Herbal medicines used to manage heart disease

by Monica Wilde, MSc
Research Herbalist

Heart disease, known as cardiovascular disease or CVD, is the leading cause of death in the world. There are many drugs to treat heart disease but many often have side effects, especially when people end up taking 3, 4 or 5 other drugs together (a 'cocktail' of drugs known as polypharmacy). So patients often ask us if there are natural alternatives. Monica looks at the evidence behind some of the herbs that are used by medical herbalists to keep their patients heart healthy.

A significant cause of heart attacks is the thickening of blood with clumping or clotting (platelet activation and aggregation) which can cause blockages in blood flow (hemostasis) and the development of blood clots (thrombosis). So after a heart scare, most patients will be given drugs to keep their blood thin, and flowing smoothly without any platelet clumps or blood clots which could trigger another heart attack. These drugs include low-dose 'baby' aspirin, clopidogrel and in extreme cases, warfarin. 

However, side effects from these drugs are the leading cause of drug side effects. In the United States between 2007 and 2009, there were 50,000 emergency hospital admissions each year caused by drug side effects in patients over 65 years of age. These predominantly involved warfarin (33.3%) and oral antiplatelet drugs (13.3%). In the UK, in 2008/09, more than half a million bed days were attributed to adverse events caused by medicines, costing the NHS £235 million. At least 6.5% of emergency admissions are caused by medicines . 

A study by McEwen (2015) on the use of heart medicines in managing heart disease was published in the journal, Seminars in thrombosis and hemostasis. In the abstract, McEwen reported on several of the herbs that herbalists traditionally use and states that "Herbal medicines have been traditionally used in the management of CVD and can play a role in modifying CVD progression, particularly in platelet function, and have the potential of altering platelet function tests, as well as some coagulation parameters. Herbal medicines, such as feverfew, garlic, ginger, ginseng, motherwort, St John's wort, and willow bark, were found to reduce platelet aggregation. In vitro studies show promise in the reduction of platelet aggregation for green chiretta (Andrographis paniculata), feverfew (Tanacetum parthenium), garlic (Allium sativum), ginger (Zingiber officinalis), ginkgo (Ginkgo biloba), ginseng (Panax ginseng), hawthorn (Crataegus spp.) , horse chestnut (Aesculus hippocastanum), and turmeric (Curcuma longa)."

Another literature review by Rastogi et al., (2015) highlights the cardiovascular benefits of garlic, guggul (Commiphora wightii), hawthorn and arjuna (Terminalia arjuna). These plants have been used in the treatment of heart disease for hundreds of years, and current research methods now support their effective use in the treatment of cardiovascular diseases including ischemic heart disease, congestive heart failure, arrhythmias and hypertension.

 

Herbs used by herbalists

Hawthorn exerts a wide range of effects on the heart including antioxidant activity, increasing the strength of heart muscle contractions, anti-inflammatory effect on the cells, returns the heart to normal size, prevents platelet aggregation, dilates the blood vessels (which decreases blood pressure), protects the lining of blood vessels, protects the heart from injury from the restriction of blood flow to the heart tissues,  it has an antiarrhythmic effect, lipid-lowering effect and decreases arterial blood pressure (Wang, 2013). After a heart attack, changes in the heart such as thinning of the heart wall, changes in the chamber size, cell dimensions, cell numbers, and volume. In herbal medicine, it has been known for a long time that hawthorn both protects the heart, strengthens it and, if a patient goes on to have a heart attack, they recover far better. This was borne out in a in vivo study by Hwang et al., (2008) who found that hawthorn markedly normalised left ventricular chamber volume after heart failure, increased heart wall thickness and strengthened it, and helped the heart to regain its former size and function after heart failure. Extracts include teas and tinctures of the hawthorn leaves, flowers and berries. Hawthorn is not known to interact with anticoagulant drugs (Mills & Bone, 2005). A randomised crossover trial (Tankanow, 2003) showed that standardised hawthorn can be taken alongside digoxin under practitioner supervision. It can be used (again, if monitored) in synergy with antiarrhythmic drugs, beta blockers and high blood pressure drugs.

Motherwort's botanical name of Leonurus cardiaca, a testament to its long history in treating cardiac problems. Recent studies have confirmed its effectiveness, especially its role in treating heart infections (endocarditis) as it is active against Staphylococus aureus. Motherwort contains a natural compound called ursolic acid that is particularly effective in destroying the bacteria's biofilm (Micota et al., 2014).

Feverfew has been well studied as it is also used to prevent platelet clumping which triggers migraines for which it is a well-known preventative. It rarely has side effects when taken in tablet or capsule form - eating the leaves can result in mouth irritation. As long-term use of feverfew leads to a slower clotting of the blood (high prothrombin time reading) it should not be taken with prescription anticoagulant drugs, as the combination of them both taken together, could make your blood too thin.

Garlic is best taken in a capsule. Allicin extracts are particularly effective in helping to keep the blood thin and also in lowering LDL cholesterol in the blood. Like feverfew, when taken on its own there are very few side effects. It works so well, that surgeons will ask you discontinue using garlic supplements prior to any surgery to decrease any risk of bleeding. You should also not take high strength garlic at the same time as anticoagulant drugs without the supervision of a medical practitioner who can ensure that both are taken at the correct dose for the combined approach.

Ginkgo is often used by herbalists to improve circulation in the small vessels in the brain and extremities. So often used in patients with early signs of dementia such as memory loss, and in cases or peripheral arterial occlusive disease. Standardised ginkgo rarely causes side effects, however high doses - common in an unregulated supplements indusry - can cause adverse reactions. Trials show that on its own it does not effect platelets so its effect is mainly as a blood thinner. Ginkgo should be ceased 3 days before planned surgery to lower any risk of bleeding. If you are already taking anticoagulant/antiplatelet medication it should be used with caution. However, a trial with patients taking standardised ginkgo alongside warfarin, showed that the INR rate did not change during the course of the trial. This shows how important it is to talk to your doctor about what you are taking. This knowledge can help them to develop a prescribing plan that gives you stability and respects your choice to also take supplements. 

Green chiretta (Andrographis) is usually used short-term by herbalists to treat viral and bacterial infections, ranging from colds to dysentery.It is fairly well tolerated except at very high strengths. It does have its own proven antiplatelet and anticoagulant actions but is found unlikely to interact with conventional blood thinning drugs.

Willow is one of the original sources of salicylic acid which is made, pharmaceutically, as aspirin. Although clinical trials have shown it to have an anticoagulant action, herbalists tend to avoid using it as a long-term treatment due to its high tannin content. Also in practice it has been found that willow only slightly potentiates the action of anticoagulant drugs.

 

Herb-drug interactions

Drugs can interact with other drugs, herbs, food and drink. So great care should be taken in the 'cocktail' that you may end up taking. Although each drug is carefully tested, few are tested alongside other manufacturers' drugs in robust clinical trials. So knowledge of interactions is either theoretical (i.e. its likely to happen because of the action or pharmacology of two substances) or from post-marketing surveillance (what is reported after a drug has been placed on the market). The latter is monitored by the Yellow Card reporting system but not all drug interactions are reported.

That herbs and drugs can sometimes interact is well-known. McEwen reports that cranberry, red sage root (danshen), Chinese angelica (dong quai), ginkgo, ginseng, green tea, and St John's wort were found to have potential interactions with warfarin. It is also known that St John's wort interacts with clopidogrel and danshen with aspirin. The study advised that repeat testing of platelet function and coagulation studies, particularly for patients on warfarin therapy, may be required, after exclusion of herbal medicines that could have possibly affected initial test results. (Warfarin has many interactions. Not just with herbs, but with many other drugs and also food like grapefruit, cranberry and black pepper.)

However, in managing heart health, herb-drug interactions can be beneficial, provided that they are professionally managed. Hawthorn for example, can provide supportive interaction as, because it augments the action of the drug, its use results in lower drug doses for a patient, thereby reducing the drug's unwanted side effects (Stargrove et al, 2008). It is generally best, when managing long-term conditions, to correct the diet and supplement with herbs first - to reach the optimum level of health that a patient can attain and maintain - before tests are done, as then the amount of a drug prescribed will be the actual dose truly required by the patient.

Unfortunately, heart attacks often come out of the blue, and on leaving hospital a patient has lots of pills to take and the fear that if they don't take them that their life is in danger. So introducing herbs at this stage, does require a knowledgeable herbal practitioner and ideally the co-operation of your doctor. Herbalists are happy to communicate with your doctor about your plans. Sadly not all doctors are open-minded but you need to remember that it's your body, and your choice of treatment. Herbal medicine is biochemistry, based on science, and a good doctor will be happy for your treatment to "do no harm" and if drug side effects have affected your quality of life they should not object to you seeking to improve that under the guidance of a qualified medical herbalist. 

 

Food-drug interactions

Olive oil. Yes, even olive oil can interact with some drugs. If you are also taking drugs for high blood pressure be aware that taking of 3-4 spoonsful of extra virgin olive oil daily for 6 months compared to safflower oil in a crossover study led to significant reductions in the use of high blood pressure medications including atenolol, nifedipine, lisinopril, doxazosin, and hydrochlorothiazide. So if you change your cooking oil from sunflower to olive oil in part of your efforts to improve your diet, be aware of this.

Grapefruit. Grapefruit is known to interact with warfarin and drinking grapefruit juice should be avoided.

Black pepper. Piperine is a natural phytochemical found in black pepper which makes other chemicals (natural or otherwise) more bioavailable. The result of this is that it can increase the effect of any drug or herb that you are taking.

Seaweed. Anticoagulant effects are produced by some seaweed polysaccharides. Red algae, e.g. lambda-carrageenan containing sulphated polysaccharides that have 10% of the potency of heparin, inhibit thrombin both directly and indirectly. Brown algae (kelp, kombu, nori) contain polysaccharides called fucoidans) also inhibit blood clotting although not much is yet known about how effectively these work from food.
 

Taking it further

If you are considering using a herb to manage heart disease, please make an appointment to see a medical herbalist who can advise on the right course of treatment in conjunction with any drugs that you have been prescribed by your doctor. 

 

References

Hwang HS, Bleske BE, Ghannam MM, Converso K, Russell MW, Hunter JC, Boluyt MO. (2008). Effects of hawthorn on cardiac remodeling and left ventricular dysfunction after 1 month of pressure overload-induced cardiac hypertrophy in rats. Cardiovasc Drugs Ther, 22(1), 19-28. doi: 10.1007/s10557-008-6082-2

McEwen BJ. (2015) The influence of herbal medicine on platelet function and coagulation: a narrative review. Semin Thromb Hemost, 41(3), 300-14. doi: 10.1055/s-0035-1549089

Micota B, Sadowska B, Podsędek A, Redzynia M, Różalska B. (2014). Leonurus cardiaca L. herb--a derived extract and an ursolic acid as the factors affecting the adhesion capacity of Staphylococcus aureus in the context of infective endocarditis. Acta Biochim Pol, 61(2), 385-388. PubMed PMID: 24918490.

Rastogi S, Pandey MM, Rawat AK. (2015). Traditional herbs: a remedy for cardiovascular disorders. Phytomedicine, 10, S0944-7113(15)00331-1. doi: 10.1016/j.phymed.2015.10.012.

Stargrove, MB, Treasure, J and McKee, DL (2008). Herb, Nutrient, and Drug Interactions: Clinical implications and therapeutic strategies. Mosby Elsevier, Missouri; USA.

Wang J, Xiong X, Feng B. (2013). Effect of crataegus usage in cardiovascular disease prevention: an evidence-based approach. Evid Based Complement Alternat Med, 2013, 149363. doi: 10.1155/2013/149363