Warfarin is the most commonly prescribed anti-coagulant. It is often given to people with irregular heart beat or people who have suffered a heart attack/stroke or pulmonary embolism. How it works is that it prevents clots from forming or existing clots from growing in you blood vessels. Needless to say, these clots obstruct your blood flow and put your life in peril. Warfarin powerfully decreases these clots, enhances the smooth flow of blood and keeps you healthy.

Vitamin K (phylloquinone) is a vitamin that affects the blood clotting process in our body. Foods rich in vitamin K can reduce the anti-blood clotting effects of Warfarin. Listed below are common food items that may assert a medium to strong influence on the effects of warfarin:

Questions are frequently asked about the interaction between warfarin and herbal medicines. Often, ‘natural’ is regarded as ‘safe’ to most people; unfortunately this is not the case with Warfarin and herbs. There are a host of herbal medicines that possess natural anti-coagulant properties. Taken with warfarin, herbs may have additive effects and increase the potential for bleeding. Others, however, may antogonise the effects of Warfarin.

Below are herbs that increase the anti-coagulant effects of warfarin and cause bleeding:

Listed below are herbs that antogonise the effects of Warfarin, making you more at risk of forming clots:

It is best to avoid ‘coumarin – derivatives’ containing herbal teas as they may also interfere with Warfarin. Examples of these teas include the tonka beans, melot (sweet clover) and sweet woodruff.

Grapefruit juice, a common breakfast beverage in Europe, can adversely affect a drug’s absorption. It can cause a drug to be absorbed from the intestine and reaching toxic levels. Sometimes, it can prevent a drug from working at all. Therefore it is best to avoid eating grapefruit or drinking grapefruit juice 2 hours before or after taking medication. Studies on the interaction between grapefruit juice and Warfarin are inconclusive, so consume this juice with caution when taking Warfarin.

In conclusion, if you are on Warfarin, before taking any herbal, mineral or vitamin supplements, consult a dietitian or pharmacist. Please be warned that some effects may take 2-4 weeks before becoming apparent. It is important to inform your doctor of any changes.

References
1. Booth SL, Sadowski JA, Weibrauch JL, Ferland G. Vitamin K (Phylloquinone) contents of food: A provisional table. J Food Comp Anal 1993; 6: 109-20.

2. Suvarna R, Pirmohamed M, Henderson L. Possible interaction between Warfarin and cranberry juice. BMJ 2003; 327: 1454.

3. Cambria-Kiely JA. Effect of soy milk on Warfarin efficacy. Ann Pharmacother 2002: 36; 1893-6.

4. Stockley IH. Drug Interactions, 5th Edn. London: Pharmaceutical Press, 1999.

5. Makjeha AB. Bailey JM. A platelet phospholipase inhibitor from the medicinal herb feverfew (Tanscetum parthenium) Prostaglandins Leukot Med 1983; 8: 653-660.

In 2007, Professor Jennie Brand-Miller et al demonstrated in a simple but elegantly designed experiment to demonstrate the effect of alcohol (from beer, wine and gin) on blood sugar levels after a meal and found some astounding results.

This study found that alcohol has the potent ability to reduce blood sugar response after a meal. Of the 3 alcoholic beverages tested, wine was found to have the greatest blood sugar lowering effect (lowering the glucose score by 37%).

How can we explain this amazing result? Well, it is possible that alcohol may inhibit the production of glucose from our liver. Also, alcohol seems to slightly increase insulin sensitivity resulting in less sugar circulating in the blood. This ability to create a flatter blood sugar response or curbing sugar ‘spikes’ is vital in the prevention of heart disease and the control of symptoms of metabolic syndrome.

Hence, moderate intakes of alcoholic beverages particularly – wine (100ml per day), could be an important part of a healthy diet! As Jean-Anthelme Brillat-Savarin said, “A meal without wine is like a day without sunshine.”

References

1. Brand-Miller J et al. Am J Clin Nutri 2007; 85:1545-51.
2. Brand-Miller j et al. Curr Atheroscler Rep 2007; 9:479-85.

Quite on the contrary, linoleic acid (omega-6 fatty acid) has been proven to be the most potent cholesterol-lowering nutrient in the diet with impressive cardiovascular benefits (20-35% reduction in clinical cardiovascular end-points) according to a study by Ascherio in 2002. Where can you find omega-6 fatty acids?
They are found in:
1. walnuts
2. sunflower oil
3. sunflower seeds
4. sunflower margarine spread

In the 1980s, two lines of evidence came together on the cardio-protective effect of omega-3 fatty acids. Firstly, epidemiological studies proved beyond any shadow of doubt that populations eating large quantities of fish have very low rates of heart disease. A meta-analysis by He et al found that 5 or more fish meals a week was associated with a 40% reduction in cardiovascular disease. Secondly, long chain omega-3 fatty acids were shown to significantly lower blood fats (triglycerides), reduce inflammation, blood thinning (anti-thrombotic) and relax blood vessels (vasodilatory). All factors are beneficial for lowering cardiovascular risks.

Fish that live in cold water are rich in omega-3 poly unsaturated fatty acids – particularly docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and docosapentaenoic acid (DPA). The NHMRC Nutrient Reference Value for EPA, DPA and DHA is 160mg/day for men and 90mg/day for women. To prevent chronic disease, the values have been set at the 90th percentile. At this level, the targets for omega-3 fatty acids have been revised higher to 610mg/day for men and 430mg/day for women respectively. Where can you find these fatty acids?

From the above table, it is obvious that fish provide the highest quantity of omega-3 fatty acids. A 610mg per day target for men translates into approximately 100g of fish most days of the week! The upper limit for children, adolescents and adults are currently set at 3000mg/day. The GISSI – Prevenzione intervention study found that intake of 850mg of EPA and DHA significantly reduced the risk of sudden cardiac death by 45%. Dietary intake of 850mg of omega-3 fatty acids could be difficult to achieve on a daily basis. One may consider a 1000mg/day fish oil supplement as a preventative measure.

In 2000, De Catherina et al found that both omega-6 fatty acids and omega-3 fatty acids have anti-inflammatory properties; the protective effect appears to increase depending on how unsaturated the molecules (i.e. the number of double bonds). With this new evidence, Nutrient Reference Values have been formally set for these nutrients. The NRV for adequate intake of omega-3 (alpa-linolenic acid) and omega-6 fatty acids (linoleic acid) are 1.3g/day and 13g/day respectively for men and 0.8g/day and 8g/day respectively for women.

Strong scientific evidence linking dietary deficiency of omega-3s with increase risk for cardiovascular events has lead to the creation of the Omega-3 Index (by Clemens von Schacky and Bill Harris). Essentially, the Omega-3 Index represents the percentage of EPA and DHA in red blood cell membranes.
This Index is a measure of the omega-3 status of an individual. As I write, this index is increasingly being used as a valid risk factor for heart disease!

References

1. He K et al. Circulation 2004; 109:2705-11.
2. Sands SA et al. Lipids 2005; 40:343-7.
3. Harris WS. Pharmacol Res 2007; 55:217-223.
4. Sacks FM, Campos H. J Clin Endocrinol Metab 2006; 91:398-400.
5. Asherio A, Am J Med 2002; 113:9S-12S.
6. De Caterina R et al. Am J Clin Nutr 2000; 71:213S-223S.
7. Ferrucci L et al. J Clin Endocrinol Metab 2006; 91:439-446.