Warfarin and Supplement Interactions – and What About Food?

Way back in 1988 I was Editor of a book called The Medicine Chest which was a straightforward examination of the interactions between drugs, supplements and foods. It had a lot of good advice that hasn’t changed much over the years so I was surprised to receive a ‘news’ item that warned that Warfarin when taken with vitamin E and large doses of vitamin C can decrease effect of the drug.

I was not surprised at the effect because I was writing about it over 20 years ago, but that it was news came as a surprise. However, it never hurts to repeat a good piece of information and scientists never turn up a chance for a grant to research something we already know.

This time it is researchers at the Intermountain Medical Center Heart Institute in Salt Lake City, Utah who want to point out the dangers. Warfarin is a commonly prescribed drug used to prevent blood clots from forming and given to people with certain types of irregular heartbeat, those with prosthetic heart valves, and those who have suffered a heart attack.

The study consisted of interviews with 100 atrial fibrillation patients to determine their understanding of potential interactions between supplements and medications such as Warfarin. This is not really a study about interactions but of people’s understanding of them and generally people do not know enough about how supplements, and everyday foodstuffs react with their medication.

In this study more than half were unaware of potential interactions and they also found that of the 100 most-used supplements (vitamins, glucosamine/chondroitin, fish oil and coenzyme Q10) 69 percent interfere with the Warfarin’s effectiveness.

Warfarin and herbal and dietary supplements “compete” in the liver and this competition changes the way the blood thinner works — either intensifying its active ingredients, thereby increasing the risk of bleeding, or by reducing its effectiveness, increasing the risk of stroke.

All true, and the lead researcher is urging that doctors do a better job of teaching patients about the dangers of mixing Warfarin with these products. Now I entirely agree with him, but what he doesn’t mention is that this particular drug is also seriously affected by certain foodstuffs and other drugs.

Given what the average doctor knows about nutrition I hold out little hope they will also pass on this advice so that instead of increasing or decreasing their drug prescription they could suggest changes to their patients diet. In addition, the effectiveness of Warfarin is impacted by other drugs – particularly antifungals, barbiturates and beta blockers which all decrease the drugs effectiveness.
Conversely, antibiotics, some diabetes drugs, gout medicines, tricyclic antidepressants and asprin and paracetamol – among others – all can increase the drug’s effectiveness, making it more potent.

On Warfarin? Avoid These:
Warfarin is affected by large doses of vitamin E, vitamin C, bioflavanoids and calcium and a large intake of fats or oils. If the diet is also high in vitamin K rich foods this can cause an imbalance in the body which could decrease the anticoagulant effect.

Vitamin K is needed to allow your blood to clot normally, to protect your bones from fracture and postmenopausal bone loss, to prevent calcification of the arteries and provide possible protection against liver and prostate cancer.

Vitamin K is a fat soluble vitamin and only a small amount is able to be stored in the body. It is destroyed by light and acids and alkalis such as vinegar or baking soda. A deficiency of it can lead to increased blood clotting time, easy bruising and excessive bleeding.

Significant food sources include: green leafy vegetables including spinach, Brussels sprouts, Swiss chard, green beans, asparagus, broccoli, kale and also cauliflower, cow’s milk, eggs, fish liver oils, green vegetables, kelp, liver, molasses, polyunsaturated oils, tomatoes

Everyone responds differently to drugs, foods and supplements so if you have any concerns, or if your diet is high in vitamin K rich foods, then you should discuss with your doctor how this is affecting your medication.

Low Vegetable Intake During Pregnancy Can Increase Baby’s Diabetes Risk by 70%

April 14, 2010 by  
Filed under Health


Diabetes UK estimate that seven million people in the UK are at risk of developing diabetes, which can lead to other significant health problems by affecting the nerves, kidneys, eyes, and heart. It can lead to greater susceptibility to strokes and cause blood clots in the vessels in the legs which may result in amputation. Diabetes is the leading cause of blindness in the working population as it can affect the blood vessels at the back of the eye [retinopathy] and this can lead to visual impairment or blindness.

With this in mind, it makes sense to start early prevention and new research published in the journal Pediatric Diabetes undertaken by the University of Gothenburg and Linkoping University in Sweden offers some hope for that. It seems that women who eat more vegetables while pregnant significantly reduce their children’s risk of developing Type 1 diabetes, an autoimmune disease that develops when the immune system produces antibodies that attack the insulin-producing cells in the pancreas.

Researchers tested the blood of 6,000 five-year-old children for these antibodies, and compared the results to their mothers’ self-reported vegetable intakes (excluding root vegetables such as potatoes, beets and carrots) during their pregnancy. They found children whose mothers had eaten vegetables only three to five times a week while pregnant were 70 percent more likely to have elevated antibody levels than children whose mothers ate vegetables every day. In this study the most frequently consumed vegetables were tomatoes, cabbage, onions, lettuce and cucumbers.

The researchers found that this positive effect remained after researchers adjusted for other Type 1 diabetes risk factors, such as mother’s education level. The reason lies yet again with those vital flavonoids in fruit and vegetables as these powerful antioxidants have previously been suggested to be potentially therapeutic agents for Type 1 diabetes. Vegetables also containing vitamin C and vitamin E have also been shown to reduce the risk of Type 1 diabetes.

If you are pregnant, or planning to start a family, or know someone who is then it would be a good deed to encourage them to up their fruit and vegetable intake not only for their own wellbeing but for the long term health of their baby.

For more information on diabetes, please visit www.diabetes.org.uk

Vitamin E in Contact Lenses Could Treat Glaucoma

April 12, 2010 by  
Filed under Health


Glaucoma is second only to cataracts as the leading cause of vision loss and blindness in the world as it affects almost 67 million people. Eye drops that relieve the abnormal build-up of pressure inside the eye that occurs in glaucoma, are a mainstay treatment but now there may be an alternative.

Research carried out at the University of Florida reports that if vitamin E is added into special medicated contact lenses it can keep the glaucoma medicine near the eye. This means it can more effectively treat the condition, up to nearly 100 times longer than possible with current commercial lenses.

Anuj Chauhan, Ph.D., who headed the research team, explained: “The problem is within about two to five minutes of putting drops in the eye, tears carry the drug away and it doesn’t reach the targeted tissue. Much of the medicine gets absorbed into the bloodstream, which carries it throughout the body where it could cause side effects. Only about one to five percent of drugs in eye drops actually reach the cornea of the eye.”

Chauhan and his colleagues have developed a new extended-release delivery approach by incorporating vitamin E into contact lenses. The vitamin E molecules form a kind of transport barrier that slows down the release of the glaucoma medication from the lens into the eye. The drug molecules can’t go through the vitamin E but must go around it and so get diverted and must find a longer path into the bloodstream. This increases the duration of the drug release from the lenses and so stays in the tears far longer than the 2-5 minutes with eye drops, leading to more effective therapy.

Don’t – please don’t – try adding vitamin E to your own contact lenses as this is very much in the development stage, but it is hoped clinical trials of the new lenses could begin within a year to 2 years.

Vitamin E Can Prevent Nerve Cell Death After A Stroke

January 20, 2010 by  
Filed under Health


A study at Ohio State University has shown that blocking the function of an enzyme in the brain with a specific kind of vitamin E can prevent nerve cells from dying after a stroke. Following the trauma of blocked blood flow associated with a stroke, an excessive amount of glutamate is released in the brain. Glutamate is a neurotransmitter that, in tiny amounts, has important roles in learning and memory. Too much of it triggers a sequence of reactions that lead to the death of brain cells, or neurons — the most damaging effects of a stroke.

Tocotrienol, a form of vitamin E, works by stopping the enzyme from releasing fatty acids that eventually kill nerve cells. It has already been studied over the last ten years and has been established that this form of vitamin E protects the brain in animals though not conclusively proved yet in humans.

Vitamin E occurs naturally in eight different forms; 4 forms of tocopherol and 4 forms of tocotrienol. While tocopherols are generally present in common vegetable oils like soy, wheat germ and sunflower, tocotrienols are concentrated in cereal grains such as oat, barley, rye, and rice bran. The various different forms of natural vitamin E have distinct functions and tocotrienol targets specific pathways to protect against neural cell death and rescues the brain after stroke injury

Tocotrienols and tocopherols are potent antioxidants that are 100% natural and can be derived from rice bran oil and palm oil distillates and are available in supplement form. Tocotrienol or TCT, is not abundant in the western diet but is a common component of a typical Southeast Asian diet.

What is interesting is that the amount of tocotrienol needed to achieve these effects is quite small — just 250 nanomolar, a concentration about 10 times lower than the average amount of tocotrienol circulating in anyone who regularly takes vitamin E. The benefits of vitamin E are well known for health, it a acts as a powerful antioxidant by neutralizing free radicals in the body that cause tissue and cellular damage and contributes to a healthy circulatory system.

Natural help for eyes

As we get older our eyes become vulnerable, and around 1 in 7 over 55 year olds will suffer from macular degeneration. This is the leading cause of blindness and severe vision impairment worldwide, and a study in the Archives of Ophthalmology reports on the benefits of Omega-3 for reducing the risk.

Macular degeneration (MD) affects central vision and this gradually deteriorates causing functional blindness. Peripheral vision is not at first greatly affected; but over time peripheral vision is also reduced. A study of 8,000 people in the Netherlands found that those who developed the disease were more likely to be smokers and have high cholesterol and that because free radical damage has been linked to MD that antioxidants can reduce the disease’s progress.

However, a more recent study has shown a clear link between consumption of Omega-3 and reduction in age-related MD. Dr Chong of the University of Melbourne did a meta-analysis of nine studies which covered 90,000 people, and 3000 of those had age-related MD.

Back to the benefits of fish again, because her study found that eating just one portion of Omega-3 rich fish may reduce the risk of contracting MD by over 50%. In fact increasing your daily intake by 300 mg per day of the Omega-3 fatty acids DHA and EPA, reduces the risk of MD by about 70%.

If fish really isn’t your favourite then you can get Omega-3 from flaxseed oil which is also rich in lutein and that’s one of the antioxidants that boosts eye health and prevents cataracts and macular degeneration. These are the essential elements for good eye health:

BETA-CAROTENE which destroys free radicals and helps keep eye tissue healthy.

VITAMIN C and VITAMIN E are antioxidant and protect the eye from sun damage

ZINC and COPPER are antioxidant and protect our eyes

B VITAMIN complex to fight free radicals in your eyes, particularly the cornea and the myelin sheath around the optic nerve

TAURINE is an essential amino acid for retina health and blocks out UV rays and environmental toxins.

EYEBRIGHT is a herb that been traditionally used to relieve irritated eyes and strengthen blood vessels in the eyes.

Otherwise it’s the usual mix of dark green leafy vegetables, particularly spinach, and a varied daily diet to keep your eyes sparkling.

Vital Veg – The dynamic duo

August 2, 2008 by  
Filed under Food & Nutrition, Natural Medicine, Wellness

Cabbage is not everyone’s favourite food – shades of school dinners and that terrible lingering smell as it boiled away all morning – and celery, too, can be an acquired taste you either love or loathe, but these two vegetables can immeasurably improve your health. Here are some of the really good reasons to include cabbage in your diet on a regular basis:

On a diet? An average portion is around 15 calories, so it can help you lose weight, while feeling full. It is also full of vitamin C which many believe helps your cells to burn fat.

It contains phytonutrients that help protect you from the free radicals (cancer causing agents) that can damage your cell walls.

Helps to clean and detox your liver of impurities by stimulating the production of the antioxidant glutathione.

The lactic acid in it can help disinfect your colon to inhibit growth of bacteria.

Promotes healthy, glowing skin because of the amounts of vitamin E it contains.

Keeps your eyes healthy with a good dose of vitamin A. All that applies to the white and green cabbage varieties, however if you add in some red cabbage you will be getting a bonus in the form of anthocyanin, an antioxidant which is responsible for its red colour. However it’s not there just to make it look good alongside your Lancashire hotpot, the traditional accompaniment to this winter dish. It has several vital roles to play in supporting your mental health as it helps protect your brain cells, and this is the reason many scientists now believe it could have a role in the fight against Alzheimer’s. Again, like it’s green cousins, it can also help if you are dieting as anthocyanins also have potential as ‘fat-fighters’, according to a Japanese study carried out in February 2008. They reported that the antioxidants in red cabbage could help tackle metabolic syndrome (MetS), which can cause obesity, hypertension, and insulin problems.

Enough about cabbage – what about celery? In my childhood it appeared in water in a cut glass jug to accompany Sunday tea and I avoided it like the plague. Now, I enjoy it on a daily basis – more later. So what is celery good for? Well more good news for dieters, as it can help suppress your appetite and that can help you slim. If you are an anxious type then celery can be useful as it has a calming effect on the central nervous system. Celery contains ‘pthalides’, compounds which can help relax your artery muscles, and have an effect on lowering your blood pressure – always a good idea if you are anxious, and those same compounds also reduce your levels of stress hormone, which help keep your blood vessels relaxed and open. It’s the leaves, rather than the stalks that contain the biggest concentration of the pthalides, so chop finely and add to salads, don’t just eat the crisp stem.


I promised an easy way to eat these two vital veg, and I will let you into a secret. I really don’t like eating vegetables at all. There are a favoured few, but mainly I count potatoes as my only ‘much-loved’ vegetable. But, I know how important it is to get those nutrients, so I juice my vegetables instead. The quickest way to get the benefits of cabbage is to drink 25-50 ml of fresh, raw cabbage juice each day. This is based on research done in the early 1950s by Dr Garnett Cheney who found that peptic ulcer patients who drank 4 glasses of raw cabbage juice daily quickened the healing process and relieved the pain. A quarter of an average cabbage will give you that amount, throw in some celery with the leaves and you have an amazing cocktail. If you want it a little sweeter pop in a carrot. You can juice pretty much anything and everything, and there are some great juice recipe books on the market – please try to use organic veg where possible and drink the juice the second you have made it – don’t let it stand or it will start to oxidise on contact with the air and it doesn’t look very pretty either. I start the day usually by juicing an apple, a carrot, couple sticks of celery, half a grapefruit and a piece of ginger. If you haven’t time for breakfast, then that will really set you up.

Antioxidants for ‘airport ears’

Do you live near to an airport or are you often exposed to loud noise on a regular basis? Are you suffering from hearing loss because of it? If so, you may be interested to hear of some new research, at present only being carried out on guinea pigs, that seems to show that having a good level of antioxidants might just make all the difference. The University of Michigan Hearing Research Institute carried out the study and they gave the guinea pigs a mix of antioxidants: vitamins A, C, and E, and magnesium one hour before they were exposed to the equivalent decibel level comparable to a jet engine taking off. The guinea pigs continued to be given the same amount of the antioxidant mix for a further five days after that single event. A test group were also exposed to the same decibel level, but with no antioxidants given.

When they compared the hearing levels of the two groups at the end of the five-day period, the group that had taken antioxidants experienced a significantly lower loss of hearing. So could it help us too? I will pass on information on phase two of the research, where the Michigan researchers are testing the same antioxidants on soldiers who are exposed to high decibel levels during training, and indeed often very frequently afterwards.