Tag: warfarin

Broccoli and Spinach are Not Likely to Affect INR Blood Test

Claus Hancke

December 10, 2004

Promising Dutch study of Vitamin K. The somewhat cryptic headline is probably nonsense to most people, but nevertheless has great importance to all those taking blood-thinning (anticoagulating) medicines such as Marevan (Warfarin) and who are doing the regular blood test control, called INR.

If you are undergoing treatment with anticoagulant drugs such as Marevan, you should regularly be tested with a blood test called INR.

This blood test is designed to estimate if the dose you receive is correct, but it should also prevent overdosing in which the blood would get “too thin”. This condition is dangerous and can result in internal bleeding.

12 healthy volunteers were included in a study in which they were given a correct dosage of anticoagulants for 13 weeks and adjusted to a maintenance dose with a constant and stable INR value that would prevent them from forming blood clots.

Then, they were given increasingly large daily doses of vitamin K from 50 mcg. to 500 mcg. during the course of one week. Not until the dose reached 150 mcg. of vitamin K a day taken as a dietary supplement, was any effect on INR observed. Even at this dose, INR was only affected in 3 out of the 12 trial subjects.

When the trial subjects were given food that is particularly rich in vitamin K, i.e. broccoli and spinach, there was no clinically relevant effect on INR because the effect was so transient, and the authors suggest that the reason might be a poor bioavailability of the vegetables. This may be surprising, as kale, spinach, and broccoli can contain up to 400 mcg. of vitamin K per 100 g.

Doses of 100 mcg. vitamin K as an easily absorbable dietary supplement had no effect on INR.

If this study on healthy, young trial subjects can be repeated with the same result on patients with a predisposition to forming blood clots, it would make life significantly easier on a great number of people who every day stare in despair at the long list of foods containing vitamin K that they are not allowed to eat while taking Marevan.

By: Vitality Council

Reference:
Schurgers LJ, Shearer MJ, et al: Effect of Vitamin K Intake on the Stability of Oral Anticoagulant Treatment. Dose-Response Relationships in Healthy Subjects. Blood 2004;104(9):2682-2689.

www.bloodjournal.org
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Q10 and Ginkgo biloba may be taken together with blood thinners

Claus Hancke

May 5, 2003

Q10 and Ginkgo biloba may be taken together with blood thinning medication. A Danish study shows that it is non-dangerous to take the two supplements together with the blood diluting substance Warfarin.

An article in the danish medical journal, Ugeskrift for læger, rejects the suspicion that the two supplements may either weaken or enhance the effect of Warfarin (Marevan), which is typically used in the prevention and treatment of blood clots, eg in the heart or brain.

The study included 24 patients who were on long-term treatment with Warfarin, and no clinically significant difference was found between those who received placebo and those who received Warfarin.

General practitioner Claus Hancke from Lyngby is pleased that the misconception that there were problems with mixing these drugs has now been dispelled. “It is of great importance that patients with heart failure, who often receive Marevan as a blood thinner, can now once again improve the heart’s pumping ability with Q10,” says Claus Hancke, chairman of the Vitality Council.

He also emphasizes the importance of all patients taking cholesterol-lowering medication, the so-called statins, that they also take Q10 to prevent serious long-term side effects of the cholesterol-lowering medication.

There is a great need for research into the combination of prescription medications and dietary supplements, which is why the new study has great value for both doctors and patients.

A good five percent of the Danish population regularly takes Q10, which is a vitamin-like preparation containing coenzyme Q10, creating energy in the cells. Many do so because they have heart problems, and therefore some of the patients will also be taking Warfarin.

Ginkgo biloba is also used by a large part of the population. It is especially used to improve blood flow if you have problems with cold hands or impaired memory.

By: Vitality Council

Reference:
Ugeskrift for Laeger, 28. April 2003, no. 18.

www.dadlnet.dk
www.iom.dk