 pm, Jef L'Ecuyer said:

> Hello Daniel!

Improving your diet and consuming more leafy greens can definitely have an effect on your INR. You should check-in with your medical team to make sure your medication is adjusted accordingly.

April 25, 2019 at 7:27 am, Spencer Ryce said:

Anticoagulants such as heparin or warfarin (also called Coumadin) slow down your body’s process of making clots. Antiplatelet drugs, such as aspirin, prevent blood cells called platelets from clumping together to form a clot. When you take a blood thinner, follow directions carefully.

May 05, 2019 at 6:50 pm, Neal said:

I AM CURRENTLY TAKING BRILINTA..
WHAT VEGETABLES CAN I HAVE WHILE I MEDICINE?

Jef L'Ecuyer

May 06, 2019 at 1:04 pm, Jef L'Ecuyer said:

> Hi Neal!

Unless contraindicated by your medical team, you can eat a variety of veggies. There is no vegetable that should be left out, just make sure to have a serving of green veg everyday.

May 11, 2019 at 3:59 pm, Pam Busby said:

I love fresh turnip greens when in season. I’m taking Eliquois since I had a stroke last January. Should I stop eating turnip greens?

Cinzia Cuneo

May 21, 2019 at 8:32 am, Cinzia Cuneo said:

Hi Pam,
If you like them, you should eat them. In fact you should have a serving of green veg everyday.

May 23, 2019 at 5:32 pm, Steve said:

My mom had a stroke and is now on Plavix, low dose aspirin, and Lipitor daily. I’m doing the cooking and regularly use fresh garlic, lime, lemon, parsley, ginger, cabbage, kale, basil, and rosemary and dried spices like oregano, black pepper, red pepper, lemon grass, Herbs du Provence, and Korean spices like gochujang. Should I cut any of these out of her diet to avoid harmful interactions with her medications?

Cinzia Cuneo

May 24, 2019 at 2:08 pm, Cinzia Cuneo said:

Hi Steve,
As mentioned in the article, it is important that your mom keeps her leafy greens consumption constant, for example always one serving per day.

May 28, 2019 at 6:51 pm, kim glover said:

I am on warafin for prone to bloodclots in my leg. I have my own blood testing machine and todays results were 3.6,,so, if I eat more salad with spinach in it, will that help bring my level down where it should be?

July 05, 2019 at 6:56 pm, Ana said:

Hi! I have just started taking Xarelto. Should I avoid greens?

Cinzia Cuneo

July 10, 2019 at 11:04 am, Cinzia Cuneo said:

Hi Ana,
As explained in the article, you should not avoid eating greens. You should only pay attention to keep the consumption always at about the same level.

July 22, 2019 at 11:57 am, Linda Brown said:

hello I am taking medications like Lisinopril, amlopodine, atorvastatin clopidogrel, plavix aspirin. I eat broccoli three days a week is this a bad idea

August 21, 2019 at 10:13 pm, Marcia Green said:

Hi, I am confused, if your INR is at 3 does that mean your blood is thick and say 1 means it is thin? Lower number means thin??

December 04, 2019 at 5:56 pm, Sue Thornley said:

I am taking Apixaban
tablets after a blood clot last Christmas in my lungs. Is it ok for me to eat green veg despite the clot? I would be grateful to receive your views. I do miss eating them. Also, should I be avoiding any type of food? Thank you.

Cinzia Cuneo

December 11, 2019 at 10:27 am, Cinzia Cuneo said:

Hi Sue,
As explained in the article it is important to keep a regular pattern of eating greens.

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