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Vitamin E and Anticoagulant Therapy


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Vitamin E and Coumadin

Q:??In an article dated May 24, 1999, you indicated that taking Vitamin E was not a problem if you are on Coumadin. However, I enclose the printout I received from my pharmacy when I first began to take Coumadin, which indicates that Vitamin E may interact with Coumadin. Additionally, I enclose a copy of my Johns Hopkins Medical Newsletter of May 19, 1999, which indicates that if you are taking Coumadin, you should avoid megadoses of Vitamin E because it is a nutrient that affects circulation. I think you may want to reconsider your suggestion in your May 24th article and perhaps suggest that a reasonable amount of Vitamin E might be 200 international units, at the most. What do you think?

Q: In your column in the Health and Science Section of the Milwaukee Journal Sentinel, you answered a question regarding taking Coumadin and Vitamin E. Your response was that Vitamin E should not affect the Protime level. I am 72 years old and am taking Coumadin because of a blood clot condition in my leg. I was very disappointed when my doctor advised me that I definitely could not continue taking Vitamin E because it would affect my Protime level. Therefore, I am confused after reading your May 24th column.

A:??Vitamin E at doses of 100 or 400 units a day, when given to people on Coumadin (warfarin), did not affect their protime level (measure of the their blood clotting) in at least two studies. The most recent of the studies, done at the University of California at Davis and published in 1996 in the American Journal of Cardiology, concluded that "vitamin E can safely be given to patients who require chronic warfarin therapy." The Johns Hopkins article cautions against megadoses of vitamin E, which would be in the range of 1000 units or more, but according to research on people and animals, 400 units a day should be fine.

Article Created: 1999-09-07

Article Updated: 2003-01-13

Dr. Rebekah Wang-Cheng is a former Professor of Medicine at the Medical College of Wisconsin. Her medical advice column, which answers health-related questions from readers, also appeared in the Milwaukee Journal-Sentinel.

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Warfarin (Coumadin) is an anticoagulant drug used to treat thromboembolitic disorders and is given to some patients with a history of heart attacks, transient ischemic attacks (mini strokes), and strokes. It is commonly used to prevent strokes in those with enlarged hearts and various arrhythmias such as atrial fibrillation.

Vitamin K

Warfarin reduces coagulation of blood by interfering with the actions of vitamin K. Therefore, under most circumstances (see the next paragraph for exceptions), it is important for people taking this drug to avoid vitamin K supplementation, including multivitamins containing vitamin K. It has also been recommended that people taking anticoagulants avoid foods high in vitamin K, such as kale and parsley, and to limit intake of spinach, other greens, broccoli, and Brussels sprouts, which also contain significant amounts of vitamin K.1 Such dietary restrictions should be discussed with the prescribing physician.

Vitamin K supplementation can be used, however, to counteract the effects of excessive doses of anticoagulants such as warfarin.2 Such administration requires the supervision of a doctor.

Coenzyme Q10

Coenzyme Q10 is structurally similar to vitamin K and has been reported to interfere with warfarin activity in three people.3 It remains unknown how common or rare this interaction is. Those taking warfarin should only take coenzyme Q10 with the guidance of their doctor.

Vitamin D

Years ago, an isolated letter to the Journal of the American Medical Association suggested that vitamin D increases the activity of anticoagulants and that this interaction could prove dangerous.4 Perhaps because vitamin D is in multivitamins taken by tens of millions of people and other reports of problems have not surfaced, most doctors typically do not tell patients taking anticoagulant medications to avoid vitamin D.

Vitamin E

Similarly, an isolated case of vitamin E increasing the activity of anticoagulants was reported years ago.5 This isolated case received much attention and has concerned some conventional medical doctors.6 However, using more stringent methodology, researchers have recently found that vitamin E (up to 1,200 IU per day) does not alter the effects of warfarin and appears completely safe for people taking this drug.7 Therefore, it does not appear that people taking anticoagulants need to avoid vitamin E.

Vitamin C

Although case reports have suggested that vitamin C might increase the activity of anticoagulants in a potentially dangerous way, this interaction has not been confirmed in research studies.8


In theory, bromelain might potentate the action of anticoagulants. This theoretical concern has not yet been substantiated by human research, however.9

Dan Shen (Salvia miltiorrhiza)

Dan shen, a Chinese herb, may cause bleeding in people taking Coumadin.10 11 Dan shen should only be used by people taking Coumadin under close medical supervision. A related plant found in the west, Salvia (sage), is safe for use with Coumadin, however.

Garlic (Allium sativum)

Garlic helps prevent atherosclerosis but may promote bleeding, as it stops platelets from sticking together.12 This makes it hypothetically problematic to combine with Coumadin. Potent standardized extracts might be more likely to cause a problem. Anyone with a history of bleeding problems who is taking Coumadin should only take such extracts on the advice of a knowledgeable health care practitioner.

Ginkgo (Ginkgo biloba)

Ginkgo inhibits platelet adhesion, thereby increasing the tendency toward bleeding.13 Reports of problems of combination with ginkgo and Coumadin are rare but remain a theoretical concern.


1. Harris JE. Interaction of dietary factors with oral anticoagulants: Review and applications. J Am Dietet Assoc 1995;95:580?84 (review).

2. Weibert RT, Le DT, Kayser SR, et al. Correction of excessive anticoagulation with low-dose oral vitamin K1. Ann Intern Med 1997;125:959?62.

3. Spigset O. Reduced effect of warfarin caused by ubidecarenone. Lancet 1994;344:1372?73 (letter).

4. Schrogie JJ. Coagulopathy and fat soluble drugs. JAMA 1975;232:19 (letter).

5. Corrigan J, Marcus FI. Coagulopathy associated with vitamin E ingestion. JAMA 1974;230:1300?1301.

6. Anonymous. Vitamin K, vitamin E and the coumarin drugs. Nutr Rev 1982;40:180?82 (review).

7. Kim JM, White RH. Effect of vitamin E on the anticoagulant response to warfarin. Am J Cardiol 1996;77:545-6.

8. Harris JE. Interaction of dietary factors with oral anticoagulants: Review and applications. J Am Dietet Assoc 1995;95:580?84 (review).

9. Harris JE. Interaction of dietary factors with oral anticoagulants: Review and applications. J Am Dietet Assoc 1995;95:580?4 (review).

10. Yu CM, Chan JCN, Sanderson JE. Chinese herbs and warfarin potentiation by ?danshen.? J Intern Med 1997;241:337?39.

11. Tam LS, Chan TYK, Leung WK, Critchley JAJH. Warfarin interactions with Chinese traditional medicines: Danshen and methyl salicylate medicated oil. Aust NZ J Med 1995;25:258.

12. Rose KD, Croissant PD, Parliment CF, Levin MB. Spontaneous spinal epidural hematoma with associated platelet dysfunction from excessive garlic ingestion: A case report. Neurosurg 1990;26:880?82.

13. Rosenblatt M, Mindel J. Spontaneous hyphema associated with ingestion of Ginkgo biloba extract. New Engl J Med 1997;336:1108.

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Vitamin E

An isolated case was reported in 1974 of vitamin E (up to 1,200 IU per day) being associated with increased anticoagulation (blood thinning) in a patient treated with warfarin.11 A study of 12 people undergoing warfarin therapy found that additional vitamin E (100 IU or 400 IU per day) did not induce a clinical bleeding state.12 Moreover, a double-blind trial found that supplementation with vitamin E in amounts up to 1,200 IU per day had no effect on warfarin activity.13 It now appears safe for people taking warfarin to supplement vitamin E despite information to the contrary often provided by doctors about this purported interaction. These warnings are based on the isolated case report from 1974.

11. Corrigan J, Marcus FI. Coagulopathy associated with vitamin E ingestion. JAMA 1974;230:1300?1.

12. Corrigan JJ Jr, Ulfers LL. Effect of vitamin E on prothrombin levels in warfarin-induced vitamin K deficiency. Am J Clin Nutr 1981;34:1701?5.

13. Kim JM, White RH. Effect of vitamin E on the anticoagulant response to warfarin. Am J Cardiol 1996;77:545?6.

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Natural VITAMIN E 500iu

Provides superior absorption and effectiveness over synthetic forms.


Vitamin E is a fat-soluble vitamin first identified in the 1920's. Its chemical name, dl-alpha tocopherol was derived from one of the Greek words for birth. Early studies with vitamin E show it is required for fertility and maintaining pregnancy in certain animals. Although there is no support for a role in human fertility, the name tocopherol remains.

Herron Vitamin E is derived from Soybean oil.

Therapeutic effects

1. Antioxidant activity

2. Assisting in the maintenance of peripheral circulation

3. Relief of pre-menstrual syndrome

Free radicals are chemically unstable atoms or molecules, which can be generated by normal metabolism or by lifestyle factors such as excess dietary fats, cigarette smoke, alcohol consumption, pollutants and stress. Antioxidants help to counteract the effects of free radicals and oxidation in the body. Vitamin E is considered to be one of the major antioxidants.

Vitamin E supplementation helps to maintain the health of the capillaries and assist in the improvement of general well being. Vitamin E assists maintenance of cell membranes. It may also assist in the wound healing process and in preventing scar tissue formation in burns and sores.

Pre-menstrual syndrome (PMS) is characterised by physical symptoms such as breast tenderness, abdominal bloating, swelling of fingers or ankles, mild anxiety and mild irritability. Vitamin E may assist in the relief of symptoms of PMS, menstrual cramps and pre-menstrual breast pain, at doses of 400IU daily. Use only as directed and consult your health care professional if pain or discomfort persist.


Take 1 capsule per day, or as prescribed by your practitioner.

Vitamin supplements should not replace a balanced diet.

Side Effects

Vitamin E in daily doses up to 1200IU has recently been shown to be safe in a small study (13 patients) for patients taking the blood-thinning drug, Warfarin. For those on blood thinning medication, medical supervision is recommended so that clotting time may be monitored before starting vitamin E therapy.

Vitamin E therapy has been known to increase blood pressure in the short term if starting on a high dose. If high blood pressure is a problem, medical supervision is advised.

Further Reading

Butler EB, McKnight E. Vitamin E in the treatment of primary dysmenorrhoea. Lancet1, 1955.

Jain SK et al. The effect of modest vitamin E supplementation on lipid peroxidation products and other cardiovascular risk factors in diabetic patients. Lipids, 1996.

Killon SL et al. Vitamin E levels in human atherosclerotic plaque: the influence of risk factors. Atherosclerosis, 1996.

Kim JM, White RH. Effect of vitamin E on the anticoagulant response to warfarin. Am J Cardiology, 1996.

For more information on natural healthcare, please contact:

Herron Pharmaceuticals.

17 Curzon St, Tennyson Qld 4105

Phone: 1300 659 646

Email: custservice@herron.com.au

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  • 2 years later...


Vitamin E 'not a heart protector'

Vitamin E provides little protection against heart attacks, strokes and cancer - despite millions of people believing it does, a major study shows. Some previous trials had suggested it might be beneficial, prompting one in 10 US women to take it as a supplement. But a Women's Health Study of 40,000 women aged over 45, in the Journal of the American Medical Association, should settle the debate, say experts. The women were followed from 1992 to 2004 to see what effect vitamin E had.

The authors of the study, published in the Journal of the American Medical Association, say there is enough evidence now to tell healthy women that taking vitamin E will not protect them against the two big killers - cardiovascular disease and cancer. The women in the study were followed for a decade to see what effect vitamin E or aspirin taken every other day had on their risk of strokes and heart attacks and cancer. Some of the women received real tablets, while others received dummy pills.

Vitamin E (600 IU) did nothing to reduce cardiovascular disease risk. There were 482 heart attacks or strokes, some fatal, in the group of women who received vitamin E compared to 517 in the placebo group. In comparison, aspirin (100mg) reduced the risk of stroke overall in the women studied and the risk of both stroke and heart attack in those aged 65 and older.

When it came to cancer prevention, neither vitamin E nor aspirin appeared to work. But there was some suggestion that aspirin might prevent lung cancer. The 10mg tablets appeared to reduce the risk of lung cancer by a fifth and death from lung cancer by nearly a third. The researchers said this might be worth investigating further, as well as the possibility that higher doses might prevent other cancers. The Harvard Medical School team said their trial was "the longest of any completed to date" to look at such trends and should, therefore, "be sufficient to detect long-term effects". Dr Elizabeth Nabel, director of the National, Heart, Lung and Blood Institute, which funded the study, said: "We can now say that despite their initial promise, vitamin E supplements do not prevent heart attack and stroke. "Instead, women should focus on well proven means of heart disease prevention, including leading a healthy lifestyle." The researchers suggested that the fact that people who take vitamin supplements and eat food rich in vitamins tend to be generally more healthy anyway might explain why past work found a benefit with vitamin E.

Current US and UK guidelines do not recommend vitamin E for cardiovascular disease or cancer prevention. High doses of vitamin E and aspirin can be harmful. The British Heart Foundation said its own research had shown taking vitamin E has no significant effect on cardiovascular health. A spokeswoman advised: "Stopping smoking, lowering blood pressure and cholesterol levels, are the best known ways to prevent coronary heart disease. "People can also reduce their risk by increasing the amount of physical activity they take, reducing the amount of saturated fat and salt in their diet and eating at least five portions of fruit and vegetables per day. "Taking vitamin supplements should not be seen as a replacement for taking these measures." Ed Yong of Cancer Research UK said: "Studies have shown that aspirin could protect against certain types of cancer.

"A key difference could be in the doses tested. Cancer Research UK is currently funding large studies to investigate the potential benefits of aspirin in cancer prevention."

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